| Message ID | 20180416062453.24743-5-andr2000@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 16/04/18 08:24, Oleksandr Andrushchenko wrote: > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > > Implement shared buffer handling according to the > para-virtualized sound device protocol at xen/interface/io/sndif.h: > - manage buffer memory > - handle granted references > - handle page directories > > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > --- > sound/xen/Makefile | 3 +- > sound/xen/xen_snd_front.c | 8 ++ > sound/xen/xen_snd_front_shbuf.c | 193 ++++++++++++++++++++++++++++++++++++++++ > sound/xen/xen_snd_front_shbuf.h | 36 ++++++++ > 4 files changed, 239 insertions(+), 1 deletion(-) > create mode 100644 sound/xen/xen_snd_front_shbuf.c > create mode 100644 sound/xen/xen_snd_front_shbuf.h > > diff --git a/sound/xen/Makefile b/sound/xen/Makefile > index 03c669984000..f028bc30af5d 100644 > --- a/sound/xen/Makefile > +++ b/sound/xen/Makefile > @@ -2,6 +2,7 @@ > > snd_xen_front-objs := xen_snd_front.o \ > xen_snd_front_cfg.o \ > - xen_snd_front_evtchnl.o > + xen_snd_front_evtchnl.o \ > + xen_snd_front_shbuf.o > > obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o > diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c > index eb46bf4070f9..0569c6c596a3 100644 > --- a/sound/xen/xen_snd_front.c > +++ b/sound/xen/xen_snd_front.c > @@ -11,6 +11,7 @@ > #include <linux/delay.h> > #include <linux/module.h> > > +#include <xen/page.h> > #include <xen/platform_pci.h> > #include <xen/xen.h> > #include <xen/xenbus.h> > @@ -186,6 +187,13 @@ static struct xenbus_driver xen_driver = { > > static int __init xen_drv_init(void) > { > + /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ > + if (XEN_PAGE_SIZE != PAGE_SIZE) { > + pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n", > + XEN_PAGE_SIZE, PAGE_SIZE); > + return -ENODEV; > + } Do you really want to print that error message on bare metal? > + > if (!xen_domain()) > return -ENODEV; > > diff --git a/sound/xen/xen_snd_front_shbuf.c b/sound/xen/xen_snd_front_shbuf.c > new file mode 100644 > index 000000000000..6845dbc7fdf5 > --- /dev/null > +++ b/sound/xen/xen_snd_front_shbuf.c > @@ -0,0 +1,193 @@ > +// SPDX-License-Identifier: GPL-2.0 OR MIT > + > +/* > + * Xen para-virtual sound device > + * > + * Copyright (C) 2016-2018 EPAM Systems Inc. > + * > + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > + */ > + > +#include <xen/xen.h> > +#include <xen/xenbus.h> > + > +#include "xen_snd_front_shbuf.h" > + > +grant_ref_t xen_snd_front_shbuf_get_dir_start(struct xen_snd_front_shbuf *buf) > +{ > + if (!buf->grefs) > + return GRANT_INVALID_REF; > + > + return buf->grefs[0]; > +} > + > +void xen_snd_front_shbuf_clear(struct xen_snd_front_shbuf *buf) > +{ > + memset(buf, 0, sizeof(*buf)); > +} > + > +void xen_snd_front_shbuf_free(struct xen_snd_front_shbuf *buf) > +{ > + int i; > + > + if (buf->grefs) { > + for (i = 0; i < buf->num_grefs; i++) > + if (buf->grefs[i] != GRANT_INVALID_REF) > + gnttab_end_foreign_access(buf->grefs[i], > + 0, 0UL); > + kfree(buf->grefs); > + } > + kfree(buf->directory); > + free_pages_exact(buf->buffer, buf->buffer_sz); > + xen_snd_front_shbuf_clear(buf); > +} > + > +/* > + * number of grant references a page can hold with respect to the > + * xensnd_page_directory header > + */ > +#define XENSND_NUM_GREFS_PER_PAGE ((XEN_PAGE_SIZE - \ > + offsetof(struct xensnd_page_directory, gref)) / \ > + sizeof(grant_ref_t)) > + > +static void fill_page_dir(struct xen_snd_front_shbuf *buf, > + int num_pages_dir) > +{ > + struct xensnd_page_directory *page_dir; > + unsigned char *ptr; > + int i, cur_gref, grefs_left, to_copy; > + > + ptr = buf->directory; > + grefs_left = buf->num_grefs - num_pages_dir; > + /* > + * skip grant references at the beginning, they are for pages granted > + * for the page directory itself > + */ > + cur_gref = num_pages_dir; > + for (i = 0; i < num_pages_dir; i++) { > + page_dir = (struct xensnd_page_directory *)ptr; > + if (grefs_left <= XENSND_NUM_GREFS_PER_PAGE) { > + to_copy = grefs_left; > + page_dir->gref_dir_next_page = GRANT_INVALID_REF; > + } else { > + to_copy = XENSND_NUM_GREFS_PER_PAGE; > + page_dir->gref_dir_next_page = buf->grefs[i + 1]; > + } > + > + memcpy(&page_dir->gref, &buf->grefs[cur_gref], > + to_copy * sizeof(grant_ref_t)); > + > + ptr += XEN_PAGE_SIZE; > + grefs_left -= to_copy; > + cur_gref += to_copy; > + } > +} > + > +static int grant_references(struct xenbus_device *xb_dev, > + struct xen_snd_front_shbuf *buf, > + int num_pages_dir, int num_pages_buffer, > + int num_grefs) > +{ > + grant_ref_t priv_gref_head; > + unsigned long frame; > + int ret, i, j, cur_ref; > + int otherend_id; > + > + ret = gnttab_alloc_grant_references(num_grefs, &priv_gref_head); > + if (ret) > + return ret; > + > + buf->num_grefs = num_grefs; > + otherend_id = xb_dev->otherend_id; > + j = 0; > + > + for (i = 0; i < num_pages_dir; i++) { > + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); > + if (cur_ref < 0) { > + ret = cur_ref; > + goto fail; > + } > + > + frame = xen_page_to_gfn(virt_to_page(buf->directory + > + XEN_PAGE_SIZE * i)); > + gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0); > + buf->grefs[j++] = cur_ref; > + } > + > + for (i = 0; i < num_pages_buffer; i++) { > + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); > + if (cur_ref < 0) { > + ret = cur_ref; > + goto fail; > + } > + > + frame = xen_page_to_gfn(virt_to_page(buf->buffer + > + XEN_PAGE_SIZE * i)); > + gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0); > + buf->grefs[j++] = cur_ref; > + } > + > + gnttab_free_grant_references(priv_gref_head); > + fill_page_dir(buf, num_pages_dir); > + return 0; > + > +fail: > + gnttab_free_grant_references(priv_gref_head); > + return ret; > +} > + > +static int alloc_int_buffers(struct xen_snd_front_shbuf *buf, > + int num_pages_dir, int num_pages_buffer, > + int num_grefs) > +{ > + buf->grefs = kcalloc(num_grefs, sizeof(*buf->grefs), GFP_KERNEL); > + if (!buf->grefs) > + return -ENOMEM; > + > + buf->directory = kcalloc(num_pages_dir, XEN_PAGE_SIZE, GFP_KERNEL); > + if (!buf->directory) > + goto fail; > + > + buf->buffer_sz = num_pages_buffer * XEN_PAGE_SIZE; > + buf->buffer = alloc_pages_exact(buf->buffer_sz, GFP_KERNEL); > + if (!buf->buffer) > + goto fail; > + > + return 0; > + > +fail: > + kfree(buf->grefs); > + buf->grefs = NULL; > + kfree(buf->directory); Why do you need to free those here? Shouldn't that be done via xen_snd_front_shbuf_free() in case of an error? Juergen
On 04/16/2018 04:39 PM, Juergen Gross wrote: > On 16/04/18 08:24, Oleksandr Andrushchenko wrote: >> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> >> Implement shared buffer handling according to the >> para-virtualized sound device protocol at xen/interface/io/sndif.h: >> - manage buffer memory >> - handle granted references >> - handle page directories >> >> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> --- >> sound/xen/Makefile | 3 +- >> sound/xen/xen_snd_front.c | 8 ++ >> sound/xen/xen_snd_front_shbuf.c | 193 ++++++++++++++++++++++++++++++++++++++++ >> sound/xen/xen_snd_front_shbuf.h | 36 ++++++++ >> 4 files changed, 239 insertions(+), 1 deletion(-) >> create mode 100644 sound/xen/xen_snd_front_shbuf.c >> create mode 100644 sound/xen/xen_snd_front_shbuf.h >> >> diff --git a/sound/xen/Makefile b/sound/xen/Makefile >> index 03c669984000..f028bc30af5d 100644 >> --- a/sound/xen/Makefile >> +++ b/sound/xen/Makefile >> @@ -2,6 +2,7 @@ >> >> snd_xen_front-objs := xen_snd_front.o \ >> xen_snd_front_cfg.o \ >> - xen_snd_front_evtchnl.o >> + xen_snd_front_evtchnl.o \ >> + xen_snd_front_shbuf.o >> >> obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o >> diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c >> index eb46bf4070f9..0569c6c596a3 100644 >> --- a/sound/xen/xen_snd_front.c >> +++ b/sound/xen/xen_snd_front.c >> @@ -11,6 +11,7 @@ >> #include <linux/delay.h> >> #include <linux/module.h> >> >> +#include <xen/page.h> >> #include <xen/platform_pci.h> >> #include <xen/xen.h> >> #include <xen/xenbus.h> >> @@ -186,6 +187,13 @@ static struct xenbus_driver xen_driver = { >> >> static int __init xen_drv_init(void) >> { >> + /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ >> + if (XEN_PAGE_SIZE != PAGE_SIZE) { >> + pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n", >> + XEN_PAGE_SIZE, PAGE_SIZE); >> + return -ENODEV; >> + } > Do you really want to print that error message on bare metal? will move it down after xen_domain/xen_has_pv_devices checks >> + >> if (!xen_domain()) >> return -ENODEV; >> >> diff --git a/sound/xen/xen_snd_front_shbuf.c b/sound/xen/xen_snd_front_shbuf.c >> new file mode 100644 >> index 000000000000..6845dbc7fdf5 >> --- /dev/null >> +++ b/sound/xen/xen_snd_front_shbuf.c >> @@ -0,0 +1,193 @@ >> +// SPDX-License-Identifier: GPL-2.0 OR MIT >> + >> +/* >> + * Xen para-virtual sound device >> + * >> + * Copyright (C) 2016-2018 EPAM Systems Inc. >> + * >> + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> + */ >> + >> +#include <xen/xen.h> >> +#include <xen/xenbus.h> >> + >> +#include "xen_snd_front_shbuf.h" >> + >> +grant_ref_t xen_snd_front_shbuf_get_dir_start(struct xen_snd_front_shbuf *buf) >> +{ >> + if (!buf->grefs) >> + return GRANT_INVALID_REF; >> + >> + return buf->grefs[0]; >> +} >> + >> +void xen_snd_front_shbuf_clear(struct xen_snd_front_shbuf *buf) >> +{ >> + memset(buf, 0, sizeof(*buf)); >> +} >> + >> +void xen_snd_front_shbuf_free(struct xen_snd_front_shbuf *buf) >> +{ >> + int i; >> + >> + if (buf->grefs) { >> + for (i = 0; i < buf->num_grefs; i++) >> + if (buf->grefs[i] != GRANT_INVALID_REF) >> + gnttab_end_foreign_access(buf->grefs[i], >> + 0, 0UL); >> + kfree(buf->grefs); >> + } >> + kfree(buf->directory); >> + free_pages_exact(buf->buffer, buf->buffer_sz); >> + xen_snd_front_shbuf_clear(buf); >> +} >> + >> +/* >> + * number of grant references a page can hold with respect to the >> + * xensnd_page_directory header >> + */ >> +#define XENSND_NUM_GREFS_PER_PAGE ((XEN_PAGE_SIZE - \ >> + offsetof(struct xensnd_page_directory, gref)) / \ >> + sizeof(grant_ref_t)) >> + >> +static void fill_page_dir(struct xen_snd_front_shbuf *buf, >> + int num_pages_dir) >> +{ >> + struct xensnd_page_directory *page_dir; >> + unsigned char *ptr; >> + int i, cur_gref, grefs_left, to_copy; >> + >> + ptr = buf->directory; >> + grefs_left = buf->num_grefs - num_pages_dir; >> + /* >> + * skip grant references at the beginning, they are for pages granted >> + * for the page directory itself >> + */ >> + cur_gref = num_pages_dir; >> + for (i = 0; i < num_pages_dir; i++) { >> + page_dir = (struct xensnd_page_directory *)ptr; >> + if (grefs_left <= XENSND_NUM_GREFS_PER_PAGE) { >> + to_copy = grefs_left; >> + page_dir->gref_dir_next_page = GRANT_INVALID_REF; >> + } else { >> + to_copy = XENSND_NUM_GREFS_PER_PAGE; >> + page_dir->gref_dir_next_page = buf->grefs[i + 1]; >> + } >> + >> + memcpy(&page_dir->gref, &buf->grefs[cur_gref], >> + to_copy * sizeof(grant_ref_t)); >> + >> + ptr += XEN_PAGE_SIZE; >> + grefs_left -= to_copy; >> + cur_gref += to_copy; >> + } >> +} >> + >> +static int grant_references(struct xenbus_device *xb_dev, >> + struct xen_snd_front_shbuf *buf, >> + int num_pages_dir, int num_pages_buffer, >> + int num_grefs) >> +{ >> + grant_ref_t priv_gref_head; >> + unsigned long frame; >> + int ret, i, j, cur_ref; >> + int otherend_id; >> + >> + ret = gnttab_alloc_grant_references(num_grefs, &priv_gref_head); >> + if (ret) >> + return ret; >> + >> + buf->num_grefs = num_grefs; >> + otherend_id = xb_dev->otherend_id; >> + j = 0; >> + >> + for (i = 0; i < num_pages_dir; i++) { >> + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); >> + if (cur_ref < 0) { >> + ret = cur_ref; >> + goto fail; >> + } >> + >> + frame = xen_page_to_gfn(virt_to_page(buf->directory + >> + XEN_PAGE_SIZE * i)); >> + gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0); >> + buf->grefs[j++] = cur_ref; >> + } >> + >> + for (i = 0; i < num_pages_buffer; i++) { >> + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); >> + if (cur_ref < 0) { >> + ret = cur_ref; >> + goto fail; >> + } >> + >> + frame = xen_page_to_gfn(virt_to_page(buf->buffer + >> + XEN_PAGE_SIZE * i)); >> + gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0); >> + buf->grefs[j++] = cur_ref; >> + } >> + >> + gnttab_free_grant_references(priv_gref_head); >> + fill_page_dir(buf, num_pages_dir); >> + return 0; >> + >> +fail: >> + gnttab_free_grant_references(priv_gref_head); >> + return ret; >> +} >> + >> +static int alloc_int_buffers(struct xen_snd_front_shbuf *buf, >> + int num_pages_dir, int num_pages_buffer, >> + int num_grefs) >> +{ >> + buf->grefs = kcalloc(num_grefs, sizeof(*buf->grefs), GFP_KERNEL); >> + if (!buf->grefs) >> + return -ENOMEM; >> + >> + buf->directory = kcalloc(num_pages_dir, XEN_PAGE_SIZE, GFP_KERNEL); >> + if (!buf->directory) >> + goto fail; >> + >> + buf->buffer_sz = num_pages_buffer * XEN_PAGE_SIZE; >> + buf->buffer = alloc_pages_exact(buf->buffer_sz, GFP_KERNEL); >> + if (!buf->buffer) >> + goto fail; >> + >> + return 0; >> + >> +fail: >> + kfree(buf->grefs); >> + buf->grefs = NULL; >> + kfree(buf->directory); > Why do you need to free those here? Shouldn't that be done via > xen_snd_front_shbuf_free() in case of an error? At this place we only allocate memory, but xen_snd_front_shbuf_free will also try to gnttab_end_foreign_access if buf->grefs != NULL. > Juergen
On 17/04/18 11:22, Oleksandr Andrushchenko wrote: > On 04/16/2018 04:39 PM, Juergen Gross wrote: >> On 16/04/18 08:24, Oleksandr Andrushchenko wrote: >>> +static int alloc_int_buffers(struct xen_snd_front_shbuf *buf, >>> + int num_pages_dir, int num_pages_buffer, >>> + int num_grefs) >>> +{ >>> + buf->grefs = kcalloc(num_grefs, sizeof(*buf->grefs), GFP_KERNEL); >>> + if (!buf->grefs) >>> + return -ENOMEM; >>> + >>> + buf->directory = kcalloc(num_pages_dir, XEN_PAGE_SIZE, GFP_KERNEL); >>> + if (!buf->directory) >>> + goto fail; >>> + >>> + buf->buffer_sz = num_pages_buffer * XEN_PAGE_SIZE; >>> + buf->buffer = alloc_pages_exact(buf->buffer_sz, GFP_KERNEL); >>> + if (!buf->buffer) >>> + goto fail; >>> + >>> + return 0; >>> + >>> +fail: >>> + kfree(buf->grefs); >>> + buf->grefs = NULL; >>> + kfree(buf->directory); >> Why do you need to free those here? Shouldn't that be done via >> xen_snd_front_shbuf_free() in case of an error? > At this place we only allocate memory, but xen_snd_front_shbuf_free > will also try to gnttab_end_foreign_access if buf->grefs != NULL. Okay. Juergen
diff --git a/sound/xen/Makefile b/sound/xen/Makefile index 03c669984000..f028bc30af5d 100644 --- a/sound/xen/Makefile +++ b/sound/xen/Makefile @@ -2,6 +2,7 @@ snd_xen_front-objs := xen_snd_front.o \ xen_snd_front_cfg.o \ - xen_snd_front_evtchnl.o + xen_snd_front_evtchnl.o \ + xen_snd_front_shbuf.o obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c index eb46bf4070f9..0569c6c596a3 100644 --- a/sound/xen/xen_snd_front.c +++ b/sound/xen/xen_snd_front.c @@ -11,6 +11,7 @@ #include <linux/delay.h> #include <linux/module.h> +#include <xen/page.h> #include <xen/platform_pci.h> #include <xen/xen.h> #include <xen/xenbus.h> @@ -186,6 +187,13 @@ static struct xenbus_driver xen_driver = { static int __init xen_drv_init(void) { + /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ + if (XEN_PAGE_SIZE != PAGE_SIZE) { + pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n", + XEN_PAGE_SIZE, PAGE_SIZE); + return -ENODEV; + } + if (!xen_domain()) return -ENODEV; diff --git a/sound/xen/xen_snd_front_shbuf.c b/sound/xen/xen_snd_front_shbuf.c new file mode 100644 index 000000000000..6845dbc7fdf5 --- /dev/null +++ b/sound/xen/xen_snd_front_shbuf.c @@ -0,0 +1,193 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT + +/* + * Xen para-virtual sound device + * + * Copyright (C) 2016-2018 EPAM Systems Inc. + * + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> + */ + +#include <xen/xen.h> +#include <xen/xenbus.h> + +#include "xen_snd_front_shbuf.h" + +grant_ref_t xen_snd_front_shbuf_get_dir_start(struct xen_snd_front_shbuf *buf) +{ + if (!buf->grefs) + return GRANT_INVALID_REF; + + return buf->grefs[0]; +} + +void xen_snd_front_shbuf_clear(struct xen_snd_front_shbuf *buf) +{ + memset(buf, 0, sizeof(*buf)); +} + +void xen_snd_front_shbuf_free(struct xen_snd_front_shbuf *buf) +{ + int i; + + if (buf->grefs) { + for (i = 0; i < buf->num_grefs; i++) + if (buf->grefs[i] != GRANT_INVALID_REF) + gnttab_end_foreign_access(buf->grefs[i], + 0, 0UL); + kfree(buf->grefs); + } + kfree(buf->directory); + free_pages_exact(buf->buffer, buf->buffer_sz); + xen_snd_front_shbuf_clear(buf); +} + +/* + * number of grant references a page can hold with respect to the + * xensnd_page_directory header + */ +#define XENSND_NUM_GREFS_PER_PAGE ((XEN_PAGE_SIZE - \ + offsetof(struct xensnd_page_directory, gref)) / \ + sizeof(grant_ref_t)) + +static void fill_page_dir(struct xen_snd_front_shbuf *buf, + int num_pages_dir) +{ + struct xensnd_page_directory *page_dir; + unsigned char *ptr; + int i, cur_gref, grefs_left, to_copy; + + ptr = buf->directory; + grefs_left = buf->num_grefs - num_pages_dir; + /* + * skip grant references at the beginning, they are for pages granted + * for the page directory itself + */ + cur_gref = num_pages_dir; + for (i = 0; i < num_pages_dir; i++) { + page_dir = (struct xensnd_page_directory *)ptr; + if (grefs_left <= XENSND_NUM_GREFS_PER_PAGE) { + to_copy = grefs_left; + page_dir->gref_dir_next_page = GRANT_INVALID_REF; + } else { + to_copy = XENSND_NUM_GREFS_PER_PAGE; + page_dir->gref_dir_next_page = buf->grefs[i + 1]; + } + + memcpy(&page_dir->gref, &buf->grefs[cur_gref], + to_copy * sizeof(grant_ref_t)); + + ptr += XEN_PAGE_SIZE; + grefs_left -= to_copy; + cur_gref += to_copy; + } +} + +static int grant_references(struct xenbus_device *xb_dev, + struct xen_snd_front_shbuf *buf, + int num_pages_dir, int num_pages_buffer, + int num_grefs) +{ + grant_ref_t priv_gref_head; + unsigned long frame; + int ret, i, j, cur_ref; + int otherend_id; + + ret = gnttab_alloc_grant_references(num_grefs, &priv_gref_head); + if (ret) + return ret; + + buf->num_grefs = num_grefs; + otherend_id = xb_dev->otherend_id; + j = 0; + + for (i = 0; i < num_pages_dir; i++) { + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); + if (cur_ref < 0) { + ret = cur_ref; + goto fail; + } + + frame = xen_page_to_gfn(virt_to_page(buf->directory + + XEN_PAGE_SIZE * i)); + gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0); + buf->grefs[j++] = cur_ref; + } + + for (i = 0; i < num_pages_buffer; i++) { + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); + if (cur_ref < 0) { + ret = cur_ref; + goto fail; + } + + frame = xen_page_to_gfn(virt_to_page(buf->buffer + + XEN_PAGE_SIZE * i)); + gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0); + buf->grefs[j++] = cur_ref; + } + + gnttab_free_grant_references(priv_gref_head); + fill_page_dir(buf, num_pages_dir); + return 0; + +fail: + gnttab_free_grant_references(priv_gref_head); + return ret; +} + +static int alloc_int_buffers(struct xen_snd_front_shbuf *buf, + int num_pages_dir, int num_pages_buffer, + int num_grefs) +{ + buf->grefs = kcalloc(num_grefs, sizeof(*buf->grefs), GFP_KERNEL); + if (!buf->grefs) + return -ENOMEM; + + buf->directory = kcalloc(num_pages_dir, XEN_PAGE_SIZE, GFP_KERNEL); + if (!buf->directory) + goto fail; + + buf->buffer_sz = num_pages_buffer * XEN_PAGE_SIZE; + buf->buffer = alloc_pages_exact(buf->buffer_sz, GFP_KERNEL); + if (!buf->buffer) + goto fail; + + return 0; + +fail: + kfree(buf->grefs); + buf->grefs = NULL; + kfree(buf->directory); + buf->directory = NULL; + return -ENOMEM; +} + +int xen_snd_front_shbuf_alloc(struct xenbus_device *xb_dev, + struct xen_snd_front_shbuf *buf, + unsigned int buffer_sz) +{ + int num_pages_buffer, num_pages_dir, num_grefs; + int ret; + + xen_snd_front_shbuf_clear(buf); + + num_pages_buffer = DIV_ROUND_UP(buffer_sz, XEN_PAGE_SIZE); + /* number of pages the page directory consumes itself */ + num_pages_dir = DIV_ROUND_UP(num_pages_buffer, + XENSND_NUM_GREFS_PER_PAGE); + num_grefs = num_pages_buffer + num_pages_dir; + + ret = alloc_int_buffers(buf, num_pages_dir, + num_pages_buffer, num_grefs); + if (ret < 0) + return ret; + + ret = grant_references(xb_dev, buf, num_pages_dir, num_pages_buffer, + num_grefs); + if (ret < 0) + return ret; + + fill_page_dir(buf, num_pages_dir); + return 0; +} diff --git a/sound/xen/xen_snd_front_shbuf.h b/sound/xen/xen_snd_front_shbuf.h new file mode 100644 index 000000000000..d28e97c47b2c --- /dev/null +++ b/sound/xen/xen_snd_front_shbuf.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 OR MIT */ + +/* + * Xen para-virtual sound device + * + * Copyright (C) 2016-2018 EPAM Systems Inc. + * + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> + */ + +#ifndef __XEN_SND_FRONT_SHBUF_H +#define __XEN_SND_FRONT_SHBUF_H + +#include <xen/grant_table.h> + +#include "xen_snd_front_evtchnl.h" + +struct xen_snd_front_shbuf { + int num_grefs; + grant_ref_t *grefs; + u8 *directory; + u8 *buffer; + size_t buffer_sz; +}; + +grant_ref_t xen_snd_front_shbuf_get_dir_start(struct xen_snd_front_shbuf *buf); + +int xen_snd_front_shbuf_alloc(struct xenbus_device *xb_dev, + struct xen_snd_front_shbuf *buf, + unsigned int buffer_sz); + +void xen_snd_front_shbuf_clear(struct xen_snd_front_shbuf *buf); + +void xen_snd_front_shbuf_free(struct xen_snd_front_shbuf *buf); + +#endif /* __XEN_SND_FRONT_SHBUF_H */