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ALSA: xen-front: Use Xen common shared buffer implementation

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Use page directory based shared buffer implementation
now available as common code for Xen frontend drivers.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Oleksandr Andrushchenko 2018-11-30 09:42:05 +02:00 committed by Boris Ostrovsky
parent 5641f19bdf
commit 58f9d806d1
7 changed files with 84 additions and 261 deletions
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1
sound/xen/Kconfig
View File

@ -5,6 +5,7 @@ config SND_XEN_FRONTEND
depends on XEN
select SND_PCM
select XEN_XENBUS_FRONTEND
select XEN_FRONT_PGDIR_SHBUF
help
Choose this option if you want to enable a para-virtualized
frontend sound driver for Xen guest OSes.

1
sound/xen/Makefile
View File

@ -3,7 +3,6 @@
snd_xen_front-objs := xen_snd_front.o \
xen_snd_front_cfg.o \
xen_snd_front_evtchnl.o \
xen_snd_front_shbuf.o \
xen_snd_front_alsa.o
obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o

7
sound/xen/xen_snd_front.c
View File

@ -16,12 +16,12 @@
#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/xen-front-pgdir-shbuf.h>
#include <xen/interface/io/sndif.h>
#include "xen_snd_front.h"
#include "xen_snd_front_alsa.h"
#include "xen_snd_front_evtchnl.h"
#include "xen_snd_front_shbuf.h"
static struct xensnd_req *
be_stream_prepare_req(struct xen_snd_front_evtchnl *evtchnl, u8 operation)
@ -82,7 +82,7 @@ int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl,
}
int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,
struct xen_snd_front_shbuf *sh_buf,
struct xen_front_pgdir_shbuf *shbuf,
u8 format, unsigned int channels,
unsigned int rate, u32 buffer_sz,
u32 period_sz)
@ -99,7 +99,8 @@ int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,
req->op.open.pcm_rate = rate;
req->op.open.buffer_sz = buffer_sz;
req->op.open.period_sz = period_sz;
req->op.open.gref_directory = xen_snd_front_shbuf_get_dir_start(sh_buf);
req->op.open.gref_directory =
xen_front_pgdir_shbuf_get_dir_start(shbuf);
mutex_unlock(&evtchnl->ring_io_lock);
ret = be_stream_do_io(evtchnl);

4
sound/xen/xen_snd_front.h
View File

@ -16,7 +16,7 @@
struct xen_snd_front_card_info;
struct xen_snd_front_evtchnl;
struct xen_snd_front_evtchnl_pair;
struct xen_snd_front_shbuf;
struct xen_front_pgdir_shbuf;
struct xensnd_query_hw_param;
struct xen_snd_front_info {
@ -35,7 +35,7 @@ int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl,
struct xensnd_query_hw_param *hw_param_resp);
int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,
struct xen_snd_front_shbuf *sh_buf,
struct xen_front_pgdir_shbuf *shbuf,
u8 format, unsigned int channels,
unsigned int rate, u32 buffer_sz,
u32 period_sz);

102
sound/xen/xen_snd_front_alsa.c
View File

@ -15,17 +15,24 @@
#include <sound/pcm_params.h>
#include <xen/xenbus.h>
#include <xen/xen-front-pgdir-shbuf.h>
#include "xen_snd_front.h"
#include "xen_snd_front_alsa.h"
#include "xen_snd_front_cfg.h"
#include "xen_snd_front_evtchnl.h"
#include "xen_snd_front_shbuf.h"
struct xen_snd_front_pcm_stream_info {
struct xen_snd_front_info *front_info;
struct xen_snd_front_evtchnl_pair *evt_pair;
struct xen_snd_front_shbuf sh_buf;
/* This is the shared buffer with its backing storage. */
struct xen_front_pgdir_shbuf shbuf;
u8 *buffer;
size_t buffer_sz;
int num_pages;
struct page **pages;
int index;
bool is_open;
@ -214,12 +221,20 @@ static void stream_clear(struct xen_snd_front_pcm_stream_info *stream)
stream->out_frames = 0;
atomic_set(&stream->hw_ptr, 0);
xen_snd_front_evtchnl_pair_clear(stream->evt_pair);
xen_snd_front_shbuf_clear(&stream->sh_buf);
memset(&stream->shbuf, 0, sizeof(stream->shbuf));
stream->buffer = NULL;
stream->buffer_sz = 0;
stream->pages = NULL;
stream->num_pages = 0;
}
static void stream_free(struct xen_snd_front_pcm_stream_info *stream)
{
xen_snd_front_shbuf_free(&stream->sh_buf);
xen_front_pgdir_shbuf_unmap(&stream->shbuf);
xen_front_pgdir_shbuf_free(&stream->shbuf);
if (stream->buffer)
free_pages_exact(stream->buffer, stream->buffer_sz);
kfree(stream->pages);
stream_clear(stream);
}
@ -421,10 +436,34 @@ static int alsa_close(struct snd_pcm_substream *substream)
return 0;
}
static int shbuf_setup_backstore(struct xen_snd_front_pcm_stream_info *stream,
size_t buffer_sz)
{
int i;
stream->buffer = alloc_pages_exact(stream->buffer_sz, GFP_KERNEL);
if (!stream->buffer)
return -ENOMEM;
stream->buffer_sz = buffer_sz;
stream->num_pages = DIV_ROUND_UP(stream->buffer_sz, PAGE_SIZE);
stream->pages = kcalloc(stream->num_pages, sizeof(struct page *),
GFP_KERNEL);
if (!stream->pages)
return -ENOMEM;
for (i = 0; i < stream->num_pages; i++)
stream->pages[i] = virt_to_page(stream->buffer + i * PAGE_SIZE);
return 0;
}
static int alsa_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
struct xen_snd_front_info *front_info = stream->front_info;
struct xen_front_pgdir_shbuf_cfg buf_cfg;
int ret;
/*
@ -432,19 +471,32 @@ static int alsa_hw_params(struct snd_pcm_substream *substream,
* so free the previously allocated shared buffer if any.
*/
stream_free(stream);
ret = shbuf_setup_backstore(stream, params_buffer_bytes(params));
if (ret < 0)
goto fail;
ret = xen_snd_front_shbuf_alloc(stream->front_info->xb_dev,
&stream->sh_buf,
params_buffer_bytes(params));
if (ret < 0) {
stream_free(stream);
dev_err(&stream->front_info->xb_dev->dev,
"Failed to allocate buffers for stream with index %d\n",
stream->index);
return ret;
}
memset(&buf_cfg, 0, sizeof(buf_cfg));
buf_cfg.xb_dev = front_info->xb_dev;
buf_cfg.pgdir = &stream->shbuf;
buf_cfg.num_pages = stream->num_pages;
buf_cfg.pages = stream->pages;
ret = xen_front_pgdir_shbuf_alloc(&buf_cfg);
if (ret < 0)
goto fail;
ret = xen_front_pgdir_shbuf_map(&stream->shbuf);
if (ret < 0)
goto fail;
return 0;
fail:
stream_free(stream);
dev_err(&front_info->xb_dev->dev,
"Failed to allocate buffers for stream with index %d\n",
stream->index);
return ret;
}
static int alsa_hw_free(struct snd_pcm_substream *substream)
@ -476,7 +528,7 @@ static int alsa_prepare(struct snd_pcm_substream *substream)
sndif_format = ret;
ret = xen_snd_front_stream_prepare(&stream->evt_pair->req,
&stream->sh_buf,
&stream->shbuf,
sndif_format,
runtime->channels,
runtime->rate,
@ -556,10 +608,10 @@ static int alsa_pb_copy_user(struct snd_pcm_substream *substream,
{
struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
if (unlikely(pos + count > stream->sh_buf.buffer_sz))
if (unlikely(pos + count > stream->buffer_sz))
return -EINVAL;
if (copy_from_user(stream->sh_buf.buffer + pos, src, count))
if (copy_from_user(stream->buffer + pos, src, count))
return -EFAULT;
return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);
@ -571,10 +623,10 @@ static int alsa_pb_copy_kernel(struct snd_pcm_substream *substream,
{
struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
if (unlikely(pos + count > stream->sh_buf.buffer_sz))
if (unlikely(pos + count > stream->buffer_sz))
return -EINVAL;
memcpy(stream->sh_buf.buffer + pos, src, count);
memcpy(stream->buffer + pos, src, count);
return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);
}
@ -586,14 +638,14 @@ static int alsa_cap_copy_user(struct snd_pcm_substream *substream,
struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
int ret;
if (unlikely(pos + count > stream->sh_buf.buffer_sz))
if (unlikely(pos + count > stream->buffer_sz))
return -EINVAL;
ret = xen_snd_front_stream_read(&stream->evt_pair->req, pos, count);
if (ret < 0)
return ret;
return copy_to_user(dst, stream->sh_buf.buffer + pos, count) ?
return copy_to_user(dst, stream->buffer + pos, count) ?
-EFAULT : 0;
}
@ -604,14 +656,14 @@ static int alsa_cap_copy_kernel(struct snd_pcm_substream *substream,
struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
int ret;
if (unlikely(pos + count > stream->sh_buf.buffer_sz))
if (unlikely(pos + count > stream->buffer_sz))
return -EINVAL;
ret = xen_snd_front_stream_read(&stream->evt_pair->req, pos, count);
if (ret < 0)
return ret;
memcpy(dst, stream->sh_buf.buffer + pos, count);
memcpy(dst, stream->buffer + pos, count);
return 0;
}
@ -622,10 +674,10 @@ static int alsa_pb_fill_silence(struct snd_pcm_substream *substream,
{
struct xen_snd_front_pcm_stream_info *stream = stream_get(substream);
if (unlikely(pos + count > stream->sh_buf.buffer_sz))
if (unlikely(pos + count > stream->buffer_sz))
return -EINVAL;
memset(stream->sh_buf.buffer + pos, 0, count);
memset(stream->buffer + pos, 0, count);
return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);
}

194
sound/xen/xen_snd_front_shbuf.c
View File

@ -1,194 +0,0 @@
// 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 <linux/kernel.h>
#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;
}

36
sound/xen/xen_snd_front_shbuf.h
View File

@ -1,36 +0,0 @@
/* 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 */