scsi: make io_timeout configurable

The current code sets an infinite timeout on SG_IO requests,
causing the guest to stall if the host experiences a frame
loss.
This patch adds an 'io_timeout' parameter for SCSIDevice to
make the SG_IO timeout configurable, and also shortens the
default timeout to 30 seconds to avoid infinite stalls.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Message-Id: <20201116183114.55703-3-hare@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 18 insertions, 9 deletions

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index ed52fcd49f..c4016d1cfc 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2624,7 +2624,7 @@ static int get_device_type(SCSIDiskState *s)
     cmd[4] = sizeof(buf);
 
     ret = scsi_SG_IO_FROM_DEV(s->qdev.conf.blk, cmd, sizeof(cmd),
-                              buf, sizeof(buf));
+                              buf, sizeof(buf), s->qdev.io_timeout);
     if (ret < 0) {
         return -1;
     }
@@ -2785,7 +2785,7 @@ static BlockAIOCB *scsi_block_do_sgio(SCSIBlockReq *req,
     /* The rest is as in scsi-generic.c.  */
     io_header->mx_sb_len = sizeof(r->req.sense);
     io_header->sbp = r->req.sense;
-    io_header->timeout = UINT_MAX;
+    io_header->timeout = s->qdev.io_timeout * 1000;
     io_header->usr_ptr = r;
     io_header->flags |= SG_FLAG_DIRECT_IO;
 
@@ -3103,6 +3103,8 @@ static Property scsi_block_properties[] = {
                        DEFAULT_MAX_IO_SIZE),
     DEFINE_PROP_INT32("scsi_version", SCSIDiskState, qdev.default_scsi_version,
                       -1),
+    DEFINE_PROP_UINT32("io_timeout", SCSIDiskState, qdev.io_timeout,
+                       DEFAULT_IO_TIMEOUT),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index ab220141f5..3dd3ccd097 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -115,6 +115,8 @@ static int execute_command(BlockBackend *blk,
                            SCSIGenericReq *r, int direction,
                            BlockCompletionFunc *complete)
 {
+    SCSIDevice *s = r->req.dev;
+
     r->io_header.interface_id = 'S';
     r->io_header.dxfer_direction = direction;
     r->io_header.dxferp = r->buf;
@@ -123,7 +125,7 @@ static int execute_command(BlockBackend *blk,
     r->io_header.cmd_len = r->req.cmd.len;
     r->io_header.mx_sb_len = sizeof(r->req.sense);
     r->io_header.sbp = r->req.sense;
-    r->io_header.timeout = MAX_UINT;
+    r->io_header.timeout = s->io_timeout * 1000;
     r->io_header.usr_ptr = r;
     r->io_header.flags |= SG_FLAG_DIRECT_IO;
 
@@ -506,7 +508,7 @@ static int read_naa_id(const uint8_t *p, uint64_t *p_wwn)
 }
 
 int scsi_SG_IO_FROM_DEV(BlockBackend *blk, uint8_t *cmd, uint8_t cmd_size,
-                        uint8_t *buf, uint8_t buf_size)
+                        uint8_t *buf, uint8_t buf_size, uint32_t timeout)
 {
     sg_io_hdr_t io_header;
     uint8_t sensebuf[8];
@@ -521,7 +523,7 @@ int scsi_SG_IO_FROM_DEV(BlockBackend *blk, uint8_t *cmd, uint8_t cmd_size,
     io_header.cmd_len = cmd_size;
     io_header.mx_sb_len = sizeof(sensebuf);
     io_header.sbp = sensebuf;
-    io_header.timeout = 6000; /* XXX */
+    io_header.timeout = timeout * 1000;
 
     ret = blk_ioctl(blk, SG_IO, &io_header);
     if (ret < 0 || io_header.driver_status || io_header.host_status) {
@@ -551,7 +553,7 @@ static void scsi_generic_set_vpd_bl_emulation(SCSIDevice *s)
     cmd[4] = sizeof(buf);
 
     ret = scsi_SG_IO_FROM_DEV(s->conf.blk, cmd, sizeof(cmd),
-                              buf, sizeof(buf));
+                              buf, sizeof(buf), s->io_timeout);
     if (ret < 0) {
         /*
          * Do not assume anything if we can't retrieve the
@@ -587,7 +589,7 @@ static void scsi_generic_read_device_identification(SCSIDevice *s)
     cmd[4] = sizeof(buf);
 
     ret = scsi_SG_IO_FROM_DEV(s->conf.blk, cmd, sizeof(cmd),
-                              buf, sizeof(buf));
+                              buf, sizeof(buf), s->io_timeout);
     if (ret < 0) {
         return;
     }
@@ -638,7 +640,7 @@ static int get_stream_blocksize(BlockBackend *blk)
     cmd[0] = MODE_SENSE;
     cmd[4] = sizeof(buf);
 
-    ret = scsi_SG_IO_FROM_DEV(blk, cmd, sizeof(cmd), buf, sizeof(buf));
+    ret = scsi_SG_IO_FROM_DEV(blk, cmd, sizeof(cmd), buf, sizeof(buf), 6);
     if (ret < 0) {
         return -1;
     }
@@ -728,6 +730,7 @@ static void scsi_generic_realize(SCSIDevice *s, Error **errp)
 
     /* Only used by scsi-block, but initialize it nevertheless to be clean.  */
     s->default_scsi_version = -1;
+    s->io_timeout = DEFAULT_IO_TIMEOUT;
     scsi_generic_read_device_inquiry(s);
 }
 
@@ -751,6 +754,8 @@ static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun,
 static Property scsi_generic_properties[] = {
     DEFINE_PROP_DRIVE("drive", SCSIDevice, conf.blk),
     DEFINE_PROP_BOOL("share-rw", SCSIDevice, conf.share_rw, false),
+    DEFINE_PROP_UINT32("io_timeout", SCSIDevice, io_timeout,
+                       DEFAULT_IO_TIMEOUT),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
index 09fa5c9d2a..a8ef59c0f4 100644
--- a/include/hw/scsi/scsi.h
+++ b/include/hw/scsi/scsi.h
@@ -18,6 +18,7 @@ typedef struct SCSIReqOps SCSIReqOps;
 
 #define SCSI_SENSE_BUF_SIZE_OLD 96
 #define SCSI_SENSE_BUF_SIZE 252
+#define DEFAULT_IO_TIMEOUT 30
 
 struct SCSIRequest {
     SCSIBus           *bus;
@@ -84,6 +85,7 @@ struct SCSIDevice
     uint64_t port_wwn;
     int scsi_version;
     int default_scsi_version;
+    uint32_t io_timeout;
     bool needs_vpd_bl_emulation;
     bool hba_supports_iothread;
 };
@@ -188,7 +190,7 @@ void scsi_device_unit_attention_reported(SCSIDevice *dev);
 void scsi_generic_read_device_inquiry(SCSIDevice *dev);
 int scsi_device_get_sense(SCSIDevice *dev, uint8_t *buf, int len, bool fixed);
 int scsi_SG_IO_FROM_DEV(BlockBackend *blk, uint8_t *cmd, uint8_t cmd_size,
-                        uint8_t *buf, uint8_t buf_size);
+                        uint8_t *buf, uint8_t buf_size, uint32_t timeout);
 SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int target, int lun);
 SCSIDevice *scsi_device_get(SCSIBus *bus, int channel, int target, int lun);