arm64: support Armv8.8 memcpy instructions in userspace

[PATCH 06/10] KVM: arm64: hide MOPS from guests

Posted by Kristina Martsenko 2 years, 6 months ago

As FEAT_MOPS is not supported in guests yet, hide it from the ID
registers for guests.

The MOPS instructions are UNDEFINED in guests as HCRX_EL2.MSCEn is not
set in HCRX_GUEST_FLAGS, and will take an exception to EL1 if executed.

Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
---
 arch/arm64/kvm/sys_regs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0bc7df55916e..3456205c6b92 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1213,6 +1213,7 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r
 				 ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_GPA3));
 		if (!cpus_have_final_cap(ARM64_HAS_WFXT))
 			val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
+		val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_MOPS);
 		break;
 	case SYS_ID_AA64DFR0_EL1:
 		/* Limit debug to ARMv8.0 */
-- 
2.25.1

Re: [PATCH 06/10] KVM: arm64: hide MOPS from guests

Posted by Catalin Marinas 2 years, 5 months ago

On Thu, Feb 16, 2023 at 04:00:08PM +0000, Kristina Martsenko wrote:
> As FEAT_MOPS is not supported in guests yet, hide it from the ID
> registers for guests.
> 
> The MOPS instructions are UNDEFINED in guests as HCRX_EL2.MSCEn is not
> set in HCRX_GUEST_FLAGS, and will take an exception to EL1 if executed.
> 
> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>