[PATCH v2 1/2] KVM: arm64: Fix dirty logging detection in ring-only mode

[Gavin Shan]

On 10/30/26 3:52 AM, Wei-Lin Chang wrote:
> When checking whether a memslot has dirty logging enabled, the
> KVM_MEM_LOG_DIRTY_PAGES flag is the source of truth. Previously in
> memslot_is_logging() we were testing the dirty bitmap only and did not
> consider dirty ring.
> 
> With the ring and no bitmap, a logged memslot can still get block
> mappings, so guest writes to most of a block are never logged and a
> migration can copy stale memory.
> 
> Fix this by using kvm_slot_dirty_track_enabled() instead which checks
> KVM_MEM_LOG_DIRTY_PAGES, within memslot_is_logging().
> 
> Fixes: 9cb1096f8590 ("KVM: arm64: Enable ring-based dirty memory tracking")
> Reviewed-by: Fuad Tabba <fuad.tabba at linux.dev>
> Tested-by: Fuad Tabba <fuad.tabba at linux.dev>
> Signed-off-by: Wei-Lin Chang <weilin.chang at arm.com>
> Cc: stable at vger.kernel.org
> ---
>   arch/arm64/kvm/mmu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
Reviewed-by: Gavin Shan <gshan at redhat.com>