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 <[email protected]> --- 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 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
