linux-kernel - [PATCH] KVM: x86: Enable Intel AVX-512 for guest

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Date:	Wed, 22 Oct 2014 17:35:24 +0800
From:	Chao Peng <chao.p.peng@...ux.intel.com>
To:	gleb@...nel.org, pbonzini@...hat.com
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, fenghua.yu@...el.com, bp@...e.de,
	qiaowei.ren@...el.com, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org, Chao Peng <chao.p.peng@...ux.intel.com>
Subject: [PATCH] KVM: x86: Enable Intel AVX-512 for guest

Expose Intel AVX-512 feature bits to guest. Also add checks for
xcr0 AVX512 related bits according to spec:
http://download-software.intel.com/sites/default/files/managed/71/2e/319433-017.pdf

Signed-off-by: Chao Peng <chao.p.peng@...ux.intel.com>
---
 arch/x86/include/asm/xsave.h |    1 +
 arch/x86/kvm/cpuid.c         |    3 ++-
 arch/x86/kvm/x86.c           |    6 ++++++
 arch/x86/kvm/x86.h           |    3 ++-
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 7e7a79a..5fa9770 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -16,6 +16,7 @@
 #define XSTATE_Hi16_ZMM		0x80
 
 #define XSTATE_FPSSE	(XSTATE_FP | XSTATE_SSE)
+#define XSTATE_AVX512	(XSTATE_OPMASK | XSTATE_ZMM_Hi256 | XSTATE_Hi16_ZMM)
 /* Bit 63 of XCR0 is reserved for future expansion */
 #define XSTATE_EXTEND_MASK	(~(XSTATE_FPSSE | (1ULL << 63)))
 
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 976e3a5..20d8321 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -317,7 +317,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 	const u32 kvm_supported_word9_x86_features =
 		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
 		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
-		F(ADX) | F(SMAP);
+		F(ADX) | F(SMAP) | F(AVX512F) | F(AVX512PF) | F(AVX512ER) |
+		F(AVX512CD);
 
 	/* all calls to cpuid_count() should be made on the same cpu */
 	get_cpu();
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5430e4b..3d77b88 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -651,6 +651,12 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 	if ((!(xcr0 & XSTATE_BNDREGS)) != (!(xcr0 & XSTATE_BNDCSR)))
 		return 1;
 
+	if (xcr0 & XSTATE_AVX512) {
+		if (!(xcr0 & XSTATE_YMM))
+			return 1;
+		if ((xcr0 & XSTATE_AVX512) != XSTATE_AVX512)
+			return 1;
+	}
 	kvm_put_guest_xcr0(vcpu);
 	vcpu->arch.xcr0 = xcr0;
 
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 7cb9c45..cc1d61a 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -162,7 +162,8 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
 bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data);
 
 #define KVM_SUPPORTED_XCR0     (XSTATE_FP | XSTATE_SSE | XSTATE_YMM \
-				| XSTATE_BNDREGS | XSTATE_BNDCSR)
+				| XSTATE_BNDREGS | XSTATE_BNDCSR \
+				| XSTATE_AVX512)
 extern u64 host_xcr0;
 
 extern u64 kvm_supported_xcr0(void);
-- 
1.7.9.5

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