Re: [RFC v1 4/4] qemu: adjust queried bar size to power-of-2

[Philippe Mathieu-Daudé]

On 6/6/23 01:50, ank...@nvidia.com wrote:

From: Ankit Agrawal <ank...@nvidia.com>

The GPU device memory is reported to the VM as a BAR. The device memory
may not be aligned to the power-of-2, but the QEMU expects the PCI BAR to
be. Align the reported device memory size to the next power-of-2 before
QEMU does an mmap.

Signed-off-by: Ankit Agrawal <ank...@nvidia.com>
---
  hw/vfio/common.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4d01ea3515..bb49200458 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -2061,7 +2061,7 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, 
VFIORegion *region,

region->vbasedev = vbasedev;

      region->flags = info->flags;
-    region->size = info->size;
+    region->size = info->size ? pow2ceil(info->size) : info->size;

       region->size = [REAL_]HOST_PAGE_ALIGN(info->size)?

      region->fd_offset = info->offset;
      region->nr = index;