[RFC 2/5] block/nvme: Change size and alignment of IDENTIFY response buffer

[Eric Auger <eric.auger@redhat.com>]

In preparation of 64kB host page support, let's change the size
and alignment of the IDENTIFY command response buffer so that
the VFIO DMA MAP succeeds. We align on the host page size.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 block/nvme.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index e3d96f20d0..088ff1825a 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -513,19 +513,21 @@ static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
         .opcode = NVME_ADM_CMD_IDENTIFY,
         .cdw10 = cpu_to_le32(0x1),
     };
+    size_t id_size = QEMU_ALIGN_UP(sizeof(*id), qemu_real_host_page_size);
 
-    id = qemu_try_memalign(s->page_size, sizeof(*id));
+    id = qemu_try_memalign(qemu_real_host_page_size, id_size);
     if (!id) {
         error_setg(errp, "Cannot allocate buffer for identify response");
         goto out;
     }
-    r = qemu_vfio_dma_map(s->vfio, id, sizeof(*id), true, &iova);
+    r = qemu_vfio_dma_map(s->vfio, id, id_size, true, &iova);
     if (r) {
         error_setg(errp, "Cannot map buffer for DMA");
         goto out;
     }
 
-    memset(id, 0, sizeof(*id));
+    memset(id, 0, id_size);
+
     cmd.dptr.prp1 = cpu_to_le64(iova);
     if (nvme_cmd_sync(bs, s->queues[INDEX_ADMIN], &cmd)) {
         error_setg(errp, "Failed to identify controller");
@@ -547,7 +549,7 @@ static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
     s->supports_write_zeroes = !!(oncs & NVME_ONCS_WRITE_ZEROES);
     s->supports_discard = !!(oncs & NVME_ONCS_DSM);
 
-    memset(id, 0, sizeof(*id));
+    memset(id, 0, id_size);
     cmd.cdw10 = 0;
     cmd.nsid = cpu_to_le32(namespace);
     if (nvme_cmd_sync(bs, s->queues[INDEX_ADMIN], &cmd)) {
-- 
2.21.3