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From: Marc Zyngier <maz@kernel.org>
To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
	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>,
	Fuad Tabba <tabba@google.com>,
	kernel-team@android.com
Subject: [PATCH] KVM: arm64: Fix reporting of endianess when the access originates at EL0
Date: Tue, 12 Oct 2021 12:23:12 +0100	[thread overview]
Message-ID: <20211012112312.1247467-1-maz@kernel.org> (raw)

We currently check SCTLR_EL1.EE when computing the address of
a faulting guest access. However, the fault could have occured at
EL0, in which case the right bit to check would be SCTLR_EL1.E0E.

This is pretty unlikely to cause any issue in practice: You'd have
to have a guest with a LE EL1 and a BE EL0 (or the other way around),
and have mapped a device into the EL0 page tables.

Good luck with that!

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_emulate.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 1fadb5d98a36..14ee8319b1ce 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -396,7 +396,10 @@ static inline bool kvm_vcpu_is_be(struct kvm_vcpu *vcpu)
 	if (vcpu_mode_is_32bit(vcpu))
 		return !!(*vcpu_cpsr(vcpu) & PSR_AA32_E_BIT);
 
-	return !!(vcpu_read_sys_reg(vcpu, SCTLR_EL1) & (1 << 25));
+	if (vcpu_mode_priv(vcpu))
+		return !!(vcpu_read_sys_reg(vcpu, SCTLR_EL1) & SCTLR_ELx_EE);
+	else
+		return !!(vcpu_read_sys_reg(vcpu, SCTLR_EL1) & SCTLR_EL1_E0E);
 }
 
 static inline unsigned long vcpu_data_guest_to_host(struct kvm_vcpu *vcpu,
-- 
2.30.2


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             reply	other threads:[~2021-10-12 11:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-12 11:23 Marc Zyngier [this message]
2021-10-12 12:00 ` [PATCH] KVM: arm64: Fix reporting of endianess when the access originates at EL0 Andrew Jones
2021-10-12 14:20   ` Marc Zyngier
2021-10-17 10:20 ` Marc Zyngier

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