linux-kernel - [PATCH 4/4] KVM: arm64: trap guest access for REVIDR_EL1 and AIDR

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Message-ID: <20250210154953.27002-5-sebott@redhat.com>
Date: Mon, 10 Feb 2025 16:49:53 +0100
From: Sebastian Ott <sebott@...hat.com>
To: 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>,
	Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
Cc: Cornelia Huck <cohuck@...hat.com>,
	Eric Auger <eric.auger@...hat.com>,
	linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH 4/4] KVM: arm64: trap guest access for REVIDR_EL1 and AIDR_EL1

Setup a trap for guest access of REVIDR_EL1 and AIDR_EL1 when
the VMs value differs from hardware.

Signed-off-by: Sebastian Ott <sebott@...hat.com>
---
 arch/arm64/kvm/sys_regs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 7d588fedb50a..2918872e3d2a 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -4910,6 +4910,10 @@ static void vcpu_set_hcr(struct kvm_vcpu *vcpu)
 	else
 		vcpu->arch.hcr_el2 |= HCR_TID2;
 
+	if ((kvm_read_vm_id_reg(kvm, SYS_REVIDR_EL1) != read_sysreg(REVIDR_EL1)) ||
+	    (kvm_read_vm_id_reg(kvm, SYS_AIDR_EL1) != read_sysreg(AIDR_EL1)))
+		vcpu->arch.hcr_el2 |= HCR_TID1;
+
 	if (vcpu_el1_is_32bit(vcpu))
 		vcpu->arch.hcr_el2 &= ~HCR_RW;
 
-- 
2.42.0