From: Marc Zyngier <maz@kernel.org>
To: 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>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Oliver Upton <oupton@google.com>, Will Deacon <will@kernel.org>,
Fuad Tabba <tabba@google.com>,
Quentin Perret <qperret@google.com>,
Mark Brown <broonie@kernel.org>,
Reiji Watanabe <reijiw@google.com>,
kernel-team@android.com, stable@vger.kernel.org
Subject: [PATCH v2 01/19] KVM: arm64: Always start with clearing SVE flag on load
Date: Fri, 10 Jun 2022 10:28:20 +0100 [thread overview]
Message-ID: <20220610092838.1205755-2-maz@kernel.org> (raw)
In-Reply-To: <20220610092838.1205755-1-maz@kernel.org>
On each vcpu load, we set the KVM_ARM64_HOST_SVE_ENABLED
flag if SVE is enabled for EL0 on the host. This is used to restore
the correct state on vpcu put.
However, it appears that nothing ever clears this flag. Once
set, it will stick until the vcpu is destroyed, which has the
potential to spuriously enable SVE for userspace.
We probably never saw the issue because no VMM uses SVE, but
that's still pretty bad. Unconditionally clearing the flag
on vcpu load addresses the issue.
Fixes: 8383741ab2e7 ("KVM: arm64: Get rid of host SVE tracking/saving")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220528113829.1043361-2-maz@kernel.org
---
arch/arm64/kvm/fpsimd.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index 3d251a4d2cf7..8267ff4642d3 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -80,6 +80,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
vcpu->arch.flags &= ~KVM_ARM64_FP_ENABLED;
vcpu->arch.flags |= KVM_ARM64_FP_HOST;
+ vcpu->arch.flags &= ~KVM_ARM64_HOST_SVE_ENABLED;
if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)
vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;
--
2.34.1
next prev parent reply other threads:[~2022-06-10 9:30 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-10 9:28 [PATCH v2 00/19] KVM/arm64: Refactoring the vcpu flags Marc Zyngier
2022-06-10 9:28 ` Marc Zyngier [this message]
2022-06-10 9:28 ` [PATCH v2 02/19] KVM: arm64: Always start with clearing SME flag on load Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 03/19] KVM: arm64: Drop FP_FOREIGN_STATE from the hypervisor code Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 04/19] KVM: arm64: Move FP state ownership from flag to a tristate Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 05/19] KVM: arm64: Add helpers to manipulate vcpu flags among a set Marc Zyngier
2022-06-10 13:05 ` Fuad Tabba
2022-06-11 18:37 ` Reiji Watanabe
2022-06-12 8:59 ` Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 06/19] KVM: arm64: Add three sets of flags to the vcpu state Marc Zyngier
2022-06-11 18:41 ` Reiji Watanabe
2022-06-10 9:28 ` [PATCH v2 07/19] KVM: arm64: Move vcpu configuration flags into their own set Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 08/19] KVM: arm64: Move vcpu PC/Exception flags to the input flag set Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 09/19] KVM: arm64: Move vcpu debug/SPE/TRBE " Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 10/19] KVM: arm64: Move vcpu SVE/SME flags to the state " Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 11/19] KVM: arm64: Move vcpu ON_UNSUPPORTED_CPU flag " Marc Zyngier
2022-06-15 13:14 ` Alexandru Elisei
2022-06-15 13:23 ` Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 12/19] KVM: arm64: Move vcpu WFIT " Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 13/19] KVM: arm64: Kill unused vcpu flags field Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 14/19] KVM: arm64: Convert vcpu sysregs_loaded_on_cpu to a state flag Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 15/19] KVM: arm64: Warn when PENDING_EXCEPTION and INCREMENT_PC are set together Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 16/19] KVM: arm64: Add build-time sanity checks for flags Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 17/19] KVM: arm64: Reduce the size of the vcpu flag members Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 18/19] KVM: arm64: Document why pause cannot be turned into a flag Marc Zyngier
2022-06-10 9:28 ` [PATCH v2 19/19] KVM: arm64: Move the handling of !FP outside of the fast path Marc Zyngier
2022-06-14 4:15 ` Reiji Watanabe
2022-06-29 9:58 ` [PATCH v2 00/19] KVM/arm64: Refactoring the vcpu flags Marc Zyngier
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