Abort a dirty ring reset if the current task has a pending signal, as the
hard limit of INT_MAX entries doesn't ensure KVM will respond to a signal
in a timely fashion.

Fixes: fb04a1eddb1a ("KVM: X86: Implement ring-based dirty memory tracking")
Reviewed-by: James Houghton <jthoughton@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/kvm/dirty_ring.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
index 77986f34eff8..e844e869e8c7 100644
--- a/virt/kvm/dirty_ring.c
+++ b/virt/kvm/dirty_ring.c
@@ -118,6 +118,9 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring,
 	cur_slot = cur_offset = mask = 0;
 
 	while (likely((*nr_entries_reset) < INT_MAX)) {
+		if (signal_pending(current))
+			return -EINTR;
+
 		entry = &ring->dirty_gfns[ring->reset_index & (ring->size - 1)];
 
 		if (!kvm_dirty_gfn_harvested(entry))
-- 
2.49.0.1112.g889b7c5bd8-goog

On 5/17/2025 5:35 AM, Sean Christopherson wrote:
> Abort a dirty ring reset if the current task has a pending signal, as the
> hard limit of INT_MAX entries doesn't ensure KVM will respond to a signal
> in a timely fashion.
>
> Fixes: fb04a1eddb1a ("KVM: X86: Implement ring-based dirty memory tracking")
> Reviewed-by: James Houghton <jthoughton@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>

> ---
>   virt/kvm/dirty_ring.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
> index 77986f34eff8..e844e869e8c7 100644
> --- a/virt/kvm/dirty_ring.c
> +++ b/virt/kvm/dirty_ring.c
> @@ -118,6 +118,9 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring,
>   	cur_slot = cur_offset = mask = 0;
>   
>   	while (likely((*nr_entries_reset) < INT_MAX)) {
> +		if (signal_pending(current))
> +			return -EINTR;
> +
>   		entry = &ring->dirty_gfns[ring->reset_index & (ring->size - 1)];
>   
>   		if (!kvm_dirty_gfn_harvested(entry))