From: Christoffer Dall <christoffer.dall@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 6/7] arm64: KVM: vgic-v3: Prevent the guest from messing with ICC_SRE_EL1
Date: Tue, 24 May 2016 14:49:31 +0200 [thread overview]
Message-ID: <20160524124931.GF3582@cbox> (raw)
In-Reply-To: <1464007023-11736-7-git-send-email-marc.zyngier@arm.com>
On Mon, May 23, 2016 at 01:37:02PM +0100, Marc Zyngier wrote:
> Both our GIC emulations are "strict", in the sense that we either
> emulate a GICv2 or a GICv3, and not a GICv3 with GICv2 legacy
> support.
>
> But when running on a GICv3 host, we still allow the guest to
> tinker with the ICC_SRE_EL1 register during its time slice:
> it can switch SRE off, observe that it is off, and yet on the
> next world switch, find the SRE bit to be set again. Not very
> nice.
>
> An obvious solution is to always trap accesses to ICC_SRE_EL1
> (by clearing ICC_SRE_EL2.Enable), and to let the handler return
> the programmed value on a read, or ignore the write.
>
> That way, the guest can always observe that our GICv3 is SRE==1
> only.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 6/7] arm64: KVM: vgic-v3: Prevent the guest from messing with ICC_SRE_EL1
Date: Tue, 24 May 2016 14:49:31 +0200 [thread overview]
Message-ID: <20160524124931.GF3582@cbox> (raw)
In-Reply-To: <1464007023-11736-7-git-send-email-marc.zyngier@arm.com>
On Mon, May 23, 2016 at 01:37:02PM +0100, Marc Zyngier wrote:
> Both our GIC emulations are "strict", in the sense that we either
> emulate a GICv2 or a GICv3, and not a GICv3 with GICv2 legacy
> support.
>
> But when running on a GICv3 host, we still allow the guest to
> tinker with the ICC_SRE_EL1 register during its time slice:
> it can switch SRE off, observe that it is off, and yet on the
> next world switch, find the SRE bit to be set again. Not very
> nice.
>
> An obvious solution is to always trap accesses to ICC_SRE_EL1
> (by clearing ICC_SRE_EL2.Enable), and to let the handler return
> the programmed value on a read, or ignore the write.
>
> That way, the guest can always observe that our GICv3 is SRE==1
> only.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
next prev parent reply other threads:[~2016-05-24 12:49 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-23 12:36 [PATCH 0/7] vgic fixes for 4.7-rc1 Marc Zyngier
2016-05-23 12:36 ` Marc Zyngier
2016-05-23 12:36 ` [PATCH 1/7] KVM: arm/arm64: vgic-v2: Clear all dirty LRs Marc Zyngier
2016-05-23 12:36 ` Marc Zyngier
2016-05-23 12:36 ` [PATCH 2/7] KVM: arm/arm64: vgic-v3: " Marc Zyngier
2016-05-23 12:36 ` Marc Zyngier
2016-05-23 12:36 ` [PATCH 3/7] KVM: arm/arm64: vgic-v2: Always resample level interrupts Marc Zyngier
2016-05-23 12:36 ` Marc Zyngier
2016-05-23 14:19 ` Christoffer Dall
2016-05-23 14:19 ` Christoffer Dall
2016-05-23 14:41 ` Marc Zyngier
2016-05-23 14:41 ` Marc Zyngier
2016-05-23 12:37 ` [PATCH 4/7] KVM: arm/arm64: vgic-v3: " Marc Zyngier
2016-05-23 12:37 ` Marc Zyngier
2016-05-23 14:19 ` Christoffer Dall
2016-05-23 14:19 ` Christoffer Dall
2016-05-23 12:37 ` [PATCH 5/7] arm64: KVM: Make ICC_SRE_EL1 access return the configured SRE value Marc Zyngier
2016-05-23 12:37 ` Marc Zyngier
2016-05-24 12:45 ` Christoffer Dall
2016-05-24 12:45 ` Christoffer Dall
2016-05-23 12:37 ` [PATCH 6/7] arm64: KVM: vgic-v3: Prevent the guest from messing with ICC_SRE_EL1 Marc Zyngier
2016-05-23 12:37 ` Marc Zyngier
2016-05-24 12:49 ` Christoffer Dall [this message]
2016-05-24 12:49 ` Christoffer Dall
2016-05-23 12:37 ` [PATCH 7/7] arm64: KVM: vgic-v3: Relax synchronization when SRE==1 Marc Zyngier
2016-05-23 12:37 ` Marc Zyngier
2016-05-24 12:52 ` Christoffer Dall
2016-05-24 12:52 ` Christoffer Dall
2016-05-24 13:02 ` Marc Zyngier
2016-05-24 13:02 ` Marc Zyngier
2016-05-24 13:18 ` Christoffer Dall
2016-05-24 13:18 ` Christoffer Dall
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