From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Cc: James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oliver.upton@linux.dev>,
Zenghui Yu <yuzenghui@huawei.com>, Will Deacon <will@kernel.org>
Subject: [PATCH v2 5/5] KVM: arm64: vhe: Drop extra isb() on guest exit
Date: Sat, 8 Apr 2023 17:04:27 +0100 [thread overview]
Message-ID: <20230408160427.10672-6-maz@kernel.org> (raw)
In-Reply-To: <20230408160427.10672-1-maz@kernel.org>
__kvm_vcpu_run_vhe() end on VHE with an isb(). However, this
function is only reachable via kvm_call_hyp_ret(), which already
contains an isb() in order to mimick the behaviour of nVHE and
provide a context synchronisation event.
We thus have two isb()s back to back, which is one too many.
Drop the first one and solely rely on the one in the helper.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/hyp/vhe/switch.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index cd3f3117bf16..3d868e84c7a0 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -227,11 +227,10 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
/*
* When we exit from the guest we change a number of CPU configuration
- * parameters, such as traps. Make sure these changes take effect
- * before running the host or additional guests.
+ * parameters, such as traps. We rely on the isb() in kvm_call_hyp*()
+ * to make sure these changes take effect before running the host or
+ * additional guests.
*/
- isb();
-
return ret;
}
--
2.34.1
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next prev parent reply other threads:[~2023-04-08 16:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-08 16:04 [PATCH v2 0/5] KVM: arm64: Synchronise speculative page table walks on translation regime change Marc Zyngier
2023-04-08 16:04 ` [PATCH v2 1/5] KVM: arm64: nvhe: Synchronise with page table walker on vcpu run Marc Zyngier
2023-04-13 0:10 ` Oliver Upton
2023-04-08 16:04 ` [PATCH v2 2/5] KVM: arm64: nvhe: Synchronise with page table walker on TLBI Marc Zyngier
2023-04-13 0:09 ` Oliver Upton
2023-04-13 7:37 ` Marc Zyngier
2023-04-08 16:04 ` [PATCH v2 3/5] KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc() Marc Zyngier
2023-04-13 0:10 ` Oliver Upton
2023-04-08 16:04 ` [PATCH v2 4/5] KVM: arm64: vhe: Synchronise with page table walker on MMU update Marc Zyngier
2023-04-13 0:11 ` Oliver Upton
2023-04-08 16:04 ` Marc Zyngier [this message]
2023-04-13 0:15 ` [PATCH v2 5/5] KVM: arm64: vhe: Drop extra isb() on guest exit Oliver Upton
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