linux-kernel - [PATCH v1 1/2] KVM: arm64: nv: fix S2 translation for nVHE guests

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Message-ID: <20250806141707.3479194-2-volodymyr_babchuk@epam.com>
Date: Wed, 6 Aug 2025 14:17:55 +0000
From: Volodymyr Babchuk <Volodymyr_Babchuk@...m.com>
To: "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "kvmarm@...ts.linux.dev"
	<kvmarm@...ts.linux.dev>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@...m.com>, Marc Zyngier
	<maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, Joey Gouly
	<joey.gouly@....com>, Suzuki K Poulose <suzuki.poulose@....com>, Zenghui Yu
	<yuzenghui@...wei.com>, Catalin Marinas <catalin.marinas@....com>, Will
 Deacon <will@...nel.org>
Subject: [PATCH v1 1/2] KVM: arm64: nv: fix S2 translation for nVHE guests

According to ARM architecture specification (ARM DDI 0487 L.a, section
C5.4.3), Stage 2 translation should be skipped when VHE is active, or,
in other words, E2H bit is set. Fix the code by inverting both check
and comment.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@...m.com>
---
 arch/arm64/kvm/at.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index a25be111cd8f8..5e7c3fb01273c 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -1412,10 +1412,10 @@ void __kvm_at_s12(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
 		return;
 
 	/*
-	 * If we only have a single stage of translation (E2H=0 or
+	 * If we only have a single stage of translation (E2H=1 or
 	 * TGE=1), exit early. Same thing if {VM,DC}=={0,0}.
 	 */
-	if (!vcpu_el2_e2h_is_set(vcpu) || vcpu_el2_tge_is_set(vcpu) ||
+	if (vcpu_el2_e2h_is_set(vcpu) || vcpu_el2_tge_is_set(vcpu) ||
 	    !(vcpu_read_sys_reg(vcpu, HCR_EL2) & (HCR_VM | HCR_DC)))
 		return;
 
-- 
2.50.1