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 3/5] KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc()
Date: Sat, 8 Apr 2023 17:04:25 +0100 [thread overview]
Message-ID: <20230408160427.10672-4-maz@kernel.org> (raw)
In-Reply-To: <20230408160427.10672-1-maz@kernel.org>
We rely on the presence of a DSB at the end of kvm_flush_dcache_to_poc()
that, on top of ensuring completion of the cache clean, also covers
the speculative page table walk started from EL1.
Document this dependency.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 552653fa18be..2e9ec4a2a4a3 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -297,6 +297,13 @@ int __pkvm_prot_finalize(void)
params->vttbr = kvm_get_vttbr(mmu);
params->vtcr = host_mmu.arch.vtcr;
params->hcr_el2 |= HCR_VM;
+
+ /*
+ * The CMO below not only cleans the updated params to the
+ * PoC, but also provides the DSB that ensures ongoing
+ * page-table walks that have started before we trapped to EL2
+ * have completed.
+ */
kvm_flush_dcache_to_poc(params, sizeof(*params));
write_sysreg(params->hcr_el2, hcr_el2);
--
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 ` Marc Zyngier [this message]
2023-04-13 0:10 ` [PATCH v2 3/5] KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc() 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 ` [PATCH v2 5/5] KVM: arm64: vhe: Drop extra isb() on guest exit Marc Zyngier
2023-04-13 0:15 ` Oliver Upton
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