Qemu takes it's num_queues limit then adds the fixed queues (control and
event) to the total it will request from the kernel. So when a user
requests 128 (or qemu does it's num_queues calculation based on vCPUS
and other system limits), we hit errors due to userspace trying to setup
130 queues when vhost-scsi has a hard coded limit of 128.
This has vhost-scsi adjust it's max so we can do a total of 130 virtqueues
(128 IO and 2 fixed). For the case where the user has 128 vCPUs the guest
OS can then nicely map each IO virtqueue to a vCPU and not have the odd case
where 2 vCPUs share a virtqueue.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/vhost/scsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index ffd9e6c2ffc1..8d6b4eef554d 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -159,7 +159,7 @@ enum {
};
#define VHOST_SCSI_MAX_TARGET 256
-#define VHOST_SCSI_MAX_VQ 128
+#define VHOST_SCSI_MAX_VQ 128 + VHOST_SCSI_VQ_IO
#define VHOST_SCSI_MAX_EVENT 128
struct vhost_scsi_virtqueue {
--
2.25.1
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