[RFC,v4,11/21] vfio-user: get region info

Commit Message

John Johnson Jan. 12, 2022, 12:43 a.m. UTC

Add per-region FD to support mmap() of remote device regions

Signed-off-by: Elena Ufimtseva <[e-mail]>
Signed-off-by: John G Johnson <[e-mail]>
Signed-off-by: Jagannathan Raman <[e-mail]>
---
 hw/vfio/user-protocol.h       | 14 ++++++++++
 include/hw/vfio/vfio-common.h |  8 +++---
 hw/vfio/common.c              | 32 ++++++++++++++++++++---
 hw/vfio/user.c                | 59 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+), 6 deletions(-)

Patch

diff --git a/hw/vfio/user-protocol.h b/hw/vfio/user-protocol.h
index 4ad8f45..caa523a 100644
--- a/hw/vfio/user-protocol.h
+++ b/hw/vfio/user-protocol.h
@@ -106,4 +106,18 @@  typedef struct {
     uint32_t cap_offset;
 } VFIOUserDeviceInfo;
 
+/*
+ * VFIO_USER_DEVICE_GET_REGION_INFO
+ * imported from struct_vfio_region_info
+ */
+typedef struct {
+    VFIOUserHdr hdr;
+    uint32_t argsz;
+    uint32_t flags;
+    uint32_t index;
+    uint32_t cap_offset;
+    uint64_t size;
+    uint64_t offset;
+} VFIOUserRegionInfo;
+
 #endif /* VFIO_USER_PROTOCOL_H */
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 3eb0b19..2552557 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -56,6 +56,7 @@  typedef struct VFIORegion {
     uint32_t nr_mmaps;
     VFIOMmap *mmaps;
     uint8_t nr; /* cache the region number for debug */
+    int fd; /* fd to mmap() region */
 } VFIORegion;
 
 typedef struct VFIOMigration {
@@ -150,6 +151,7 @@  typedef struct VFIODevice {
     OnOffAuto pre_copy_dirty_page_tracking;
     VFIOProxy *proxy;
     struct vfio_region_info **regions;
+    int *regfds;
 } VFIODevice;
 
 struct VFIODeviceOps {
@@ -172,7 +174,7 @@  struct VFIODeviceOps {
 struct VFIODevIO {
     int (*get_info)(VFIODevice *vdev, struct vfio_device_info *info);
     int (*get_region_info)(VFIODevice *vdev,
-                           struct vfio_region_info *info);
+                           struct vfio_region_info *info, int *fd);
     int (*get_irq_info)(VFIODevice *vdev, struct vfio_irq_info *irq);
     int (*set_irqs)(VFIODevice *vdev, struct vfio_irq_set *irqs);
     int (*region_read)(VFIODevice *vdev, uint8_t nr, off_t off, uint32_t size,
@@ -183,8 +185,8 @@  struct VFIODevIO {
 
 #define VDEV_GET_INFO(vdev, info) \
     ((vdev)->io_ops->get_info((vdev), (info)))
-#define VDEV_GET_REGION_INFO(vdev, info) \
-    ((vdev)->io_ops->get_region_info((vdev), (info)))
+#define VDEV_GET_REGION_INFO(vdev, info, fd) \
+    ((vdev)->io_ops->get_region_info((vdev), (info), (fd)))
 #define VDEV_GET_IRQ_INFO(vdev, irq) \
     ((vdev)->io_ops->get_irq_info((vdev), (irq)))
 #define VDEV_SET_IRQS(vdev, irqs) \
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index f07023c..a50bf4b 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -40,6 +40,7 @@ 
 #include "trace.h"
 #include "qapi/error.h"
 #include "migration/migration.h"
+#include "hw/vfio/user.h"
 
 VFIOGroupList vfio_group_list =
     QLIST_HEAD_INITIALIZER(vfio_group_list);
@@ -1554,6 +1555,11 @@  int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
     region->size = info->size;
     region->fd_offset = info->offset;
     region->nr = index;
+    if (vbasedev->regfds != NULL) {
+        region->fd = vbasedev->regfds[index];
+    } else {
+        region->fd = vbasedev->fd;
+    }
 
     if (region->size) {
         region->mem = g_new0(MemoryRegion, 1);
@@ -1605,7 +1611,7 @@  int vfio_region_mmap(VFIORegion *region)
 
     for (i = 0; i < region->nr_mmaps; i++) {
         region->mmaps[i].mmap = mmap(NULL, region->mmaps[i].size, prot,
-                                     MAP_SHARED, region->vbasedev->fd,
+                                     MAP_SHARED, region->fd,
                                      region->fd_offset +
                                      region->mmaps[i].offset);
         if (region->mmaps[i].mmap == MAP_FAILED) {
@@ -2410,10 +2416,17 @@  void vfio_put_base_device(VFIODevice *vbasedev)
         int i;
 
         for (i = 0; i < vbasedev->num_regions; i++) {
+            if (vbasedev->regfds != NULL && vbasedev->regfds[i] != -1) {
+                close(vbasedev->regfds[i]);
+            }
             g_free(vbasedev->regions[i]);
         }
         g_free(vbasedev->regions);
         vbasedev->regions = NULL;
+        if (vbasedev->regfds != NULL) {
+            g_free(vbasedev->regfds);
+            vbasedev->regfds = NULL;
+        }
     }
 
     if (!vbasedev->group) {
@@ -2429,12 +2442,16 @@  int vfio_get_region_info(VFIODevice *vbasedev, int index,
                          struct vfio_region_info **info)
 {
     size_t argsz = sizeof(struct vfio_region_info);
+    int fd = -1;
     int ret;
 
     /* create region cache */
     if (vbasedev->regions == NULL) {
         vbasedev->regions = g_new0(struct vfio_region_info *,
                                    vbasedev->num_regions);
+        if (vbasedev->proxy != NULL) {
+            vbasedev->regfds = g_new0(int, vbasedev->num_regions);
+        }
     }
     /* check cache */
     if (vbasedev->regions[index] != NULL) {
@@ -2448,7 +2465,7 @@  int vfio_get_region_info(VFIODevice *vbasedev, int index,
 retry:
     (*info)->argsz = argsz;
 
-    ret = VDEV_GET_REGION_INFO(vbasedev, *info);
+    ret = VDEV_GET_REGION_INFO(vbasedev, *info, &fd);
     if (ret != 0) {
         g_free(*info);
         *info = NULL;
@@ -2458,12 +2475,19 @@  retry:
     if ((*info)->argsz > argsz) {
         argsz = (*info)->argsz;
         *info = g_realloc(*info, argsz);
+        if (fd != -1) {
+            close(fd);
+            fd = -1;
+        }
 
         goto retry;
     }
 
     /* fill cache */
     vbasedev->regions[index] = *info;
+    if (vbasedev->regfds != NULL) {
+        vbasedev->regfds[index] = fd;
+    }
 
     return 0;
 }
@@ -2623,10 +2647,12 @@  static int vfio_io_get_info(VFIODevice *vbasedev, struct vfio_device_info *info)
 }
 
 static int vfio_io_get_region_info(VFIODevice *vbasedev,
-                                   struct vfio_region_info *info)
+                                   struct vfio_region_info *info,
+                                   int *fd)
 {
     int ret;
 
+    *fd = -1;
     ret = ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, info);
 
     return ret < 0 ? -errno : ret;
diff --git a/hw/vfio/user.c b/hw/vfio/user.c
index 671c4f1..1b0c9aa 100644
--- a/hw/vfio/user.c
+++ b/hw/vfio/user.c
@@ -925,6 +925,40 @@  static int vfio_user_get_info(VFIOProxy *proxy, struct vfio_device_info *info)
     return 0;
 }
 
+static int vfio_user_get_region_info(VFIOProxy *proxy,
+                                     struct vfio_region_info *info,
+                                     VFIOUserFDs *fds)
+{
+    g_autofree VFIOUserRegionInfo *msgp = NULL;
+    uint32_t size;
+
+    /* data returned can be larger than vfio_region_info */
+    if (info->argsz < sizeof(*info)) {
+        error_printf("vfio_user_get_region_info argsz too small\n");
+        return -EINVAL;
+    }
+    if (fds != NULL && fds->send_fds != 0) {
+        error_printf("vfio_user_get_region_info can't send FDs\n");
+        return -EINVAL;
+    }
+
+    size = info->argsz + sizeof(VFIOUserHdr);
+    msgp = g_malloc0(size);
+
+    vfio_user_request_msg(&msgp->hdr, VFIO_USER_DEVICE_GET_REGION_INFO,
+                          sizeof(*msgp), 0);
+    msgp->argsz = info->argsz;
+    msgp->index = info->index;
+
+    vfio_user_send_wait(proxy, &msgp->hdr, fds, size, false);
+    if (msgp->hdr.flags & VFIO_USER_ERROR) {
+        return -msgp->hdr.error_reply;
+    }
+
+    memcpy(info, &msgp->argsz, info->argsz);
+    return 0;
+}
+
 
 /*
  * Socket-based io_ops
@@ -947,7 +981,32 @@  static int vfio_user_io_get_info(VFIODevice *vbasedev,
     return 0;
 }
 
+static int vfio_user_io_get_region_info(VFIODevice *vbasedev,
+                                        struct vfio_region_info *info,
+                                        int *fd)
+{
+    int ret;
+    VFIOUserFDs fds = { 0, 1, fd};
+
+    ret = vfio_user_get_region_info(vbasedev->proxy, info, &fds);
+    if (ret) {
+        return ret;
+    }
+
+    if (info->index > vbasedev->num_regions) {
+        return -EINVAL;
+    }
+    /* cap_offset in valid area */
+    if ((info->flags & VFIO_REGION_INFO_FLAG_CAPS) &&
+        (info->cap_offset < sizeof(*info) || info->cap_offset > info->argsz)) {
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
 VFIODevIO vfio_dev_io_sock = {
     .get_info = vfio_user_io_get_info,
+    .get_region_info = vfio_user_io_get_region_info,
 };