[PATCH-for-5.2 v2 14/25] block/nvme: Correctly initialize Admin Queue Attributes

[Philippe Mathieu-Daudé]

>From the specification chapter 3.1.8 "AQA - Admin Queue Attributes"
the Admin Submission Queue Size field is a 0’s based value:

  Admin Submission Queue Size (ASQS):

    Defines the size of the Admin Submission Queue in entries.
    Enabling a controller while this field is cleared to 00h
    produces undefined results. The minimum size of the Admin
    Submission Queue is two entries. The maximum size of the
    Admin Submission Queue is 4096 entries.
    This is a 0’s based value.

This bug has never been hit because the device initialization
uses a single command synchronously :)

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 block/nvme.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index 7285bd2e271..0902aa55428 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -789,9 +789,9 @@ static int nvme_init(BlockDriverState *bs, const char 
*device, int namespace,
         goto out;
     }
     s->queue_count = 1;
-    QEMU_BUILD_BUG_ON(NVME_QUEUE_SIZE & 0xF000);
-    regs->aqa = cpu_to_le32((NVME_QUEUE_SIZE << AQA_ACQS_SHIFT) |
-                            (NVME_QUEUE_SIZE << AQA_ASQS_SHIFT));
+    QEMU_BUILD_BUG_ON((NVME_QUEUE_SIZE - 1) & 0xF000);
+    regs->aqa = cpu_to_le32(((NVME_QUEUE_SIZE - 1) << AQA_ACQS_SHIFT) |
+                            ((NVME_QUEUE_SIZE - 1) << AQA_ASQS_SHIFT));
     regs->asq = cpu_to_le64(s->queues[INDEX_ADMIN]->sq.iova);
     regs->acq = cpu_to_le64(s->queues[INDEX_ADMIN]->cq.iova);
 
-- 
2.26.2