It will not be needed for reads and writes if the HBA provides a sglist.
In addition, this lets scsi-disk refuse commands with an excessive
allocation length, as well as limit memory on usual well-behaved guests.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
hw/scsi-disk.c | 44 +++++++++++++++++++++++++++++++++-----------
1 files changed, 33 insertions(+), 11 deletions(-)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index d0ac31e..4a01e0f 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -54,6 +54,7 @@ typedef struct SCSIDiskReq {
/* Both sector and sector_count are in terms of qemu 512 byte blocks. */
uint64_t sector;
uint32_t sector_count;
+ uint32_t buflen;
struct iovec iov;
QEMUIOVector qiov;
uint32_t status;
@@ -75,13 +76,15 @@ struct SCSIDiskState
};
static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type);
-static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf);
+static int scsi_disk_emulate_command(SCSIDiskReq *r);
static void scsi_free_request(SCSIRequest *req)
{
SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
- qemu_vfree(r->iov.iov_base);
+ if (r->iov.iov_base) {
+ qemu_vfree(r->iov.iov_base);
+ }
}
/* Helper function for command completion with sense. */
@@ -107,7 +110,13 @@ static void scsi_cancel_io(SCSIRequest *req)
static uint32_t scsi_init_iovec(SCSIDiskReq *r)
{
- r->iov.iov_len = MIN(r->sector_count * 512, SCSI_DMA_BUF_SIZE);
+ SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
+
+ if (!r->iov.iov_base) {
+ r->buflen = SCSI_DMA_BUF_SIZE;
+ r->iov.iov_base = qemu_blockalign(s->bs, r->buflen);
+ }
+ r->iov.iov_len = MIN(r->sector_count * 512, r->buflen);
qemu_iovec_init_external(&r->qiov, &r->iov, 1);
return r->qiov.size / 512;
}
@@ -314,7 +323,7 @@ static void scsi_dma_restart_bh(void *opaque)
scsi_write_data(&r->req);
break;
case SCSI_REQ_STATUS_RETRY_FLUSH:
- ret = scsi_disk_emulate_command(r, r->iov.iov_base);
+ ret = scsi_disk_emulate_command(r);
if (ret == 0) {
scsi_req_complete(&r->req, GOOD);
}
@@ -808,13 +817,31 @@ static int scsi_disk_emulate_read_toc(SCSIRequest *req,
uint8_t *outbuf)
return toclen;
}
-static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf)
+static int scsi_disk_emulate_command(SCSIDiskReq *r)
{
SCSIRequest *req = &r->req;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
uint64_t nb_sectors;
+ uint8_t *outbuf;
int buflen = 0;
+ if (!r->iov.iov_base) {
+ /*
+ * FIXME: we shouldn't return anything bigger than 4k, but the code
+ * requires the buffer to be as big as req->cmd.xfer in several
+ * places. So, do not allow CDBs with a very large ALLOCATION
+ * LENGTH. The real fix would be to modify scsi_read_data and
+ * dma_buf_read, so that they return data beyond the buflen
+ * as all zeros.
+ */
+ if (req->cmd.xfer > 65536) {
+ goto illegal_request;
+ }
+ r->buflen = MAX(4096, req->cmd.xfer);
+ r->iov.iov_base = qemu_blockalign(s->bs, r->buflen);
+ }
+
+ outbuf = r->iov.iov_base;
switch (req->cmd.buf[0]) {
case TEST_UNIT_READY:
if (!bdrv_is_inserted(s->bs))
@@ -965,11 +992,9 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t
*buf)
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
int32_t len;
uint8_t command;
- uint8_t *outbuf;
int rc;
command = buf[0];
- outbuf = (uint8_t *)r->iov.iov_base;
DPRINTF("Command: lun=%d tag=0x%x data=0x%02x", req->lun, req->tag,
buf[0]);
#ifdef DEBUG_SCSI
@@ -998,7 +1023,7 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t
*buf)
case GET_CONFIGURATION:
case SERVICE_ACTION_IN_16:
case VERIFY_10:
- rc = scsi_disk_emulate_command(r, outbuf);
+ rc = scsi_disk_emulate_command(r);
if (rc < 0) {
return 0;
}
@@ -1228,11 +1253,8 @@ static SCSIRequest *scsi_new_request(SCSIDevice *d,
uint32_t tag,
{
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
SCSIRequest *req;
- SCSIDiskReq *r;
req = scsi_req_alloc(&scsi_disk_reqops, &s->qdev, tag, lun, hba_private);
- r = DO_UPCAST(SCSIDiskReq, req, req);
- r->iov.iov_base = qemu_blockalign(s->bs, SCSI_DMA_BUF_SIZE);
return req;
}
--
1.7.6
