Re: [PATCH v2 12/14] KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW

[Marc Zyngier <maz@kernel.org>]

On Mon, 17 Nov 2025 22:43:23 +0000,
Oliver Upton <oupton@kernel.org> wrote:
> 
> Give the stage-2 walk similar treatment to stage-1: update the access
> flag during the table walk and do so for any walk context.
> 
> Signed-off-by: Oliver Upton <oupton@kernel.org>
> ---
>  arch/arm64/kvm/mmu.c    |  3 +++
>  arch/arm64/kvm/nested.c | 48 ++++++++++++++++++++++++++++++++++-------
>  2 files changed, 43 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 96f1786c72fe..b23d3dc8865e 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -2012,6 +2012,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		u32 esr;
>  
>  		ret = kvm_walk_nested_s2(vcpu, fault_ipa, &nested_trans);
> +		if (ret == -EAGAIN)
> +			return 1;

Err. This is returning with the srcu lock held. Can't be a good idea.

Also maybe an opportunity to turn the srcu_read_lock() call into a
guard, which would avoid future similar issue (and probably clean the
code a bit.

Thanks,

	M.

-- 
Jazz isn't dead. It just smells funny.