linux-kernel - [PATCH RFC 7/7] kvm: x86: AMX XCR0 support for guest

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Date:   Sun,  7 Feb 2021 10:42:56 -0500
From:   Jing Liu <jing2.liu@...ux.intel.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jing2.liu@...el.com
Subject: [PATCH RFC 7/7] kvm: x86: AMX XCR0 support for guest

Two XCR0 bits are defined for AMX to support XSAVE mechanism.
Bit 17 is for tilecfg and bit 18 is for tiledata.

Signed-off-by: Jing Liu <jing2.liu@...ux.intel.com>
---
 arch/x86/kvm/x86.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bfbde877221e..f1c5893dee18 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -189,7 +189,7 @@ static struct kvm_user_return_msrs __percpu *user_return_msrs;
 #define KVM_SUPPORTED_XCR0     (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \
 				| XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
 				| XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
-				| XFEATURE_MASK_PKRU)
+				| XFEATURE_MASK_PKRU | XFEATURE_MASK_XTILE)
 
 u64 __read_mostly host_efer;
 EXPORT_SYMBOL_GPL(host_efer);
@@ -946,6 +946,12 @@ static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 		if ((xcr0 & XFEATURE_MASK_AVX512) != XFEATURE_MASK_AVX512)
 			return 1;
 	}
+
+	if (xcr0 & XFEATURE_MASK_XTILE) {
+		if ((xcr0 & XFEATURE_MASK_XTILE) != XFEATURE_MASK_XTILE)
+			return 1;
+	}
+
 	vcpu->arch.xcr0 = xcr0;
 
 	if ((xcr0 ^ old_xcr0) & XFEATURE_MASK_EXTEND)
-- 
2.18.4