[RFC,10/13] gfxstream + rutabaga: add initial support for gfxstream

Commit Message

Gurchetan Singh April 21, 2023, 1:12 a.m. UTC

This adds initial support for gfxstream and cross-domain.  Both
features rely on virtio-gpu blob resources and context types, which
are also implemented in this patch.

gfxstream has a long and illustrious history in Android graphics
paravirtualization.  It has been powering graphics in the Android
Studio Emulator for more than a decade, which is the main developer
platform.

Originally conceived by Jesse Hall, it was first known as "EmuGL" [a].
The key design characteristic was a 1:1 threading model and
auto-generation, which fit nicely with the OpenGLES spec.  It also
allowed easy layering with ANGLE on the host, which provides the GLES
implementations on Windows or MacOS enviroments.

gfxstream has traditionally been maintained by a single engineer, and
between 2015 to 2021, the iron throne passed to Frank Yang.  Just to
name a few accomplishments in a reign filled with many of them: newer
versions of GLES, address space graphics, snapshot support and CTS
compliant Vulkan [b].

One major drawback was the use of out-of-tree goldfish drivers.
Android engineers didn't know much about DRM/KMS and especially TTM so
a simple guest to host pipe was conceived.

Luckily, virtio-gpu 3D started to emerge in 2016 due to the work of
the Mesa/virglrenderer communities.  In 2018, the initial virtio-gpu
port of gfxstream was done by Cuttlefish enthusiast Alistair Delva.
It was a symbol compatible replacement of virglrenderer [c] and named
"AVDVirglrenderer".  This implementation forms the basis of the
current gfxstream host implementation still in use today.

cross-domain support follows a similar arc.  Originally conceived by
Wayland aficionado David Reveman and crosvm enjoyer Zach Reizner in
2018, it initially relied on the downstream "virtio-wl" device.

In 2020 and 2021, virtio-gpu was extended to include blob resources
and multiple timelines by yours truly, features gfxstream/cross-domain
both require to function correctly.

Right now, we stand at the precipice of a truly fantastic possibility:
the Android Emulator powered by upstream QEMU and upstream Linux
kernel.  gfxstream will then be packaged properfully, and app
developers can even fix gfxstream bugs on their own if they encounter
them.

It's been quite the ride, my friends.  Where will gfxstream head next,
nobody really knows.  I wouldn't be surprised if it's around for
another decade, maintained by a new generation of Android graphics
enthusiasts.  One thing is for sure, though -- it'll be filled with
friendship and magic!

Technical details:
  - Very simple initial display integration: just used Pixman
  - Largely, 1:1 mapping of virtio-gpu hypercalls to rutabaga function
    calls

[a] https://android-review.googlesource.com/c/platform/development/+/34470
[b] https://android-review.googlesource.com/q/topic:%22vulkan-hostconnection-start%22
[c] https://android-review.googlesource.com/c/device/generic/goldfish-opengl/+/761927

Signed-off-by: Gurchetan Singh <[e-mail]>
---
 hw/display/virtio-gpu-rutabaga.c | 995 +++++++++++++++++++++++++++++++
 1 file changed, 995 insertions(+)
 create mode 100644 hw/display/virtio-gpu-rutabaga.c

Comments

Akihiko Odaki April 22, 2023, 3:37 p.m. UTC | #1

On 2023/04/21 10:12, Gurchetan Singh wrote:
> This adds initial support for gfxstream and cross-domain.  Both
> features rely on virtio-gpu blob resources and context types, which
> are also implemented in this patch.
> 
> gfxstream has a long and illustrious history in Android graphics
> paravirtualization.  It has been powering graphics in the Android
> Studio Emulator for more than a decade, which is the main developer
> platform.
> 
> Originally conceived by Jesse Hall, it was first known as "EmuGL" [a].
> The key design characteristic was a 1:1 threading model and
> auto-generation, which fit nicely with the OpenGLES spec.  It also
> allowed easy layering with ANGLE on the host, which provides the GLES
> implementations on Windows or MacOS enviroments.
> 
> gfxstream has traditionally been maintained by a single engineer, and
> between 2015 to 2021, the iron throne passed to Frank Yang.  Just to
> name a few accomplishments in a reign filled with many of them: newer
> versions of GLES, address space graphics, snapshot support and CTS
> compliant Vulkan [b].
> 
> One major drawback was the use of out-of-tree goldfish drivers.
> Android engineers didn't know much about DRM/KMS and especially TTM so
> a simple guest to host pipe was conceived.
> 
> Luckily, virtio-gpu 3D started to emerge in 2016 due to the work of
> the Mesa/virglrenderer communities.  In 2018, the initial virtio-gpu
> port of gfxstream was done by Cuttlefish enthusiast Alistair Delva.
> It was a symbol compatible replacement of virglrenderer [c] and named
> "AVDVirglrenderer".  This implementation forms the basis of the
> current gfxstream host implementation still in use today.
> 
> cross-domain support follows a similar arc.  Originally conceived by
> Wayland aficionado David Reveman and crosvm enjoyer Zach Reizner in
> 2018, it initially relied on the downstream "virtio-wl" device.
> 
> In 2020 and 2021, virtio-gpu was extended to include blob resources
> and multiple timelines by yours truly, features gfxstream/cross-domain
> both require to function correctly.
> 
> Right now, we stand at the precipice of a truly fantastic possibility:
> the Android Emulator powered by upstream QEMU and upstream Linux
> kernel.  gfxstream will then be packaged properfully, and app
> developers can even fix gfxstream bugs on their own if they encounter
> them.
> 
> It's been quite the ride, my friends.  Where will gfxstream head next,
> nobody really knows.  I wouldn't be surprised if it's around for
> another decade, maintained by a new generation of Android graphics
> enthusiasts.  One thing is for sure, though -- it'll be filled with
> friendship and magic!
> 
> Technical details:
>    - Very simple initial display integration: just used Pixman
>    - Largely, 1:1 mapping of virtio-gpu hypercalls to rutabaga function
>      calls
> 
> [a] https://android-review.googlesource.com/c/platform/development/+/34470
> [b] https://android-review.googlesource.com/q/topic:%22vulkan-hostconnection-start%22
> [c] https://android-review.googlesource.com/c/device/generic/goldfish-opengl/+/761927
> 
> Signed-off-by: Gurchetan Singh <[e-mail]>
> ---
>   hw/display/virtio-gpu-rutabaga.c | 995 +++++++++++++++++++++++++++++++
>   1 file changed, 995 insertions(+)
>   create mode 100644 hw/display/virtio-gpu-rutabaga.c
> 
> diff --git a/hw/display/virtio-gpu-rutabaga.c b/hw/display/virtio-gpu-rutabaga.c
> new file mode 100644
> index 0000000000..5fd1154198
> --- /dev/null
> +++ b/hw/display/virtio-gpu-rutabaga.c
> @@ -0,0 +1,995 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include "qemu/osdep.h"
> +#include "qemu/error-report.h"
> +#include "qemu/iov.h"
> +#include "trace.h"
> +#include "hw/virtio/virtio.h"
> +#include "hw/virtio/virtio-gpu.h"
> +#include "hw/virtio/virtio-gpu-pixman.h"
> +#include "hw/virtio/virtio-iommu.h"
> +
> +#include <rutabaga_gfx/rutabaga_gfx_ffi.h>
> +
> +static int virtio_gpu_rutabaga_init(VirtIOGPU *g);
> +
> +#define GET_VIRTIO_GPU_GL(x)                                                  \
> +        VirtIOGPUGL *virtio_gpu = VIRTIO_GPU_GL(x);                           \

It's confusing to name a VirtIOGPUGL pointer derived from a VirtIOGPU 
pointer "virtio_gpu". "gl", the name used in virtio-gpu-gl.c is less 
confusing though it's a bit strange considering the VirtIOGPU pointer is 
named "g".

I also doubt this macro (and following GET_RUTABAGA()) makes sense. It's 
confusing that they declare a variable, and it's not really saving code 
either as the content of each macro is just one line. But other people 
may prefer these macros to stay.

> +
> +#define GET_RUTABAGA(x)                                                       \
> +        struct rutabaga *rutabaga = (struct rutabaga *)(x->rutabaga);         \

Wrap x with parentheses. Also you don't need casting from (void *) since 
it's C.

> +
> +#define CHECK(condition, cmd)                                                 \
> +    do {                                                                      \
> +        if (!condition) {                                                     \
> +            qemu_log_mask(LOG_GUEST_ERROR, "CHECK_RESULT failed in %s() %s:"  \

This macro is named CHECK but it says CHECK_RESULT.

> +                          "%d\n", __func__, __FILE__, __LINE__);              \
> +            cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;                          \
> +            return;                                                           \
> +       }                                                                      \
> +    } while (0)
> +
> +#define CHECK_RESULT(result, cmd) CHECK(result == 0, cmd)
> +
> +static void
> +virtio_gpu_rutabaga_update_cursor(VirtIOGPU *g, struct virtio_gpu_scanout *s,
> +                                  uint32_t resource_id)
> +{
> +    struct virtio_gpu_simple_resource *res;
> +    struct rutabaga_transfer transfer = { 0 };
> +    struct iovec transfer_iovec;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    res = virtio_gpu_find_resource(g, resource_id);
> +    if (!res) {
> +        return;
> +    }
> +
> +    if (res->width != s->current_cursor->width ||
> +        res->height != s->current_cursor->height) {
> +        return;
> +    }
> +
> +    transfer.x = 0;
> +    transfer.y = 0;
> +    transfer.z = 0;
> +    transfer.w = res->width;
> +    transfer.h = res->height;
> +    transfer.d = 1;
> +
> +    transfer_iovec.iov_base = (void *)s->current_cursor->data;
> +    transfer_iovec.iov_len = res->width * res->height * 4;
> +
> +    rutabaga_resource_transfer_read(rutabaga, 0,
> +                                    resource_id, &transfer,
> +                                    &transfer_iovec);
> +}
> +
> +static void
> +virtio_gpu_rutabaga_gl_flushed(VirtIOGPUBase *b)
> +{
> +    VirtIOGPU *g = VIRTIO_GPU(b);
> +    virtio_gpu_process_cmdq(g);
> +}
> +
> +static void
> +rutabaga_cmd_create_resource_2d(VirtIOGPU *g,
> +                                struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct rutabaga_create_3d rc_3d = { 0 };
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_create_2d c2d;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(c2d);
> +    trace_virtio_gpu_cmd_res_create_2d(c2d.resource_id, c2d.format,
> +                                       c2d.width, c2d.height);
> +
> +    rc_3d.target = 2;
> +    rc_3d.format = c2d.format;
> +    rc_3d.bind = (1 << 1);
> +    rc_3d.width = c2d.width;
> +    rc_3d.height = c2d.height;
> +    rc_3d.depth = 1;
> +    rc_3d.array_size = 1;
> +    rc_3d.last_level = 0;
> +    rc_3d.nr_samples = 0;
> +    rc_3d.flags = VIRTIO_GPU_RESOURCE_FLAG_Y_0_TOP;
> +
> +    result = rutabaga_resource_create_3d(rutabaga, c2d.resource_id, &rc_3d);
> +    CHECK_RESULT(result, cmd);
> +
> +    res = g_new0(struct virtio_gpu_simple_resource, 1);
> +    res->width = c2d.width;
> +    res->height = c2d.height;
> +    res->format = c2d.format;
> +    res->resource_id = c2d.resource_id;
> +
> +    QTAILQ_INSERT_HEAD(&g->reslist, res, next);
> +}
> +
> +static void
> +rutabaga_cmd_create_resource_3d(VirtIOGPU *g,
> +                                struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct rutabaga_create_3d rc_3d = { 0 };
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_create_3d c3d;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(c3d);
> +
> +    trace_virtio_gpu_cmd_res_create_3d(c3d.resource_id, c3d.format,
> +                                       c3d.width, c3d.height, c3d.depth);
> +
> +    rc_3d.target = c3d.target;
> +    rc_3d.format = c3d.format;
> +    rc_3d.bind = c3d.bind;
> +    rc_3d.width = c3d.width;
> +    rc_3d.height = c3d.height;
> +    rc_3d.depth = c3d.depth;
> +    rc_3d.array_size = c3d.array_size;
> +    rc_3d.last_level = c3d.last_level;
> +    rc_3d.nr_samples = c3d.nr_samples;
> +    rc_3d.flags = c3d.flags;
> +
> +    result = rutabaga_resource_create_3d(rutabaga, c3d.resource_id, &rc_3d);
> +    CHECK_RESULT(result, cmd);
> +
> +    res = g_new0(struct virtio_gpu_simple_resource, 1);
> +    res->width = c3d.width;
> +    res->height = c3d.height;
> +    res->format = c3d.format;
> +    res->resource_id = c3d.resource_id;
> +
> +    QTAILQ_INSERT_HEAD(&g->reslist, res, next);
> +}
> +
> +static int32_t rutabaga_handle_unmap(VirtIOGPU *g,
> +                                     struct virtio_gpu_simple_resource *res)
> +{
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    res->mapped = NULL;
> +    return rutabaga_resource_unmap(rutabaga, res->resource_id);
> +}
> +
> +static void
> +rutabaga_cmd_resource_unref(VirtIOGPU *g,
> +                            struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_unref unref;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(unref);
> +
> +    trace_virtio_gpu_cmd_res_unref(unref.resource_id);
> +
> +    res = virtio_gpu_find_resource(g, unref.resource_id);
> +    CHECK(res, cmd);
> +
> +    result = rutabaga_resource_unref(rutabaga, unref.resource_id);
> +    CHECK_RESULT(result, cmd);
> +
> +    if (res->image) {
> +        pixman_image_unref(res->image);
> +    }
> +
> +    if (res->mapped) {
> +        result = rutabaga_handle_unmap(g, res);
> +        CHECK(result, cmd);

If this check fails, res, which has a dangling pointer in "image" 
member, will be kept in reslist.

> +    }
> +
> +    QTAILQ_REMOVE(&g->reslist, res, next);
> +    g_free(res);
> +}
> +
> +static void
> +rutabaga_cmd_context_create(VirtIOGPU *g,
> +                            struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_ctx_create cc;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(cc);
> +    trace_virtio_gpu_cmd_ctx_create(cc.hdr.ctx_id,
> +                                    cc.debug_name);
> +
> +    result = rutabaga_context_create(rutabaga, cc.hdr.ctx_id, cc.context_init,
> +                                     cc.debug_name, cc.nlen);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_context_destroy(VirtIOGPU *g,
> +                             struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_ctx_destroy cd;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(cd);
> +    trace_virtio_gpu_cmd_ctx_destroy(cd.hdr.ctx_id);
> +
> +    result = rutabaga_context_destroy(rutabaga, cd.hdr.ctx_id);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_resource_flush(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result, i;
> +    struct virtio_gpu_scanout *scanout = NULL;
> +    struct virtio_gpu_simple_resource *res;
> +    struct rutabaga_transfer transfer = { 0 };
> +    struct iovec transfer_iovec;
> +    struct virtio_gpu_resource_flush rf;
> +    bool found = false;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(rf);
> +    trace_virtio_gpu_cmd_res_flush(rf.resource_id,
> +                                   rf.r.width, rf.r.height, rf.r.x, rf.r.y);
> +
> +    res = virtio_gpu_find_resource(g, rf.resource_id);
> +    CHECK(res, cmd);
> +
> +    for (i = 0; i < g->parent_obj.conf.max_outputs; i++) {
> +        scanout = &g->parent_obj.scanout[i];
> +        if (i == res->scanout_bitmask) {

This compares an index with bitmask; I doubt that's what you want to do.

> +            found = true;
> +            break;
> +        }
> +    }
> +
> +    if (!found) {
> +        return;
> +    }
> +
> +    transfer.x = 0;
> +    transfer.y = 0;
> +    transfer.z = 0;
> +    transfer.w = res->width;
> +    transfer.h = res->height;
> +    transfer.d = 1;
> +
> +    transfer_iovec.iov_base = (void *)pixman_image_get_data(res->image);
> +    transfer_iovec.iov_len = res->width * res->height * 4;
> +
> +    result = rutabaga_resource_transfer_read(rutabaga, 0,
> +                                             rf.resource_id, &transfer,
> +                                             &transfer_iovec);
> +    CHECK_RESULT(result, cmd);
> +    dpy_gfx_update_full(scanout->con);
> +}
> +
> +static void
> +rutabaga_cmd_set_scanout(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
> +{
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_scanout *scanout = NULL;
> +    struct virtio_gpu_set_scanout ss;
> +
> +    VIRTIO_GPU_FILL_CMD(ss);
> +    trace_virtio_gpu_cmd_set_scanout(ss.scanout_id, ss.resource_id,
> +                                     ss.r.width, ss.r.height, ss.r.x, ss.r.y);
> +
> +    scanout = &g->parent_obj.scanout[ss.scanout_id];
> +    g->parent_obj.enable = 1;
> +
> +    res = virtio_gpu_find_resource(g, ss.resource_id);
> +    CHECK(res, cmd);
> +
> +    if (!res->image) {
> +        pixman_format_code_t pformat;
> +        pformat = virtio_gpu_get_pixman_format(res->format);
> +        CHECK(pformat, cmd);
> +
> +        res->image = pixman_image_create_bits(pformat,
> +                                              res->width,
> +                                              res->height,
> +                                              NULL, 0);
> +        CHECK(res->image, cmd);
> +        pixman_image_ref(res->image);
> +    }
> +
> +    /* realloc the surface ptr */
> +    scanout->ds = qemu_create_displaysurface_pixman(res->image);
> +    dpy_gfx_replace_surface(scanout->con, NULL);

Do you really need to assign NULL first? Maybe it was necessary in an 
old version of QEMU, but I don't think it's still necessary.

> +    dpy_gfx_replace_surface(scanout->con, scanout->ds);
> +    res->scanout_bitmask = ss.scanout_id;
> +}
> +
> +static void
> +rutabaga_cmd_submit_3d(VirtIOGPU *g,
> +                       struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_cmd_submit cs;
> +    void *buf;
> +    size_t s;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(cs);
> +    trace_virtio_gpu_cmd_ctx_submit(cs.hdr.ctx_id, cs.size);
> +
> +    buf = g_malloc(cs.size);
> +    s = iov_to_buf(cmd->elem.out_sg, cmd->elem.out_num,
> +                   sizeof(cs), buf, cs.size);
> +    if (s != cs.size) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: size mismatch (%zd/%d)",
> +                      __func__, s, cs.size);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
> +        goto out;
> +    }
> +
> +    result = rutabaga_submit_command(rutabaga, cs.hdr.ctx_id, buf, cs.size);
> +    CHECK_RESULT(result, cmd);

This check leaks buf if it fails. You may use g_autofree; see 
docs/devel/style.rst for more information on g_autofree.

> +
> +out:
> +    g_free(buf);
> +}
> +
> +static void
> +rutabaga_cmd_transfer_to_host_2d(VirtIOGPU *g,
> +                                 struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct rutabaga_transfer transfer = { 0 };
> +    struct virtio_gpu_transfer_to_host_2d t2d;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(t2d);
> +    trace_virtio_gpu_cmd_res_xfer_toh_2d(t2d.resource_id);
> +
> +    transfer.x = t2d.r.x;
> +    transfer.y = t2d.r.y;
> +    transfer.z = 0;
> +    transfer.w = t2d.r.width;
> +    transfer.h = t2d.r.height;
> +    transfer.d = 1;
> +
> +    result = rutabaga_resource_transfer_write(rutabaga, 0, t2d.resource_id,
> +                                              &transfer);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_transfer_to_host_3d(VirtIOGPU *g,
> +                                 struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct rutabaga_transfer transfer = { 0 };
> +    struct virtio_gpu_transfer_host_3d t3d;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(t3d);
> +    trace_virtio_gpu_cmd_res_xfer_toh_3d(t3d.resource_id);
> +
> +    transfer.x = t3d.box.x;
> +    transfer.y = t3d.box.y;
> +    transfer.z = t3d.box.z;
> +    transfer.w = t3d.box.w;
> +    transfer.h = t3d.box.h;
> +    transfer.d = t3d.box.d;
> +    transfer.level = t3d.level;
> +    transfer.stride = t3d.stride;
> +    transfer.layer_stride = t3d.layer_stride;
> +    transfer.offset = t3d.offset;
> +
> +    result = rutabaga_resource_transfer_write(rutabaga, t3d.hdr.ctx_id,
> +                                              t3d.resource_id, &transfer);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_transfer_from_host_3d(VirtIOGPU *g,
> +                                   struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct rutabaga_transfer transfer = { 0 };
> +    struct virtio_gpu_transfer_host_3d t3d;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(t3d);
> +    trace_virtio_gpu_cmd_res_xfer_fromh_3d(t3d.resource_id);
> +
> +    transfer.x = t3d.box.x;
> +    transfer.y = t3d.box.y;
> +    transfer.z = t3d.box.z;
> +    transfer.w = t3d.box.w;
> +    transfer.h = t3d.box.h;
> +    transfer.d = t3d.box.d;
> +    transfer.level = t3d.level;
> +    transfer.stride = t3d.stride;
> +    transfer.layer_stride = t3d.layer_stride;
> +    transfer.offset = t3d.offset;
> +
> +    result = rutabaga_resource_transfer_read(rutabaga, t3d.hdr.ctx_id,
> +                                             t3d.resource_id, &transfer, NULL);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_attach_backing(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
> +{
> +    struct rutabaga_iovecs vecs = { 0 };
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_attach_backing att_rb;
> +    struct iovec *res_iovs;
> +    uint32_t res_niov;
> +    int ret;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(att_rb);
> +    trace_virtio_gpu_cmd_res_back_attach(att_rb.resource_id);
> +
> +    res = virtio_gpu_find_resource(g, att_rb.resource_id);
> +    if (!res) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",
> +                      __func__, att_rb.resource_id);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
> +        return;
> +    }
> +
> +    if (res->iov) {
> +        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
> +        return;
> +    }
> +
> +    ret = virtio_gpu_create_mapping_iov(g, att_rb.nr_entries, sizeof(att_rb),
> +                                        cmd, NULL, &res_iovs, &res_niov);
> +    if (ret != 0) {
> +        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
> +        return;
> +    }
> +
> +    vecs.iovecs = res_iovs;
> +    vecs.num_iovecs = res_niov;
> +
> +    ret = rutabaga_resource_attach_backing(rutabaga, att_rb.resource_id, &vecs);
> +    if (ret != 0) {
> +        virtio_gpu_cleanup_mapping_iov(g, res_iovs, res_niov);
> +    }
> +}
> +
> +static void
> +rutabaga_cmd_detach_backing(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
> +{
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_detach_backing detach_rb;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(detach_rb);
> +    trace_virtio_gpu_cmd_res_back_detach(detach_rb.resource_id);
> +
> +    res = virtio_gpu_find_resource(g, detach_rb.resource_id);
> +    CHECK(res, cmd);
> +
> +    rutabaga_resource_detach_backing(rutabaga,
> +                                     detach_rb.resource_id);
> +
> +    virtio_gpu_cleanup_mapping(g, res);
> +}
> +
> +static void
> +rutabaga_cmd_ctx_attach_resource(VirtIOGPU *g,
> +                                 struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_ctx_resource att_res;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(att_res);
> +    trace_virtio_gpu_cmd_ctx_res_attach(att_res.hdr.ctx_id,
> +                                        att_res.resource_id);
> +
> +    result = rutabaga_context_attach_resource(rutabaga, att_res.hdr.ctx_id,
> +                                              att_res.resource_id);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_ctx_detach_resource(VirtIOGPU *g,
> +                                 struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_ctx_resource det_res;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(det_res);
> +    trace_virtio_gpu_cmd_ctx_res_detach(det_res.hdr.ctx_id,
> +                                        det_res.resource_id);
> +
> +    result = rutabaga_context_detach_resource(rutabaga, det_res.hdr.ctx_id,
> +                                              det_res.resource_id);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_get_capset_info(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_get_capset_info info;
> +    struct virtio_gpu_resp_capset_info resp;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(info);
> +
> +    result = rutabaga_get_capset_info(rutabaga, info.capset_index,
> +                                      &resp.capset_id, &resp.capset_max_version,
> +                                      &resp.capset_max_size);
> +    CHECK_RESULT(result, cmd);
> +
> +    resp.hdr.type = VIRTIO_GPU_RESP_OK_CAPSET_INFO;
> +    virtio_gpu_ctrl_response(g, cmd, &resp.hdr, sizeof(resp));
> +}
> +
> +static void
> +rutabaga_cmd_get_capset(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_get_capset gc;
> +    struct virtio_gpu_resp_capset *resp;
> +    uint32_t capset_size;
> +    uint32_t current_id;
> +    bool found = false;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(gc);
> +    for (uint32_t i = 0; i < virtio_gpu->num_capsets; i++) {
> +        result = rutabaga_get_capset_info(rutabaga, i,
> +                                          &current_id, &capset_size,
> +                                          &capset_size);
> +        CHECK_RESULT(result, cmd);
> +
> +        if (current_id == gc.capset_id) {
> +            found = true;
> +            break;
> +        }
> +    }
> +
> +    if (!found) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "capset not found!");
> +        return;
> +    }
> +
> +    resp = g_malloc0(sizeof(*resp) + capset_size);
> +    resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET;
> +    rutabaga_get_capset(rutabaga, gc.capset_id, gc.capset_version,
> +                       (uint8_t *)resp->capset_data, capset_size);
> +
> +    virtio_gpu_ctrl_response(g, cmd, &resp->hdr, sizeof(*resp) + capset_size);
> +    g_free(resp);
> +}
> +
> +static void
> +rutabaga_cmd_resource_create_blob(VirtIOGPU *g,
> +                                  struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int result;
> +    struct rutabaga_iovecs vecs = { 0 };
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_create_blob cblob;
> +    struct rutabaga_create_blob rc_blob = { 0 };
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(cblob);
> +    trace_virtio_gpu_cmd_res_create_blob(cblob.resource_id, cblob.size);
> +
> +    CHECK(cblob.resource_id != 0, cmd);
> +
> +    res = g_new0(struct virtio_gpu_simple_resource, 1);
> +    QTAILQ_INSERT_HEAD(&g->reslist, res, next);

This inserts res to reslit before if the creation actually succeeds, 
which doesn't seem right.

> +
> +    res->resource_id = cblob.resource_id;
> +    res->blob_size = cblob.size;
> +
> +    if (cblob.blob_mem != VIRTIO_GPU_BLOB_MEM_HOST3D) {
> +        result = virtio_gpu_create_mapping_iov(g, cblob.nr_entries,
> +                                               sizeof(cblob), cmd, &res->addrs,
> +                                               &res->iov, &res->iov_cnt);
> +        CHECK_RESULT(result, cmd);
> +    }
> +
> +    rc_blob.blob_id = cblob.blob_id;
> +    rc_blob.blob_mem = cblob.blob_mem;
> +    rc_blob.blob_flags = cblob.blob_flags;
> +    rc_blob.size = cblob.size;
> +
> +    vecs.iovecs = res->iov;
> +    vecs.num_iovecs = res->iov_cnt;
> +
> +    result = rutabaga_resource_create_blob(rutabaga, cblob.hdr.ctx_id,
> +                                           cblob.resource_id, &rc_blob, &vecs,
> +                                           NULL);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +rutabaga_cmd_resource_map_blob(VirtIOGPU *g,
> +                               struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_simple_resource *res;
> +    struct rutabaga_mapping mapping = { 0 };
> +    struct virtio_gpu_resource_map_blob mblob;
> +    struct virtio_gpu_resp_map_info resp;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(mblob);
> +
> +    CHECK(mblob.resource_id != 0, cmd);
> +
> +    res = virtio_gpu_find_resource(g, mblob.resource_id);
> +    CHECK(res, cmd);
> +
> +    result = rutabaga_resource_map(rutabaga, mblob.resource_id, &mapping);
> +    CHECK_RESULT(result, cmd);
> +
> +    memset(&resp, 0, sizeof(resp));
> +    resp.hdr.type = VIRTIO_GPU_RESP_OK_MAP_INFO;
> +    result = rutabaga_resource_map_info(rutabaga, mblob.resource_id,
> +                                        &resp.map_info);
> +
> +    CHECK_RESULT(result, cmd);
> +    virtio_gpu_ctrl_response(g, cmd, &resp.hdr, sizeof(resp));
> +}
> +
> +static void
> +rutabaga_cmd_resource_unmap_blob(VirtIOGPU *g,
> +                                 struct virtio_gpu_ctrl_command *cmd)
> +{
> +    int32_t result;
> +    struct virtio_gpu_simple_resource *res;
> +    struct virtio_gpu_resource_unmap_blob ublob;
> +
> +    VIRTIO_GPU_FILL_CMD(ublob);
> +
> +    CHECK(ublob.resource_id != 0, cmd);
> +
> +    res = virtio_gpu_find_resource(g, ublob.resource_id);
> +    CHECK(res, cmd);
> +
> +    result = rutabaga_handle_unmap(g, res);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +virtio_gpu_rutabaga_process_cmd(VirtIOGPU *g,
> +                                struct virtio_gpu_ctrl_command *cmd)
> +{
> +    struct rutabaga_fence fence = { 0 };
> +    int32_t result;
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    VIRTIO_GPU_FILL_CMD(cmd->cmd_hdr);
> +
> +    switch (cmd->cmd_hdr.type) {
> +    case VIRTIO_GPU_CMD_CTX_CREATE:
> +        rutabaga_cmd_context_create(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_CTX_DESTROY:
> +        rutabaga_cmd_context_destroy(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_CREATE_2D:
> +        rutabaga_cmd_create_resource_2d(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_CREATE_3D:
> +        rutabaga_cmd_create_resource_3d(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_SUBMIT_3D:
> +        rutabaga_cmd_submit_3d(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D:
> +        rutabaga_cmd_transfer_to_host_2d(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_TRANSFER_TO_HOST_3D:
> +        rutabaga_cmd_transfer_to_host_3d(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_TRANSFER_FROM_HOST_3D:
> +        rutabaga_cmd_transfer_from_host_3d(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING:
> +        rutabaga_cmd_attach_backing(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING:
> +        rutabaga_cmd_detach_backing(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_SET_SCANOUT:
> +        rutabaga_cmd_set_scanout(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_FLUSH:
> +        rutabaga_cmd_resource_flush(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_UNREF:
> +        rutabaga_cmd_resource_unref(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_CTX_ATTACH_RESOURCE:
> +        rutabaga_cmd_ctx_attach_resource(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_CTX_DETACH_RESOURCE:
> +        rutabaga_cmd_ctx_detach_resource(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_GET_CAPSET_INFO:
> +        rutabaga_cmd_get_capset_info(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_GET_CAPSET:
> +        rutabaga_cmd_get_capset(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_GET_DISPLAY_INFO:
> +        virtio_gpu_get_display_info(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_GET_EDID:
> +        virtio_gpu_get_edid(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB:
> +        rutabaga_cmd_resource_create_blob(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_MAP_BLOB:
> +        rutabaga_cmd_resource_map_blob(g, cmd);
> +        break;
> +    case VIRTIO_GPU_CMD_RESOURCE_UNMAP_BLOB:
> +        rutabaga_cmd_resource_unmap_blob(g, cmd);
> +        break;
> +    default:
> +        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
> +        break;
> +    }
> +
> +    if (cmd->finished) {
> +        return;
> +    }
> +    if (cmd->error) {
> +        fprintf(stderr, "%s: ctrl 0x%x, error 0x%x\n", __func__,
> +                cmd->cmd_hdr.type, cmd->error);

Use: error_report()
This one is also briefly described in style.rst

> +        virtio_gpu_ctrl_response_nodata(g, cmd, cmd->error);
> +        return;
> +    }
> +    if (!(cmd->cmd_hdr.flags & VIRTIO_GPU_FLAG_FENCE)) {
> +        virtio_gpu_ctrl_response_nodata(g, cmd, VIRTIO_GPU_RESP_OK_NODATA);
> +        return;
> +    }
> +
> +    fence.flags = cmd->cmd_hdr.flags;
> +    fence.ctx_id = cmd->cmd_hdr.ctx_id;
> +    fence.fence_id = cmd->cmd_hdr.fence_id;
> +    fence.ring_idx = cmd->cmd_hdr.ring_idx;
> +
> +    trace_virtio_gpu_fence_ctrl(cmd->cmd_hdr.fence_id, cmd->cmd_hdr.type);
> +
> +    result = rutabaga_create_fence(rutabaga, &fence);
> +    CHECK_RESULT(result, cmd);
> +}
> +
> +static void
> +virtio_gpu_rutabaga_fence_cb(uint64_t user_data,
> +                             struct rutabaga_fence fence_data)
> +{
> +    VirtIOGPU *g = (VirtIOGPU *)(void*)(uintptr_t)user_data;

I don't think (void*)(uintptr_t) is necessary.

> +    struct virtio_gpu_ctrl_command *cmd, *tmp;
> +
> +    bool signaled_ctx_specific = fence_data.flags & RUTABAGA_FLAG_INFO_RING_IDX;

bool may not have enough capacity. Just using uint32_t is fine here I think.

> +
> +    QTAILQ_FOREACH_SAFE(cmd, &g->fenceq, next, tmp) {
> +        /*
> +         * Due to context specific timelines.
> +         */
> +        bool target_ctx_specific = cmd->cmd_hdr.flags &
> +                                   RUTABAGA_FLAG_INFO_RING_IDX;
> +
> +        if (signaled_ctx_specific != target_ctx_specific) {
> +            continue;
> +        }
> +
> +        if (signaled_ctx_specific &&
> +           (cmd->cmd_hdr.ring_idx != fence_data.ring_idx)) {
> +            continue;
> +        }
> +
> +        if (cmd->cmd_hdr.fence_id > fence_data.fence_id) {
> +            continue;
> +        }
> +
> +        trace_virtio_gpu_fence_resp(cmd->cmd_hdr.fence_id);
> +        virtio_gpu_ctrl_response_nodata(g, cmd, VIRTIO_GPU_RESP_OK_NODATA);
> +        QTAILQ_REMOVE(&g->fenceq, cmd, next);
> +        g_free(cmd);
> +    }
> +}
> +
> +static int virtio_gpu_rutabaga_init(VirtIOGPU *g)
> +{
> +    int result;
> +    uint64_t capset_mask;
> +    struct rutabaga_channels channels = { 0 };
> +    struct rutabaga_builder builder = { 0 };
> +
> +    GET_VIRTIO_GPU_GL(g);
> +    virtio_gpu->rutabaga = NULL;
> +
> +    if (!virtio_gpu->capset_names) {
> +        return -EINVAL;
> +    }
> +
> +    result = rutabaga_calculate_capset_mask(virtio_gpu->capset_names,
> +                                            &capset_mask);
> +    if (result) {
> +        return result;
> +    }
> +
> +    /*
> +     * rutabaga-0.1.1 is only compiled/tested with gfxstream and cross-domain
> +     * support. Future versions may change this to have more context types if
> +     * there is any interest.
> +     */
> +    if ((capset_mask & (1 << RUTABAGA_CAPSET_VIRGL)) ||
> +        (capset_mask & (1 << RUTABAGA_CAPSET_VIRGL2)) ||
> +        (capset_mask & (1 << RUTABAGA_CAPSET_VENUS)) ||
> +        (capset_mask & (1 << RUTABAGA_CAPSET_DRM))) {

Simpler:
capset_mask & (BIT(RUTABAGA_CAPSET_VIRGL) |
                BIT(RUTABAGA_CAPSET_VIRGL2) |
                BIT(RUTABAGA_CAPSET_VENUS) |
                BIT(RUTABAGA_CAPSET_DRM))

> +        return -EINVAL;
> +     }
> +
> +    builder.user_data = (uint64_t)(uintptr_t *)(void *)g;
> +    builder.fence_cb = virtio_gpu_rutabaga_fence_cb;
> +    builder.capset_mask = capset_mask;
> +
> +    if (virtio_gpu->wayland_socket_path) {
> +        if ((builder.capset_mask & (1 << RUTABAGA_CAPSET_CROSS_DOMAIN)) == 0) {
> +            return -EINVAL;
> +        }
> +
> +        channels.channels =
> +          (struct rutabaga_channel *)calloc(1, sizeof(struct rutabaga_channel));
> +        channels.num_channels = 1;
> +        channels.channels[0].channel_name = virtio_gpu->wayland_socket_path;
> +        channels.channels[0].channel_type = RUTABAGA_CHANNEL_TYPE_WAYLAND;
> +        builder.channels = &channels;
> +    }
> +
> +    result = rutabaga_init(&builder, (struct rutabaga **)&virtio_gpu->rutabaga);
> +    if (builder.capset_mask & (1 << RUTABAGA_CAPSET_CROSS_DOMAIN)) {
> +        free(channels.channels);
> +    }
> +
> +    return result;
> +}
> +
> +static int virtio_gpu_rutabaga_get_num_capsets(VirtIOGPU *g)
> +{
> +    int result = 0;

I don't think this needs to be initialized here.

> +    uint32_t num_capsets;
> +    GET_VIRTIO_GPU_GL(g);
> +
> +    if (!virtio_gpu->renderer_inited) {
> +        result = virtio_gpu_rutabaga_init(g);
> +        if (result) {
> +            qemu_log_mask(LOG_GUEST_ERROR, "Failed to init rutabaga");

Is it really a guest error? Shouldn't error_report() be used here?

> +            return 0;
> +        }
> +
> +        virtio_gpu->renderer_inited = true;
> +    }
> +
> +    GET_RUTABAGA(virtio_gpu);
> +
> +    result = rutabaga_get_num_capsets(rutabaga, &num_capsets);
> +    if (result) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "Failed to get capsets");
> +        return 0;
> +    }
> +    virtio_gpu->num_capsets = num_capsets;
> +    return (int)(num_capsets);

Explict cast is not necessary.

> +}
> +
> +static void virtio_gpu_rutabaga_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +    VirtIOGPU *g = VIRTIO_GPU(vdev);
> +    GET_VIRTIO_GPU_GL(g);
> +    struct virtio_gpu_ctrl_command *cmd;
> +
> +    if (!virtio_queue_ready(vq)) {
> +        return;
> +    }
> +
> +    if (!virtio_gpu->renderer_inited) {
> +        int result = virtio_gpu_rutabaga_init(g);
> +        if (!result) {
> +            virtio_gpu->renderer_inited = true;
> +        }
> +    }
> +
> +    if (!virtio_gpu->renderer_inited) {
> +        return;
> +    }
> +
> +    cmd = virtqueue_pop(vq, sizeof(struct virtio_gpu_ctrl_command));
> +    while (cmd) {
> +        cmd->vq = vq;
> +        cmd->error = 0;
> +        cmd->finished = false;
> +        QTAILQ_INSERT_TAIL(&g->cmdq, cmd, next);
> +        cmd = virtqueue_pop(vq, sizeof(struct virtio_gpu_ctrl_command));
> +    }
> +
> +    virtio_gpu_process_cmdq(g);
> +}
> +
> +void virtio_gpu_rutabaga_device_realize(DeviceState *qdev, Error **errp)
> +{
> +    int num_capsets;
> +    VirtIOGPUBase *bdev = VIRTIO_GPU_BASE(qdev);
> +    VirtIOGPUBaseClass *vbc = VIRTIO_GPU_BASE_GET_CLASS(bdev);
> +
> +    VirtIOGPU *gpudev = VIRTIO_GPU(qdev);
> +    VirtIOGPUClass *vgc = VIRTIO_GPU_GET_CLASS(gpudev);
> +
> +    num_capsets = virtio_gpu_rutabaga_get_num_capsets(gpudev);
> +    if (!num_capsets) {
> +        return;
> +    }
> +
> +    vbc->gl_flushed = virtio_gpu_rutabaga_gl_flushed;
> +    vgc->handle_ctrl = virtio_gpu_rutabaga_handle_ctrl;
> +    vgc->process_cmd = virtio_gpu_rutabaga_process_cmd;
> +    vgc->update_cursor_data = virtio_gpu_rutabaga_update_cursor;
> +
> +#if HOST_BIG_ENDIAN
> +    error_setg(errp, "rutabaga is not supported on bigendian platforms");
> +    return;
> +#endif
> +
> +    gpudev->parent_obj.conf.flags |= (1 << VIRTIO_GPU_FLAG_RUTABAGA_ENABLED);
> +    gpudev->parent_obj.conf.flags |= (1 << VIRTIO_GPU_FLAG_BLOB_ENABLED);
> +    gpudev->parent_obj.conf.flags
> +      |= (1 << VIRTIO_GPU_FLAG_CONTEXT_INIT_ENABLED);
> +
> +    VIRTIO_GPU_BASE(gpudev)->virtio_config.num_capsets = num_capsets;
> +    virtio_gpu_device_realize(qdev, errp);
> +}

Patch

diff --git a/hw/display/virtio-gpu-rutabaga.c b/hw/display/virtio-gpu-rutabaga.c
new file mode 100644
index 0000000000..5fd1154198
--- /dev/null
+++ b/hw/display/virtio-gpu-rutabaga.c
@@ -0,0 +1,995 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "qemu/iov.h"
+#include "trace.h"
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-gpu.h"
+#include "hw/virtio/virtio-gpu-pixman.h"
+#include "hw/virtio/virtio-iommu.h"
+
+#include <rutabaga_gfx/rutabaga_gfx_ffi.h>
+
+static int virtio_gpu_rutabaga_init(VirtIOGPU *g);
+
+#define GET_VIRTIO_GPU_GL(x)                                                  \
+        VirtIOGPUGL *virtio_gpu = VIRTIO_GPU_GL(x);                           \
+
+#define GET_RUTABAGA(x)                                                       \
+        struct rutabaga *rutabaga = (struct rutabaga *)(x->rutabaga);         \
+
+#define CHECK(condition, cmd)                                                 \
+    do {                                                                      \
+        if (!condition) {                                                     \
+            qemu_log_mask(LOG_GUEST_ERROR, "CHECK_RESULT failed in %s() %s:"  \
+                          "%d\n", __func__, __FILE__, __LINE__);              \
+            cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;                          \
+            return;                                                           \
+       }                                                                      \
+    } while (0)
+
+#define CHECK_RESULT(result, cmd) CHECK(result == 0, cmd)
+
+static void
+virtio_gpu_rutabaga_update_cursor(VirtIOGPU *g, struct virtio_gpu_scanout *s,
+                                  uint32_t resource_id)
+{
+    struct virtio_gpu_simple_resource *res;
+    struct rutabaga_transfer transfer = { 0 };
+    struct iovec transfer_iovec;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    res = virtio_gpu_find_resource(g, resource_id);
+    if (!res) {
+        return;
+    }
+
+    if (res->width != s->current_cursor->width ||
+        res->height != s->current_cursor->height) {
+        return;
+    }
+
+    transfer.x = 0;
+    transfer.y = 0;
+    transfer.z = 0;
+    transfer.w = res->width;
+    transfer.h = res->height;
+    transfer.d = 1;
+
+    transfer_iovec.iov_base = (void *)s->current_cursor->data;
+    transfer_iovec.iov_len = res->width * res->height * 4;
+
+    rutabaga_resource_transfer_read(rutabaga, 0,
+                                    resource_id, &transfer,
+                                    &transfer_iovec);
+}
+
+static void
+virtio_gpu_rutabaga_gl_flushed(VirtIOGPUBase *b)
+{
+    VirtIOGPU *g = VIRTIO_GPU(b);
+    virtio_gpu_process_cmdq(g);
+}
+
+static void
+rutabaga_cmd_create_resource_2d(VirtIOGPU *g,
+                                struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct rutabaga_create_3d rc_3d = { 0 };
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_create_2d c2d;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(c2d);
+    trace_virtio_gpu_cmd_res_create_2d(c2d.resource_id, c2d.format,
+                                       c2d.width, c2d.height);
+
+    rc_3d.target = 2;
+    rc_3d.format = c2d.format;
+    rc_3d.bind = (1 << 1);
+    rc_3d.width = c2d.width;
+    rc_3d.height = c2d.height;
+    rc_3d.depth = 1;
+    rc_3d.array_size = 1;
+    rc_3d.last_level = 0;
+    rc_3d.nr_samples = 0;
+    rc_3d.flags = VIRTIO_GPU_RESOURCE_FLAG_Y_0_TOP;
+
+    result = rutabaga_resource_create_3d(rutabaga, c2d.resource_id, &rc_3d);
+    CHECK_RESULT(result, cmd);
+
+    res = g_new0(struct virtio_gpu_simple_resource, 1);
+    res->width = c2d.width;
+    res->height = c2d.height;
+    res->format = c2d.format;
+    res->resource_id = c2d.resource_id;
+
+    QTAILQ_INSERT_HEAD(&g->reslist, res, next);
+}
+
+static void
+rutabaga_cmd_create_resource_3d(VirtIOGPU *g,
+                                struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct rutabaga_create_3d rc_3d = { 0 };
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_create_3d c3d;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(c3d);
+
+    trace_virtio_gpu_cmd_res_create_3d(c3d.resource_id, c3d.format,
+                                       c3d.width, c3d.height, c3d.depth);
+
+    rc_3d.target = c3d.target;
+    rc_3d.format = c3d.format;
+    rc_3d.bind = c3d.bind;
+    rc_3d.width = c3d.width;
+    rc_3d.height = c3d.height;
+    rc_3d.depth = c3d.depth;
+    rc_3d.array_size = c3d.array_size;
+    rc_3d.last_level = c3d.last_level;
+    rc_3d.nr_samples = c3d.nr_samples;
+    rc_3d.flags = c3d.flags;
+
+    result = rutabaga_resource_create_3d(rutabaga, c3d.resource_id, &rc_3d);
+    CHECK_RESULT(result, cmd);
+
+    res = g_new0(struct virtio_gpu_simple_resource, 1);
+    res->width = c3d.width;
+    res->height = c3d.height;
+    res->format = c3d.format;
+    res->resource_id = c3d.resource_id;
+
+    QTAILQ_INSERT_HEAD(&g->reslist, res, next);
+}
+
+static int32_t rutabaga_handle_unmap(VirtIOGPU *g,
+                                     struct virtio_gpu_simple_resource *res)
+{
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    res->mapped = NULL;
+    return rutabaga_resource_unmap(rutabaga, res->resource_id);
+}
+
+static void
+rutabaga_cmd_resource_unref(VirtIOGPU *g,
+                            struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_unref unref;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(unref);
+
+    trace_virtio_gpu_cmd_res_unref(unref.resource_id);
+
+    res = virtio_gpu_find_resource(g, unref.resource_id);
+    CHECK(res, cmd);
+
+    result = rutabaga_resource_unref(rutabaga, unref.resource_id);
+    CHECK_RESULT(result, cmd);
+
+    if (res->image) {
+        pixman_image_unref(res->image);
+    }
+
+    if (res->mapped) {
+        result = rutabaga_handle_unmap(g, res);
+        CHECK(result, cmd);
+    }
+
+    QTAILQ_REMOVE(&g->reslist, res, next);
+    g_free(res);
+}
+
+static void
+rutabaga_cmd_context_create(VirtIOGPU *g,
+                            struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_ctx_create cc;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(cc);
+    trace_virtio_gpu_cmd_ctx_create(cc.hdr.ctx_id,
+                                    cc.debug_name);
+
+    result = rutabaga_context_create(rutabaga, cc.hdr.ctx_id, cc.context_init,
+                                     cc.debug_name, cc.nlen);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_context_destroy(VirtIOGPU *g,
+                             struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_ctx_destroy cd;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(cd);
+    trace_virtio_gpu_cmd_ctx_destroy(cd.hdr.ctx_id);
+
+    result = rutabaga_context_destroy(rutabaga, cd.hdr.ctx_id);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_resource_flush(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result, i;
+    struct virtio_gpu_scanout *scanout = NULL;
+    struct virtio_gpu_simple_resource *res;
+    struct rutabaga_transfer transfer = { 0 };
+    struct iovec transfer_iovec;
+    struct virtio_gpu_resource_flush rf;
+    bool found = false;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(rf);
+    trace_virtio_gpu_cmd_res_flush(rf.resource_id,
+                                   rf.r.width, rf.r.height, rf.r.x, rf.r.y);
+
+    res = virtio_gpu_find_resource(g, rf.resource_id);
+    CHECK(res, cmd);
+
+    for (i = 0; i < g->parent_obj.conf.max_outputs; i++) {
+        scanout = &g->parent_obj.scanout[i];
+        if (i == res->scanout_bitmask) {
+            found = true;
+            break;
+        }
+    }
+
+    if (!found) {
+        return;
+    }
+
+    transfer.x = 0;
+    transfer.y = 0;
+    transfer.z = 0;
+    transfer.w = res->width;
+    transfer.h = res->height;
+    transfer.d = 1;
+
+    transfer_iovec.iov_base = (void *)pixman_image_get_data(res->image);
+    transfer_iovec.iov_len = res->width * res->height * 4;
+
+    result = rutabaga_resource_transfer_read(rutabaga, 0,
+                                             rf.resource_id, &transfer,
+                                             &transfer_iovec);
+    CHECK_RESULT(result, cmd);
+    dpy_gfx_update_full(scanout->con);
+}
+
+static void
+rutabaga_cmd_set_scanout(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
+{
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_scanout *scanout = NULL;
+    struct virtio_gpu_set_scanout ss;
+
+    VIRTIO_GPU_FILL_CMD(ss);
+    trace_virtio_gpu_cmd_set_scanout(ss.scanout_id, ss.resource_id,
+                                     ss.r.width, ss.r.height, ss.r.x, ss.r.y);
+
+    scanout = &g->parent_obj.scanout[ss.scanout_id];
+    g->parent_obj.enable = 1;
+
+    res = virtio_gpu_find_resource(g, ss.resource_id);
+    CHECK(res, cmd);
+
+    if (!res->image) {
+        pixman_format_code_t pformat;
+        pformat = virtio_gpu_get_pixman_format(res->format);
+        CHECK(pformat, cmd);
+
+        res->image = pixman_image_create_bits(pformat,
+                                              res->width,
+                                              res->height,
+                                              NULL, 0);
+        CHECK(res->image, cmd);
+        pixman_image_ref(res->image);
+    }
+
+    /* realloc the surface ptr */
+    scanout->ds = qemu_create_displaysurface_pixman(res->image);
+    dpy_gfx_replace_surface(scanout->con, NULL);
+    dpy_gfx_replace_surface(scanout->con, scanout->ds);
+    res->scanout_bitmask = ss.scanout_id;
+}
+
+static void
+rutabaga_cmd_submit_3d(VirtIOGPU *g,
+                       struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_cmd_submit cs;
+    void *buf;
+    size_t s;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(cs);
+    trace_virtio_gpu_cmd_ctx_submit(cs.hdr.ctx_id, cs.size);
+
+    buf = g_malloc(cs.size);
+    s = iov_to_buf(cmd->elem.out_sg, cmd->elem.out_num,
+                   sizeof(cs), buf, cs.size);
+    if (s != cs.size) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: size mismatch (%zd/%d)",
+                      __func__, s, cs.size);
+        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
+        goto out;
+    }
+
+    result = rutabaga_submit_command(rutabaga, cs.hdr.ctx_id, buf, cs.size);
+    CHECK_RESULT(result, cmd);
+
+out:
+    g_free(buf);
+}
+
+static void
+rutabaga_cmd_transfer_to_host_2d(VirtIOGPU *g,
+                                 struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct rutabaga_transfer transfer = { 0 };
+    struct virtio_gpu_transfer_to_host_2d t2d;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(t2d);
+    trace_virtio_gpu_cmd_res_xfer_toh_2d(t2d.resource_id);
+
+    transfer.x = t2d.r.x;
+    transfer.y = t2d.r.y;
+    transfer.z = 0;
+    transfer.w = t2d.r.width;
+    transfer.h = t2d.r.height;
+    transfer.d = 1;
+
+    result = rutabaga_resource_transfer_write(rutabaga, 0, t2d.resource_id,
+                                              &transfer);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_transfer_to_host_3d(VirtIOGPU *g,
+                                 struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct rutabaga_transfer transfer = { 0 };
+    struct virtio_gpu_transfer_host_3d t3d;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(t3d);
+    trace_virtio_gpu_cmd_res_xfer_toh_3d(t3d.resource_id);
+
+    transfer.x = t3d.box.x;
+    transfer.y = t3d.box.y;
+    transfer.z = t3d.box.z;
+    transfer.w = t3d.box.w;
+    transfer.h = t3d.box.h;
+    transfer.d = t3d.box.d;
+    transfer.level = t3d.level;
+    transfer.stride = t3d.stride;
+    transfer.layer_stride = t3d.layer_stride;
+    transfer.offset = t3d.offset;
+
+    result = rutabaga_resource_transfer_write(rutabaga, t3d.hdr.ctx_id,
+                                              t3d.resource_id, &transfer);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_transfer_from_host_3d(VirtIOGPU *g,
+                                   struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct rutabaga_transfer transfer = { 0 };
+    struct virtio_gpu_transfer_host_3d t3d;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(t3d);
+    trace_virtio_gpu_cmd_res_xfer_fromh_3d(t3d.resource_id);
+
+    transfer.x = t3d.box.x;
+    transfer.y = t3d.box.y;
+    transfer.z = t3d.box.z;
+    transfer.w = t3d.box.w;
+    transfer.h = t3d.box.h;
+    transfer.d = t3d.box.d;
+    transfer.level = t3d.level;
+    transfer.stride = t3d.stride;
+    transfer.layer_stride = t3d.layer_stride;
+    transfer.offset = t3d.offset;
+
+    result = rutabaga_resource_transfer_read(rutabaga, t3d.hdr.ctx_id,
+                                             t3d.resource_id, &transfer, NULL);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_attach_backing(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
+{
+    struct rutabaga_iovecs vecs = { 0 };
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_attach_backing att_rb;
+    struct iovec *res_iovs;
+    uint32_t res_niov;
+    int ret;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(att_rb);
+    trace_virtio_gpu_cmd_res_back_attach(att_rb.resource_id);
+
+    res = virtio_gpu_find_resource(g, att_rb.resource_id);
+    if (!res) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",
+                      __func__, att_rb.resource_id);
+        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+        return;
+    }
+
+    if (res->iov) {
+        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+        return;
+    }
+
+    ret = virtio_gpu_create_mapping_iov(g, att_rb.nr_entries, sizeof(att_rb),
+                                        cmd, NULL, &res_iovs, &res_niov);
+    if (ret != 0) {
+        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+        return;
+    }
+
+    vecs.iovecs = res_iovs;
+    vecs.num_iovecs = res_niov;
+
+    ret = rutabaga_resource_attach_backing(rutabaga, att_rb.resource_id, &vecs);
+    if (ret != 0) {
+        virtio_gpu_cleanup_mapping_iov(g, res_iovs, res_niov);
+    }
+}
+
+static void
+rutabaga_cmd_detach_backing(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
+{
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_detach_backing detach_rb;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(detach_rb);
+    trace_virtio_gpu_cmd_res_back_detach(detach_rb.resource_id);
+
+    res = virtio_gpu_find_resource(g, detach_rb.resource_id);
+    CHECK(res, cmd);
+
+    rutabaga_resource_detach_backing(rutabaga,
+                                     detach_rb.resource_id);
+
+    virtio_gpu_cleanup_mapping(g, res);
+}
+
+static void
+rutabaga_cmd_ctx_attach_resource(VirtIOGPU *g,
+                                 struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_ctx_resource att_res;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(att_res);
+    trace_virtio_gpu_cmd_ctx_res_attach(att_res.hdr.ctx_id,
+                                        att_res.resource_id);
+
+    result = rutabaga_context_attach_resource(rutabaga, att_res.hdr.ctx_id,
+                                              att_res.resource_id);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_ctx_detach_resource(VirtIOGPU *g,
+                                 struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_ctx_resource det_res;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(det_res);
+    trace_virtio_gpu_cmd_ctx_res_detach(det_res.hdr.ctx_id,
+                                        det_res.resource_id);
+
+    result = rutabaga_context_detach_resource(rutabaga, det_res.hdr.ctx_id,
+                                              det_res.resource_id);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_get_capset_info(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_get_capset_info info;
+    struct virtio_gpu_resp_capset_info resp;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(info);
+
+    result = rutabaga_get_capset_info(rutabaga, info.capset_index,
+                                      &resp.capset_id, &resp.capset_max_version,
+                                      &resp.capset_max_size);
+    CHECK_RESULT(result, cmd);
+
+    resp.hdr.type = VIRTIO_GPU_RESP_OK_CAPSET_INFO;
+    virtio_gpu_ctrl_response(g, cmd, &resp.hdr, sizeof(resp));
+}
+
+static void
+rutabaga_cmd_get_capset(VirtIOGPU *g, struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_get_capset gc;
+    struct virtio_gpu_resp_capset *resp;
+    uint32_t capset_size;
+    uint32_t current_id;
+    bool found = false;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(gc);
+    for (uint32_t i = 0; i < virtio_gpu->num_capsets; i++) {
+        result = rutabaga_get_capset_info(rutabaga, i,
+                                          &current_id, &capset_size,
+                                          &capset_size);
+        CHECK_RESULT(result, cmd);
+
+        if (current_id == gc.capset_id) {
+            found = true;
+            break;
+        }
+    }
+
+    if (!found) {
+        qemu_log_mask(LOG_GUEST_ERROR, "capset not found!");
+        return;
+    }
+
+    resp = g_malloc0(sizeof(*resp) + capset_size);
+    resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET;
+    rutabaga_get_capset(rutabaga, gc.capset_id, gc.capset_version,
+                       (uint8_t *)resp->capset_data, capset_size);
+
+    virtio_gpu_ctrl_response(g, cmd, &resp->hdr, sizeof(*resp) + capset_size);
+    g_free(resp);
+}
+
+static void
+rutabaga_cmd_resource_create_blob(VirtIOGPU *g,
+                                  struct virtio_gpu_ctrl_command *cmd)
+{
+    int result;
+    struct rutabaga_iovecs vecs = { 0 };
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_create_blob cblob;
+    struct rutabaga_create_blob rc_blob = { 0 };
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(cblob);
+    trace_virtio_gpu_cmd_res_create_blob(cblob.resource_id, cblob.size);
+
+    CHECK(cblob.resource_id != 0, cmd);
+
+    res = g_new0(struct virtio_gpu_simple_resource, 1);
+    QTAILQ_INSERT_HEAD(&g->reslist, res, next);
+
+    res->resource_id = cblob.resource_id;
+    res->blob_size = cblob.size;
+
+    if (cblob.blob_mem != VIRTIO_GPU_BLOB_MEM_HOST3D) {
+        result = virtio_gpu_create_mapping_iov(g, cblob.nr_entries,
+                                               sizeof(cblob), cmd, &res->addrs,
+                                               &res->iov, &res->iov_cnt);
+        CHECK_RESULT(result, cmd);
+    }
+
+    rc_blob.blob_id = cblob.blob_id;
+    rc_blob.blob_mem = cblob.blob_mem;
+    rc_blob.blob_flags = cblob.blob_flags;
+    rc_blob.size = cblob.size;
+
+    vecs.iovecs = res->iov;
+    vecs.num_iovecs = res->iov_cnt;
+
+    result = rutabaga_resource_create_blob(rutabaga, cblob.hdr.ctx_id,
+                                           cblob.resource_id, &rc_blob, &vecs,
+                                           NULL);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+rutabaga_cmd_resource_map_blob(VirtIOGPU *g,
+                               struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_simple_resource *res;
+    struct rutabaga_mapping mapping = { 0 };
+    struct virtio_gpu_resource_map_blob mblob;
+    struct virtio_gpu_resp_map_info resp;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(mblob);
+
+    CHECK(mblob.resource_id != 0, cmd);
+
+    res = virtio_gpu_find_resource(g, mblob.resource_id);
+    CHECK(res, cmd);
+
+    result = rutabaga_resource_map(rutabaga, mblob.resource_id, &mapping);
+    CHECK_RESULT(result, cmd);
+
+    memset(&resp, 0, sizeof(resp));
+    resp.hdr.type = VIRTIO_GPU_RESP_OK_MAP_INFO;
+    result = rutabaga_resource_map_info(rutabaga, mblob.resource_id,
+                                        &resp.map_info);
+
+    CHECK_RESULT(result, cmd);
+    virtio_gpu_ctrl_response(g, cmd, &resp.hdr, sizeof(resp));
+}
+
+static void
+rutabaga_cmd_resource_unmap_blob(VirtIOGPU *g,
+                                 struct virtio_gpu_ctrl_command *cmd)
+{
+    int32_t result;
+    struct virtio_gpu_simple_resource *res;
+    struct virtio_gpu_resource_unmap_blob ublob;
+
+    VIRTIO_GPU_FILL_CMD(ublob);
+
+    CHECK(ublob.resource_id != 0, cmd);
+
+    res = virtio_gpu_find_resource(g, ublob.resource_id);
+    CHECK(res, cmd);
+
+    result = rutabaga_handle_unmap(g, res);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+virtio_gpu_rutabaga_process_cmd(VirtIOGPU *g,
+                                struct virtio_gpu_ctrl_command *cmd)
+{
+    struct rutabaga_fence fence = { 0 };
+    int32_t result;
+
+    GET_VIRTIO_GPU_GL(g);
+    GET_RUTABAGA(virtio_gpu);
+
+    VIRTIO_GPU_FILL_CMD(cmd->cmd_hdr);
+
+    switch (cmd->cmd_hdr.type) {
+    case VIRTIO_GPU_CMD_CTX_CREATE:
+        rutabaga_cmd_context_create(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_CTX_DESTROY:
+        rutabaga_cmd_context_destroy(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_CREATE_2D:
+        rutabaga_cmd_create_resource_2d(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_CREATE_3D:
+        rutabaga_cmd_create_resource_3d(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_SUBMIT_3D:
+        rutabaga_cmd_submit_3d(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D:
+        rutabaga_cmd_transfer_to_host_2d(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_TRANSFER_TO_HOST_3D:
+        rutabaga_cmd_transfer_to_host_3d(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_TRANSFER_FROM_HOST_3D:
+        rutabaga_cmd_transfer_from_host_3d(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING:
+        rutabaga_cmd_attach_backing(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING:
+        rutabaga_cmd_detach_backing(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_SET_SCANOUT:
+        rutabaga_cmd_set_scanout(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_FLUSH:
+        rutabaga_cmd_resource_flush(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_UNREF:
+        rutabaga_cmd_resource_unref(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_CTX_ATTACH_RESOURCE:
+        rutabaga_cmd_ctx_attach_resource(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_CTX_DETACH_RESOURCE:
+        rutabaga_cmd_ctx_detach_resource(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_GET_CAPSET_INFO:
+        rutabaga_cmd_get_capset_info(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_GET_CAPSET:
+        rutabaga_cmd_get_capset(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_GET_DISPLAY_INFO:
+        virtio_gpu_get_display_info(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_GET_EDID:
+        virtio_gpu_get_edid(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB:
+        rutabaga_cmd_resource_create_blob(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_MAP_BLOB:
+        rutabaga_cmd_resource_map_blob(g, cmd);
+        break;
+    case VIRTIO_GPU_CMD_RESOURCE_UNMAP_BLOB:
+        rutabaga_cmd_resource_unmap_blob(g, cmd);
+        break;
+    default:
+        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+        break;
+    }
+
+    if (cmd->finished) {
+        return;
+    }
+    if (cmd->error) {
+        fprintf(stderr, "%s: ctrl 0x%x, error 0x%x\n", __func__,
+                cmd->cmd_hdr.type, cmd->error);
+        virtio_gpu_ctrl_response_nodata(g, cmd, cmd->error);
+        return;
+    }
+    if (!(cmd->cmd_hdr.flags & VIRTIO_GPU_FLAG_FENCE)) {
+        virtio_gpu_ctrl_response_nodata(g, cmd, VIRTIO_GPU_RESP_OK_NODATA);
+        return;
+    }
+
+    fence.flags = cmd->cmd_hdr.flags;
+    fence.ctx_id = cmd->cmd_hdr.ctx_id;
+    fence.fence_id = cmd->cmd_hdr.fence_id;
+    fence.ring_idx = cmd->cmd_hdr.ring_idx;
+
+    trace_virtio_gpu_fence_ctrl(cmd->cmd_hdr.fence_id, cmd->cmd_hdr.type);
+
+    result = rutabaga_create_fence(rutabaga, &fence);
+    CHECK_RESULT(result, cmd);
+}
+
+static void
+virtio_gpu_rutabaga_fence_cb(uint64_t user_data,
+                             struct rutabaga_fence fence_data)
+{
+    VirtIOGPU *g = (VirtIOGPU *)(void*)(uintptr_t)user_data;
+    struct virtio_gpu_ctrl_command *cmd, *tmp;
+
+    bool signaled_ctx_specific = fence_data.flags & RUTABAGA_FLAG_INFO_RING_IDX;
+
+    QTAILQ_FOREACH_SAFE(cmd, &g->fenceq, next, tmp) {
+        /*
+         * Due to context specific timelines.
+         */
+        bool target_ctx_specific = cmd->cmd_hdr.flags &
+                                   RUTABAGA_FLAG_INFO_RING_IDX;
+
+        if (signaled_ctx_specific != target_ctx_specific) {
+            continue;
+        }
+
+        if (signaled_ctx_specific &&
+           (cmd->cmd_hdr.ring_idx != fence_data.ring_idx)) {
+            continue;
+        }
+
+        if (cmd->cmd_hdr.fence_id > fence_data.fence_id) {
+            continue;
+        }
+
+        trace_virtio_gpu_fence_resp(cmd->cmd_hdr.fence_id);
+        virtio_gpu_ctrl_response_nodata(g, cmd, VIRTIO_GPU_RESP_OK_NODATA);
+        QTAILQ_REMOVE(&g->fenceq, cmd, next);
+        g_free(cmd);
+    }
+}
+
+static int virtio_gpu_rutabaga_init(VirtIOGPU *g)
+{
+    int result;
+    uint64_t capset_mask;
+    struct rutabaga_channels channels = { 0 };
+    struct rutabaga_builder builder = { 0 };
+
+    GET_VIRTIO_GPU_GL(g);
+    virtio_gpu->rutabaga = NULL;
+
+    if (!virtio_gpu->capset_names) {
+        return -EINVAL;
+    }
+
+    result = rutabaga_calculate_capset_mask(virtio_gpu->capset_names,
+                                            &capset_mask);
+    if (result) {
+        return result;
+    }
+
+    /*
+     * rutabaga-0.1.1 is only compiled/tested with gfxstream and cross-domain
+     * support. Future versions may change this to have more context types if
+     * there is any interest.
+     */
+    if ((capset_mask & (1 << RUTABAGA_CAPSET_VIRGL)) ||
+        (capset_mask & (1 << RUTABAGA_CAPSET_VIRGL2)) ||
+        (capset_mask & (1 << RUTABAGA_CAPSET_VENUS)) ||
+        (capset_mask & (1 << RUTABAGA_CAPSET_DRM))) {
+        return -EINVAL;
+     }
+
+    builder.user_data = (uint64_t)(uintptr_t *)(void *)g;
+    builder.fence_cb = virtio_gpu_rutabaga_fence_cb;
+    builder.capset_mask = capset_mask;
+
+    if (virtio_gpu->wayland_socket_path) {
+        if ((builder.capset_mask & (1 << RUTABAGA_CAPSET_CROSS_DOMAIN)) == 0) {
+            return -EINVAL;
+        }
+
+        channels.channels =
+          (struct rutabaga_channel *)calloc(1, sizeof(struct rutabaga_channel));
+        channels.num_channels = 1;
+        channels.channels[0].channel_name = virtio_gpu->wayland_socket_path;
+        channels.channels[0].channel_type = RUTABAGA_CHANNEL_TYPE_WAYLAND;
+        builder.channels = &channels;
+    }
+
+    result = rutabaga_init(&builder, (struct rutabaga **)&virtio_gpu->rutabaga);
+    if (builder.capset_mask & (1 << RUTABAGA_CAPSET_CROSS_DOMAIN)) {
+        free(channels.channels);
+    }
+
+    return result;
+}
+
+static int virtio_gpu_rutabaga_get_num_capsets(VirtIOGPU *g)
+{
+    int result = 0;
+    uint32_t num_capsets;
+    GET_VIRTIO_GPU_GL(g);
+
+    if (!virtio_gpu->renderer_inited) {
+        result = virtio_gpu_rutabaga_init(g);
+        if (result) {
+            qemu_log_mask(LOG_GUEST_ERROR, "Failed to init rutabaga");
+            return 0;
+        }
+
+        virtio_gpu->renderer_inited = true;
+    }
+
+    GET_RUTABAGA(virtio_gpu);
+
+    result = rutabaga_get_num_capsets(rutabaga, &num_capsets);
+    if (result) {
+        qemu_log_mask(LOG_GUEST_ERROR, "Failed to get capsets");
+        return 0;
+    }
+    virtio_gpu->num_capsets = num_capsets;
+    return (int)(num_capsets);
+}
+
+static void virtio_gpu_rutabaga_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOGPU *g = VIRTIO_GPU(vdev);
+    GET_VIRTIO_GPU_GL(g);
+    struct virtio_gpu_ctrl_command *cmd;
+
+    if (!virtio_queue_ready(vq)) {
+        return;
+    }
+
+    if (!virtio_gpu->renderer_inited) {
+        int result = virtio_gpu_rutabaga_init(g);
+        if (!result) {
+            virtio_gpu->renderer_inited = true;
+        }
+    }
+
+    if (!virtio_gpu->renderer_inited) {
+        return;
+    }
+
+    cmd = virtqueue_pop(vq, sizeof(struct virtio_gpu_ctrl_command));
+    while (cmd) {
+        cmd->vq = vq;
+        cmd->error = 0;
+        cmd->finished = false;
+        QTAILQ_INSERT_TAIL(&g->cmdq, cmd, next);
+        cmd = virtqueue_pop(vq, sizeof(struct virtio_gpu_ctrl_command));
+    }
+
+    virtio_gpu_process_cmdq(g);
+}
+
+void virtio_gpu_rutabaga_device_realize(DeviceState *qdev, Error **errp)
+{
+    int num_capsets;
+    VirtIOGPUBase *bdev = VIRTIO_GPU_BASE(qdev);
+    VirtIOGPUBaseClass *vbc = VIRTIO_GPU_BASE_GET_CLASS(bdev);
+
+    VirtIOGPU *gpudev = VIRTIO_GPU(qdev);
+    VirtIOGPUClass *vgc = VIRTIO_GPU_GET_CLASS(gpudev);
+
+    num_capsets = virtio_gpu_rutabaga_get_num_capsets(gpudev);
+    if (!num_capsets) {
+        return;
+    }
+
+    vbc->gl_flushed = virtio_gpu_rutabaga_gl_flushed;
+    vgc->handle_ctrl = virtio_gpu_rutabaga_handle_ctrl;
+    vgc->process_cmd = virtio_gpu_rutabaga_process_cmd;
+    vgc->update_cursor_data = virtio_gpu_rutabaga_update_cursor;
+
+#if HOST_BIG_ENDIAN
+    error_setg(errp, "rutabaga is not supported on bigendian platforms");
+    return;
+#endif
+
+    gpudev->parent_obj.conf.flags |= (1 << VIRTIO_GPU_FLAG_RUTABAGA_ENABLED);
+    gpudev->parent_obj.conf.flags |= (1 << VIRTIO_GPU_FLAG_BLOB_ENABLED);
+    gpudev->parent_obj.conf.flags
+      |= (1 << VIRTIO_GPU_FLAG_CONTEXT_INIT_ENABLED);
+
+    VIRTIO_GPU_BASE(gpudev)->virtio_config.num_capsets = num_capsets;
+    virtio_gpu_device_realize(qdev, errp);
+}