From: Marc Zyngier <marc.zyngier@arm.com> To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: Eric Auger <eric.auger@redhat.com>, Christoffer Dall <cdall@kernel.org>, Andre Przywara <Andre.Przywara@arm.com> Subject: [PATCH v2 2/2] kvm: arm/arm64: vgic-v3: Tighten synchronization for guests using v2 on v3 Date: Sun, 11 Mar 2018 12:49:56 +0000 [thread overview] Message-ID: <20180311124956.7683-3-marc.zyngier@arm.com> (raw) In-Reply-To: <20180311124956.7683-1-marc.zyngier@arm.com> On guest exit, and when using GICv2 on GICv3, we use a dsb(st) to force synchronization between the memory-mapped guest view and the system-register view that the hypervisor uses. This is incorrect, as the spec calls out the need for "a DSB whose required access type is both loads and stores with any Shareability attribute", while we're only synchronizing stores. We also lack an isb after the dsb to ensure that the latter has actually been executed before we start reading stuff from the sysregs. The fix is pretty easy: turn dsb(st) into dsb(sy), and slap an isb() just after. Cc: stable@vger.kernel.org Fixes: f68d2b1b73cc ("arm64: KVM: Implement vgic-v3 save/restore") Reviewed-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/hyp/vgic-v3-sr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c index f5c3d6d7019e..b89ce5432214 100644 --- a/virt/kvm/arm/hyp/vgic-v3-sr.c +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c @@ -215,7 +215,8 @@ void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu) * are now visible to the system register interface. */ if (!cpu_if->vgic_sre) { - dsb(st); + dsb(sy); + isb(); cpu_if->vgic_vmcr = read_gicreg(ICH_VMCR_EL2); } -- 2.14.2
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From: marc.zyngier@arm.com (Marc Zyngier) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 2/2] kvm: arm/arm64: vgic-v3: Tighten synchronization for guests using v2 on v3 Date: Sun, 11 Mar 2018 12:49:56 +0000 [thread overview] Message-ID: <20180311124956.7683-3-marc.zyngier@arm.com> (raw) In-Reply-To: <20180311124956.7683-1-marc.zyngier@arm.com> On guest exit, and when using GICv2 on GICv3, we use a dsb(st) to force synchronization between the memory-mapped guest view and the system-register view that the hypervisor uses. This is incorrect, as the spec calls out the need for "a DSB whose required access type is both loads and stores with any Shareability attribute", while we're only synchronizing stores. We also lack an isb after the dsb to ensure that the latter has actually been executed before we start reading stuff from the sysregs. The fix is pretty easy: turn dsb(st) into dsb(sy), and slap an isb() just after. Cc: stable at vger.kernel.org Fixes: f68d2b1b73cc ("arm64: KVM: Implement vgic-v3 save/restore") Reviewed-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/hyp/vgic-v3-sr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c index f5c3d6d7019e..b89ce5432214 100644 --- a/virt/kvm/arm/hyp/vgic-v3-sr.c +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c @@ -215,7 +215,8 @@ void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu) * are now visible to the system register interface. */ if (!cpu_if->vgic_sre) { - dsb(st); + dsb(sy); + isb(); cpu_if->vgic_vmcr = read_gicreg(ICH_VMCR_EL2); } -- 2.14.2
next prev parent reply other threads:[~2018-03-11 12:49 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-03-11 12:49 [PATCH v2 0/2] KVM: arm/arm64: GICv2-on-v3 fixes Marc Zyngier 2018-03-11 12:49 ` Marc Zyngier 2018-03-11 12:49 ` [PATCH v2 1/2] KVM: arm/arm64: vgic: Don't populate multiple LRs with the same vintid Marc Zyngier 2018-03-11 12:49 ` Marc Zyngier 2018-03-13 0:44 ` Christoffer Dall 2018-03-13 0:44 ` Christoffer Dall 2018-03-11 12:49 ` Marc Zyngier [this message] 2018-03-11 12:49 ` [PATCH v2 2/2] kvm: arm/arm64: vgic-v3: Tighten synchronization for guests using v2 on v3 Marc Zyngier 2018-03-13 0:45 ` Christoffer Dall 2018-03-13 0:45 ` Christoffer Dall
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