On 5/5/20 10:23 AM, Laurent Vivier wrote:
On 05/05/2020 10:00, Laurent Vivier wrote:
On 04/05/2020 11:46, Philippe Mathieu-Daudé wrote:
In nvme_create_queue_pair() we create a page list using
qemu_blockalign(), then map it with qemu_vfio_dma_map():
q->prp_list_pages = qemu_blockalign0(bs, s->page_size * NVME_QUEUE_SIZE);
r = qemu_vfio_dma_map(s->vfio, q->prp_list_pages,
s->page_size * NVME_QUEUE_SIZE, ...);
With:
s->page_size = MAX(4096, 1 << (12 + ((cap >> 48) & 0xF)));
The qemu_vfio_dma_map() documentation says "The caller need
to make sure the area is aligned to page size". While we use
multiple s->page_size as alignment, it might be not sufficient
on some hosts. Use the qemu_real_host_page_size value to be
sure the host alignment is respected.
Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
Cc: Cédric Le Goater <c...@kaod.org>
Cc: David Gibson <da...@gibson.dropbear.id.au>
Cc: Laurent Vivier <lviv...@redhat.com>
---
block/nvme.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/nvme.c b/block/nvme.c
index 7b7c0cc5d6..bde0d28b39 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -627,7 +627,7 @@ static int nvme_init(BlockDriverState *bs, const char
*device, int namespace,
s->page_size = MAX(4096, 1 << (12 + ((cap >> 48) & 0xF)));
s->doorbell_scale = (4 << (((cap >> 32) & 0xF))) / sizeof(uint32_t);
- bs->bl.opt_mem_alignment = s->page_size;
+ bs->bl.opt_mem_alignment = MAX(qemu_real_host_page_size, s->page_size);
Why don't you replace directly the "4096" in s->page_size by
qemu_real_host_page_size?
I think this was the purpose of MAX(4096, ...) to align to the host page
size.
oh, I see, page_size is used for a lot of things than can be broken, and
this is what is done in bdrv_opt_mem_align() for instance, 4096 is the
sector size not the host page size.
BTW, you need the same change as in nvme_init() in
nvme_refresh_limits(), I think.
nvme_init() seems OK, but you are right, I missed
nvme_refresh_limits()... Thanks!
Thanks,
Laurent