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qemu-patch-raspberry4/hw/xen_disk.c
Alex Bligh c1a88ad1f4 Xen PV backend: Disable use of O_DIRECT by default as it results in crashes. 
Due to what is almost certainly a kernel bug, writes with O_DIRECT may
continue to reference the page after the write has been marked as
completed, particularly in the case of TCP retransmit. In other
scenarios, this "merely" risks data corruption on the write, but with
Xen pages from domU are only transiently mapped into dom0's memory,
resulting in kernel panics when they are subsequently accessed.

This brings PV devices in line with emulated devices.  Removing
O_DIRECT is safe as barrier operations are now correctly passed
through.

See:
   http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html
for more details.

Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2013-04-05 15:45:15 +00:00

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/*
* xen paravirt block device backend
*
* (c) Gerd Hoffmann <kraxel@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>
#include <time.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/uio.h>
#include "hw/hw.h"
#include "hw/xen_backend.h"
#include "hw/xen_blkif.h"
#include "sysemu/blockdev.h"
/* ------------------------------------------------------------- */
static int batch_maps = 0;
static int max_requests = 32;
/* ------------------------------------------------------------- */
#define BLOCK_SIZE 512
#define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
struct PersistentGrant {
void *page;
struct XenBlkDev *blkdev;
};
typedef struct PersistentGrant PersistentGrant;
struct ioreq {
blkif_request_t req;
int16_t status;
/* parsed request */
off_t start;
QEMUIOVector v;
int presync;
int postsync;
uint8_t mapped;
/* grant mapping */
uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
int prot;
void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
void *pages;
int num_unmap;
/* aio status */
int aio_inflight;
int aio_errors;
struct XenBlkDev *blkdev;
QLIST_ENTRY(ioreq) list;
BlockAcctCookie acct;
};
struct XenBlkDev {
struct XenDevice xendev; /* must be first */
char *params;
char *mode;
char *type;
char *dev;
char *devtype;
const char *fileproto;
const char *filename;
int ring_ref;
void *sring;
int64_t file_blk;
int64_t file_size;
int protocol;
blkif_back_rings_t rings;
int more_work;
int cnt_map;
/* request lists */
QLIST_HEAD(inflight_head, ioreq) inflight;
QLIST_HEAD(finished_head, ioreq) finished;
QLIST_HEAD(freelist_head, ioreq) freelist;
int requests_total;
int requests_inflight;
int requests_finished;
/* Persistent grants extension */
gboolean feature_persistent;
GTree *persistent_gnts;
unsigned int persistent_gnt_count;
unsigned int max_grants;
/* qemu block driver */
DriveInfo *dinfo;
BlockDriverState *bs;
QEMUBH *bh;
};
/* ------------------------------------------------------------- */
static void ioreq_reset(struct ioreq *ioreq)
{
memset(&ioreq->req, 0, sizeof(ioreq->req));
ioreq->status = 0;
ioreq->start = 0;
ioreq->presync = 0;
ioreq->postsync = 0;
ioreq->mapped = 0;
memset(ioreq->domids, 0, sizeof(ioreq->domids));
memset(ioreq->refs, 0, sizeof(ioreq->refs));
ioreq->prot = 0;
memset(ioreq->page, 0, sizeof(ioreq->page));
ioreq->pages = NULL;
ioreq->aio_inflight = 0;
ioreq->aio_errors = 0;
ioreq->blkdev = NULL;
memset(&ioreq->list, 0, sizeof(ioreq->list));
memset(&ioreq->acct, 0, sizeof(ioreq->acct));
qemu_iovec_reset(&ioreq->v);
}
static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
{
uint ua = GPOINTER_TO_UINT(a);
uint ub = GPOINTER_TO_UINT(b);
return (ua > ub) - (ua < ub);
}
static void destroy_grant(gpointer pgnt)
{
PersistentGrant *grant = pgnt;
XenGnttab gnt = grant->blkdev->xendev.gnttabdev;
if (xc_gnttab_munmap(gnt, grant->page, 1) != 0) {
xen_be_printf(&grant->blkdev->xendev, 0,
"xc_gnttab_munmap failed: %s\n",
strerror(errno));
}
grant->blkdev->persistent_gnt_count--;
xen_be_printf(&grant->blkdev->xendev, 3,
"unmapped grant %p\n", grant->page);
g_free(grant);
}
static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
{
struct ioreq *ioreq = NULL;
if (QLIST_EMPTY(&blkdev->freelist)) {
if (blkdev->requests_total >= max_requests) {
goto out;
}
/* allocate new struct */
ioreq = g_malloc0(sizeof(*ioreq));
ioreq->blkdev = blkdev;
blkdev->requests_total++;
qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
} else {
/* get one from freelist */
ioreq = QLIST_FIRST(&blkdev->freelist);
QLIST_REMOVE(ioreq, list);
}
QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
blkdev->requests_inflight++;
out:
return ioreq;
}
static void ioreq_finish(struct ioreq *ioreq)
{
struct XenBlkDev *blkdev = ioreq->blkdev;
QLIST_REMOVE(ioreq, list);
QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
blkdev->requests_inflight--;
blkdev->requests_finished++;
}
static void ioreq_release(struct ioreq *ioreq, bool finish)
{
struct XenBlkDev *blkdev = ioreq->blkdev;
QLIST_REMOVE(ioreq, list);
ioreq_reset(ioreq);
ioreq->blkdev = blkdev;
QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
if (finish) {
blkdev->requests_finished--;
} else {
blkdev->requests_inflight--;
}
}
/*
* translate request into iovec + start offset
* do sanity checks along the way
*/
static int ioreq_parse(struct ioreq *ioreq)
{
struct XenBlkDev *blkdev = ioreq->blkdev;
uintptr_t mem;
size_t len;
int i;
xen_be_printf(&blkdev->xendev, 3,
"op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
ioreq->req.operation, ioreq->req.nr_segments,
ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
switch (ioreq->req.operation) {
case BLKIF_OP_READ:
ioreq->prot = PROT_WRITE; /* to memory */
break;
case BLKIF_OP_FLUSH_DISKCACHE:
ioreq->presync = 1;
if (!ioreq->req.nr_segments) {
return 0;
}
/* fall through */
case BLKIF_OP_WRITE:
ioreq->prot = PROT_READ; /* from memory */
break;
default:
xen_be_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n",
ioreq->req.operation);
goto err;
};
if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
xen_be_printf(&blkdev->xendev, 0, "error: write req for ro device\n");
goto err;
}
ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
for (i = 0; i < ioreq->req.nr_segments; i++) {
if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
xen_be_printf(&blkdev->xendev, 0, "error: nr_segments too big\n");
goto err;
}
if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
xen_be_printf(&blkdev->xendev, 0, "error: first > last sector\n");
goto err;
}
if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
xen_be_printf(&blkdev->xendev, 0, "error: page crossing\n");
goto err;
}
ioreq->domids[i] = blkdev->xendev.dom;
ioreq->refs[i] = ioreq->req.seg[i].gref;
mem = ioreq->req.seg[i].first_sect * blkdev->file_blk;
len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
qemu_iovec_add(&ioreq->v, (void*)mem, len);
}
if (ioreq->start + ioreq->v.size > blkdev->file_size) {
xen_be_printf(&blkdev->xendev, 0, "error: access beyond end of file\n");
goto err;
}
return 0;
err:
ioreq->status = BLKIF_RSP_ERROR;
return -1;
}
static void ioreq_unmap(struct ioreq *ioreq)
{
XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev;
int i;
if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
return;
}
if (batch_maps) {
if (!ioreq->pages) {
return;
}
if (xc_gnttab_munmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
strerror(errno));
}
ioreq->blkdev->cnt_map -= ioreq->num_unmap;
ioreq->pages = NULL;
} else {
for (i = 0; i < ioreq->num_unmap; i++) {
if (!ioreq->page[i]) {
continue;
}
if (xc_gnttab_munmap(gnt, ioreq->page[i], 1) != 0) {
xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
strerror(errno));
}
ioreq->blkdev->cnt_map--;
ioreq->page[i] = NULL;
}
}
ioreq->mapped = 0;
}
static int ioreq_map(struct ioreq *ioreq)
{
XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev;
uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
int i, j, new_maps = 0;
PersistentGrant *grant;
/* domids and refs variables will contain the information necessary
* to map the grants that are needed to fulfill this request.
*
* After mapping the needed grants, the page array will contain the
* memory address of each granted page in the order specified in ioreq
* (disregarding if it's a persistent grant or not).
*/
if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
return 0;
}
if (ioreq->blkdev->feature_persistent) {
for (i = 0; i < ioreq->v.niov; i++) {
grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
GUINT_TO_POINTER(ioreq->refs[i]));
if (grant != NULL) {
page[i] = grant->page;
xen_be_printf(&ioreq->blkdev->xendev, 3,
"using persistent-grant %" PRIu32 "\n",
ioreq->refs[i]);
} else {
/* Add the grant to the list of grants that
* should be mapped
*/
domids[new_maps] = ioreq->domids[i];
refs[new_maps] = ioreq->refs[i];
page[i] = NULL;
new_maps++;
}
}
/* Set the protection to RW, since grants may be reused later
* with a different protection than the one needed for this request
*/
ioreq->prot = PROT_WRITE | PROT_READ;
} else {
/* All grants in the request should be mapped */
memcpy(refs, ioreq->refs, sizeof(refs));
memcpy(domids, ioreq->domids, sizeof(domids));
memset(page, 0, sizeof(page));
new_maps = ioreq->v.niov;
}
if (batch_maps && new_maps) {
ioreq->pages = xc_gnttab_map_grant_refs
(gnt, new_maps, domids, refs, ioreq->prot);
if (ioreq->pages == NULL) {
xen_be_printf(&ioreq->blkdev->xendev, 0,
"can't map %d grant refs (%s, %d maps)\n",
new_maps, strerror(errno), ioreq->blkdev->cnt_map);
return -1;
}
for (i = 0, j = 0; i < ioreq->v.niov; i++) {
if (page[i] == NULL) {
page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
}
}
ioreq->blkdev->cnt_map += new_maps;
} else if (new_maps) {
for (i = 0; i < new_maps; i++) {
ioreq->page[i] = xc_gnttab_map_grant_ref
(gnt, domids[i], refs[i], ioreq->prot);
if (ioreq->page[i] == NULL) {
xen_be_printf(&ioreq->blkdev->xendev, 0,
"can't map grant ref %d (%s, %d maps)\n",
refs[i], strerror(errno), ioreq->blkdev->cnt_map);
ioreq_unmap(ioreq);
return -1;
}
ioreq->blkdev->cnt_map++;
}
for (i = 0, j = 0; i < ioreq->v.niov; i++) {
if (page[i] == NULL) {
page[i] = ioreq->page[j++];
}
}
}
if (ioreq->blkdev->feature_persistent) {
while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants)
&& new_maps) {
/* Go through the list of newly mapped grants and add as many
* as possible to the list of persistently mapped grants.
*
* Since we start at the end of ioreq->page(s), we only need
* to decrease new_maps to prevent this granted pages from
* being unmapped in ioreq_unmap.
*/
grant = g_malloc0(sizeof(*grant));
new_maps--;
if (batch_maps) {
grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
} else {
grant->page = ioreq->page[new_maps];
}
grant->blkdev = ioreq->blkdev;
xen_be_printf(&ioreq->blkdev->xendev, 3,
"adding grant %" PRIu32 " page: %p\n",
refs[new_maps], grant->page);
g_tree_insert(ioreq->blkdev->persistent_gnts,
GUINT_TO_POINTER(refs[new_maps]),
grant);
ioreq->blkdev->persistent_gnt_count++;
}
}
for (i = 0; i < ioreq->v.niov; i++) {
ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
}
ioreq->mapped = 1;
ioreq->num_unmap = new_maps;
return 0;
}
static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
static void qemu_aio_complete(void *opaque, int ret)
{
struct ioreq *ioreq = opaque;
if (ret != 0) {
xen_be_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n",
ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
ioreq->aio_errors++;
}
ioreq->aio_inflight--;
if (ioreq->presync) {
ioreq->presync = 0;
ioreq_runio_qemu_aio(ioreq);
return;
}
if (ioreq->aio_inflight > 0) {
return;
}
if (ioreq->postsync) {
ioreq->postsync = 0;
ioreq->aio_inflight++;
bdrv_aio_flush(ioreq->blkdev->bs, qemu_aio_complete, ioreq);
return;
}
ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
ioreq_unmap(ioreq);
ioreq_finish(ioreq);
bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
qemu_bh_schedule(ioreq->blkdev->bh);
}
static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
{
struct XenBlkDev *blkdev = ioreq->blkdev;
if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1) {
goto err_no_map;
}
ioreq->aio_inflight++;
if (ioreq->presync) {
bdrv_aio_flush(ioreq->blkdev->bs, qemu_aio_complete, ioreq);
return 0;
}
switch (ioreq->req.operation) {
case BLKIF_OP_READ:
bdrv_acct_start(blkdev->bs, &ioreq->acct, ioreq->v.size, BDRV_ACCT_READ);
ioreq->aio_inflight++;
bdrv_aio_readv(blkdev->bs, ioreq->start / BLOCK_SIZE,
&ioreq->v, ioreq->v.size / BLOCK_SIZE,
qemu_aio_complete, ioreq);
break;
case BLKIF_OP_WRITE:
case BLKIF_OP_FLUSH_DISKCACHE:
if (!ioreq->req.nr_segments) {
break;
}
bdrv_acct_start(blkdev->bs, &ioreq->acct, ioreq->v.size, BDRV_ACCT_WRITE);
ioreq->aio_inflight++;
bdrv_aio_writev(blkdev->bs, ioreq->start / BLOCK_SIZE,
&ioreq->v, ioreq->v.size / BLOCK_SIZE,
qemu_aio_complete, ioreq);
break;
default:
/* unknown operation (shouldn't happen -- parse catches this) */
goto err;
}
qemu_aio_complete(ioreq, 0);
return 0;
err:
ioreq_unmap(ioreq);
err_no_map:
ioreq_finish(ioreq);
ioreq->status = BLKIF_RSP_ERROR;
return -1;
}
static int blk_send_response_one(struct ioreq *ioreq)
{
struct XenBlkDev *blkdev = ioreq->blkdev;
int send_notify = 0;
int have_requests = 0;
blkif_response_t resp;
void *dst;
resp.id = ioreq->req.id;
resp.operation = ioreq->req.operation;
resp.status = ioreq->status;
/* Place on the response ring for the relevant domain. */
switch (blkdev->protocol) {
case BLKIF_PROTOCOL_NATIVE:
dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt);
break;
case BLKIF_PROTOCOL_X86_32:
dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
blkdev->rings.x86_32_part.rsp_prod_pvt);
break;
case BLKIF_PROTOCOL_X86_64:
dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
blkdev->rings.x86_64_part.rsp_prod_pvt);
break;
default:
dst = NULL;
}
memcpy(dst, &resp, sizeof(resp));
blkdev->rings.common.rsp_prod_pvt++;
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
/*
* Tail check for pending requests. Allows frontend to avoid
* notifications if requests are already in flight (lower
* overheads and promotes batching).
*/
RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
} else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
have_requests = 1;
}
if (have_requests) {
blkdev->more_work++;
}
return send_notify;
}
/* walk finished list, send outstanding responses, free requests */
static void blk_send_response_all(struct XenBlkDev *blkdev)
{
struct ioreq *ioreq;
int send_notify = 0;
while (!QLIST_EMPTY(&blkdev->finished)) {
ioreq = QLIST_FIRST(&blkdev->finished);
send_notify += blk_send_response_one(ioreq);
ioreq_release(ioreq, true);
}
if (send_notify) {
xen_be_send_notify(&blkdev->xendev);
}
}
static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
{
switch (blkdev->protocol) {
case BLKIF_PROTOCOL_NATIVE:
memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
sizeof(ioreq->req));
break;
case BLKIF_PROTOCOL_X86_32:
blkif_get_x86_32_req(&ioreq->req,
RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
break;
case BLKIF_PROTOCOL_X86_64:
blkif_get_x86_64_req(&ioreq->req,
RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
break;
}
return 0;
}
static void blk_handle_requests(struct XenBlkDev *blkdev)
{
RING_IDX rc, rp;
struct ioreq *ioreq;
blkdev->more_work = 0;
rc = blkdev->rings.common.req_cons;
rp = blkdev->rings.common.sring->req_prod;
xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
blk_send_response_all(blkdev);
while (rc != rp) {
/* pull request from ring */
if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
break;
}
ioreq = ioreq_start(blkdev);
if (ioreq == NULL) {
blkdev->more_work++;
break;
}
blk_get_request(blkdev, ioreq, rc);
blkdev->rings.common.req_cons = ++rc;
/* parse them */
if (ioreq_parse(ioreq) != 0) {
if (blk_send_response_one(ioreq)) {
xen_be_send_notify(&blkdev->xendev);
}
ioreq_release(ioreq, false);
continue;
}
ioreq_runio_qemu_aio(ioreq);
}
if (blkdev->more_work && blkdev->requests_inflight < max_requests) {
qemu_bh_schedule(blkdev->bh);
}
}
/* ------------------------------------------------------------- */
static void blk_bh(void *opaque)
{
struct XenBlkDev *blkdev = opaque;
blk_handle_requests(blkdev);
}
/*
* We need to account for the grant allocations requiring contiguous
* chunks; the worst case number would be
* max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1,
* but in order to keep things simple just use
* 2 * max_req * max_seg.
*/
#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg))
static void blk_alloc(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
QLIST_INIT(&blkdev->inflight);
QLIST_INIT(&blkdev->finished);
QLIST_INIT(&blkdev->freelist);
blkdev->bh = qemu_bh_new(blk_bh, blkdev);
if (xen_mode != XEN_EMULATE) {
batch_maps = 1;
}
if (xc_gnttab_set_max_grants(xendev->gnttabdev,
MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) {
xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n",
strerror(errno));
}
}
static int blk_init(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
int info = 0;
/* read xenstore entries */
if (blkdev->params == NULL) {
char *h = NULL;
blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
if (blkdev->params != NULL) {
h = strchr(blkdev->params, ':');
}
if (h != NULL) {
blkdev->fileproto = blkdev->params;
blkdev->filename = h+1;
*h = 0;
} else {
blkdev->fileproto = "<unset>";
blkdev->filename = blkdev->params;
}
}
if (!strcmp("aio", blkdev->fileproto)) {
blkdev->fileproto = "raw";
}
if (blkdev->mode == NULL) {
blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode");
}
if (blkdev->type == NULL) {
blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type");
}
if (blkdev->dev == NULL) {
blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev");
}
if (blkdev->devtype == NULL) {
blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type");
}
/* do we have all we need? */
if (blkdev->params == NULL ||
blkdev->mode == NULL ||
blkdev->type == NULL ||
blkdev->dev == NULL) {
goto out_error;
}
/* read-only ? */
if (strcmp(blkdev->mode, "w")) {
info |= VDISK_READONLY;
}
/* cdrom ? */
if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
info |= VDISK_CDROM;
}
blkdev->file_blk = BLOCK_SIZE;
/* fill info
* blk_connect supplies sector-size and sectors
*/
xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1);
xenstore_write_be_int(&blkdev->xendev, "info", info);
return 0;
out_error:
g_free(blkdev->params);
blkdev->params = NULL;
g_free(blkdev->mode);
blkdev->mode = NULL;
g_free(blkdev->type);
blkdev->type = NULL;
g_free(blkdev->dev);
blkdev->dev = NULL;
g_free(blkdev->devtype);
blkdev->devtype = NULL;
return -1;
}
static int blk_connect(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
int pers, index, qflags;
/* read-only ? */
qflags = BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO;
if (strcmp(blkdev->mode, "w") == 0) {
qflags |= BDRV_O_RDWR;
}
/* init qemu block driver */
index = (blkdev->xendev.dev - 202 * 256) / 16;
blkdev->dinfo = drive_get(IF_XEN, 0, index);
if (!blkdev->dinfo) {
/* setup via xenbus -> create new block driver instance */
xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
blkdev->bs = bdrv_new(blkdev->dev);
if (blkdev->bs) {
if (bdrv_open(blkdev->bs, blkdev->filename, NULL, qflags,
bdrv_find_whitelisted_format(blkdev->fileproto)) != 0) {
bdrv_delete(blkdev->bs);
blkdev->bs = NULL;
}
}
if (!blkdev->bs) {
return -1;
}
} else {
/* setup via qemu cmdline -> already setup for us */
xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n");
blkdev->bs = blkdev->dinfo->bdrv;
}
bdrv_attach_dev_nofail(blkdev->bs, blkdev);
blkdev->file_size = bdrv_getlength(blkdev->bs);
if (blkdev->file_size < 0) {
xen_be_printf(&blkdev->xendev, 1, "bdrv_getlength: %d (%s) | drv %s\n",
(int)blkdev->file_size, strerror(-blkdev->file_size),
bdrv_get_format_name(blkdev->bs) ?: "-");
blkdev->file_size = 0;
}
xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
" size %" PRId64 " (%" PRId64 " MB)\n",
blkdev->type, blkdev->fileproto, blkdev->filename,
blkdev->file_size, blkdev->file_size >> 20);
/* Fill in number of sector size and number of sectors */
xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk);
xenstore_write_be_int(&blkdev->xendev, "sectors",
blkdev->file_size / blkdev->file_blk);
if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) {
return -1;
}
if (xenstore_read_fe_int(&blkdev->xendev, "event-channel",
&blkdev->xendev.remote_port) == -1) {
return -1;
}
if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) {
blkdev->feature_persistent = FALSE;
} else {
blkdev->feature_persistent = !!pers;
}
blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
if (blkdev->xendev.protocol) {
if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
blkdev->protocol = BLKIF_PROTOCOL_X86_32;
}
if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
blkdev->protocol = BLKIF_PROTOCOL_X86_64;
}
}
blkdev->sring = xc_gnttab_map_grant_ref(blkdev->xendev.gnttabdev,
blkdev->xendev.dom,
blkdev->ring_ref,
PROT_READ | PROT_WRITE);
if (!blkdev->sring) {
return -1;
}
blkdev->cnt_map++;
switch (blkdev->protocol) {
case BLKIF_PROTOCOL_NATIVE:
{
blkif_sring_t *sring_native = blkdev->sring;
BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE);
break;
}
case BLKIF_PROTOCOL_X86_32:
{
blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE);
break;
}
case BLKIF_PROTOCOL_X86_64:
{
blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE);
break;
}
}
if (blkdev->feature_persistent) {
/* Init persistent grants */
blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST;
blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp,
NULL, NULL,
(GDestroyNotify)destroy_grant);
blkdev->persistent_gnt_count = 0;
}
xen_be_bind_evtchn(&blkdev->xendev);
xen_be_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, "
"remote port %d, local port %d\n",
blkdev->xendev.protocol, blkdev->ring_ref,
blkdev->xendev.remote_port, blkdev->xendev.local_port);
return 0;
}
static void blk_disconnect(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
if (blkdev->bs) {
if (!blkdev->dinfo) {
/* close/delete only if we created it ourself */
bdrv_close(blkdev->bs);
bdrv_detach_dev(blkdev->bs, blkdev);
bdrv_delete(blkdev->bs);
}
blkdev->bs = NULL;
}
xen_be_unbind_evtchn(&blkdev->xendev);
if (blkdev->sring) {
xc_gnttab_munmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
blkdev->cnt_map--;
blkdev->sring = NULL;
}
}
static int blk_free(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
struct ioreq *ioreq;
if (blkdev->bs || blkdev->sring) {
blk_disconnect(xendev);
}
/* Free persistent grants */
if (blkdev->feature_persistent) {
g_tree_destroy(blkdev->persistent_gnts);
}
while (!QLIST_EMPTY(&blkdev->freelist)) {
ioreq = QLIST_FIRST(&blkdev->freelist);
QLIST_REMOVE(ioreq, list);
qemu_iovec_destroy(&ioreq->v);
g_free(ioreq);
}
g_free(blkdev->params);
g_free(blkdev->mode);
g_free(blkdev->type);
g_free(blkdev->dev);
g_free(blkdev->devtype);
qemu_bh_delete(blkdev->bh);
return 0;
}
static void blk_event(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
qemu_bh_schedule(blkdev->bh);
}
struct XenDevOps xen_blkdev_ops = {
.size = sizeof(struct XenBlkDev),
.flags = DEVOPS_FLAG_NEED_GNTDEV,
.alloc = blk_alloc,
.init = blk_init,
.initialise = blk_connect,
.disconnect = blk_disconnect,
.event = blk_event,
.free = blk_free,
};
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