linux-kernel - [PATCH v8 6/6] KVM: x86: Expose LAM feature to userspace VMM

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Message-Id: <20230510060611.12950-7-binbin.wu@linux.intel.com>
Date:   Wed, 10 May 2023 14:06:11 +0800
From:   Binbin Wu <binbin.wu@...ux.intel.com>
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com, chao.gao@...el.com,
        kai.huang@...el.com, robert.hu@...ux.intel.com,
        binbin.wu@...ux.intel.com
Subject: [PATCH v8 6/6] KVM: x86: Expose LAM feature to userspace VMM

From: Robert Hoo <robert.hu@...ux.intel.com>

LAM feature is enumerated by CPUID.7.1:EAX.LAM[bit 26].
Expose the feature to userspace as the final step after the following
supports:
- CR4.LAM_SUP virtualization
- CR3.LAM_U48 and CR3.LAM_U57 virtualization
- Check and untag 64-bit linear address when LAM applies in instruction
  emulations and VMExit handlers.

Signed-off-by: Robert Hoo <robert.hu@...ux.intel.com>
Signed-off-by: Binbin Wu <binbin.wu@...ux.intel.com>
Reviewed-by: Jingqi Liu <jingqi.liu@...el.com>
Reviewed-by: Chao Gao <chao.gao@...el.com>
Tested-by: Xuelian Guo <xuelian.guo@...el.com>
---
 arch/x86/kvm/cpuid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 123bf8b97a4b..fc8286f747ac 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -664,7 +664,7 @@ void kvm_set_cpu_caps(void)
 	kvm_cpu_cap_mask(CPUID_7_1_EAX,
 		F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) |
 		F(FZRM) | F(FSRS) | F(FSRC) |
-		F(AMX_FP16) | F(AVX_IFMA)
+		F(AMX_FP16) | F(AVX_IFMA) | F(LAM)
 	);
 
 	kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
-- 
2.25.1