linux-kernel - [PATCH v15 5/6] KVM: arm64: Allow GCS to be enabled for guests

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Message-Id: <20250820-arm64-gcs-v15-5-5e334da18b84@kernel.org>
Date: Wed, 20 Aug 2025 15:14:45 +0100
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>, 
 Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>, 
 Oliver Upton <oliver.upton@...ux.dev>, Joey Gouly <joey.gouly@....com>, 
 Suzuki K Poulose <suzuki.poulose@....com>, Shuah Khan <shuah@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-doc@...r.kernel.org, 
 kvmarm@...ts.linux.dev, linux-kselftest@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH v15 5/6] KVM: arm64: Allow GCS to be enabled for guests

Now that required functionality for GCS is in place expose
ID_AA64PFR1_EL1.GCS, allowing guests to be given the feature.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 arch/arm64/kvm/sys_regs.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 592cb5d6497a..60e234422064 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1616,7 +1616,6 @@ static u64 __kvm_read_sanitised_id_reg(const struct kvm_vcpu *vcpu,
 		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_SME);
 		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_RNDR_trap);
 		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_NMI);
-		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_GCS);
 		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_THE);
 		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTEX);
 		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_PFAR);

-- 
2.39.5