linux-kernel - Re: [PATCH v3 2/6] KVM: Bail from the dirty ring reset flow if a signal is pending

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Message-ID: <ddcfa7f2-c330-4482-98bf-98bbbc68e954@linux.intel.com>
Date: Tue, 20 May 2025 14:53:04 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
 linux-kernel@...r.kernel.org, Peter Xu <peterx@...hat.com>,
 Yan Zhao <yan.y.zhao@...el.com>, Maxim Levitsky <mlevitsk@...hat.com>,
 James Houghton <jthoughton@...gle.com>, Pankaj Gupta <pankaj.gupta@....com>
Subject: Re: [PATCH v3 2/6] KVM: Bail from the dirty ring reset flow if a
 signal is pending



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@...gle.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Binbin Wu <binbin.wu@...ux.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))