Re: [PATCH 3/5] KVM: arm64: vgic-v3: Don't advertise ICC_CTLR_EL1.SEIS

From: Alexandru Elisei <alexandru.elisei@arm.com>
To: Marc Zyngier <maz@kernel.org>,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Cc: James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Eric Auger <eric.auger@redhat.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	kernel-team@android.com,
	Alexandru Elisei <alexandru.elisei@arm.com>
Subject: Re: [PATCH 3/5] KVM: arm64: vgic-v3: Don't advertise ICC_CTLR_EL1.SEIS
Date: Mon, 4 Oct 2021 13:49:31 +0100	[thread overview]
Message-ID: <7b629634-0d0d-5601-3a64-c418ef2fc1e6@arm.com> (raw)
In-Reply-To: <20210924082542.2766170-4-maz@kernel.org>

Hi Marc,

On 9/24/21 09:25, Marc Zyngier wrote:
> Since we are trapping all sysreg accesses when ICH_VTR_EL2.SEIS
> is set, and that we never deliver an SError when emulating
> any of the GICv3 sysregs, don't advertise ICC_CTLR_EL1.SEIS.

Makes sense, we don't emulate it, so don't advertise it. Checked
__vgic_v3_write_ctlr(), and we only allow the guest to modify EOI mode and which
register is responsible for determining the binary point for the interrupt priority.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>

Thanks,

Alex

>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/hyp/vgic-v3-sr.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/vgic-v3-sr.c b/arch/arm64/kvm/hyp/vgic-v3-sr.c
> index 39f8f7f9227c..b3b50de496a3 100644
> --- a/arch/arm64/kvm/hyp/vgic-v3-sr.c
> +++ b/arch/arm64/kvm/hyp/vgic-v3-sr.c
> @@ -987,8 +987,6 @@ static void __vgic_v3_read_ctlr(struct kvm_vcpu *vcpu, u32 vmcr, int rt)
>  	val = ((vtr >> 29) & 7) << ICC_CTLR_EL1_PRI_BITS_SHIFT;
>  	/* IDbits */
>  	val |= ((vtr >> 23) & 7) << ICC_CTLR_EL1_ID_BITS_SHIFT;
> -	/* SEIS */
> -	val |= ((vtr >> 22) & 1) << ICC_CTLR_EL1_SEIS_SHIFT;
>  	/* A3V */
>  	val |= ((vtr >> 21) & 1) << ICC_CTLR_EL1_A3V_SHIFT;
>  	/* EOImode */