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

Mark Brown posted 6 patches 1 month, 2 weeks ago
There is a newer version of this series
[PATCH v15 5/6] KVM: arm64: Allow GCS to be enabled for guests
Posted by Mark Brown 1 month, 2 weeks ago
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@kernel.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
Re: [PATCH v15 5/6] KVM: arm64: Allow GCS to be enabled for guests
Posted by Marc Zyngier 1 month, 2 weeks ago
On Wed, 20 Aug 2025 15:14:45 +0100,
Mark Brown <broonie@kernel.org> wrote:
> 
> 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@kernel.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);
> 

Still disabled for NV in limit_nv_id_reg().

	M.

-- 
Jazz isn't dead. It just smells funny.