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.oobj-$(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