[PATCH v4 15/21] kvm: x86: Add XCR0 support for Intel AMX
From: Yang Zhong <hidden>
Date: 2021-12-29 13:15:07
Also in:
kvm, linux-kselftest, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Jing Liu <redacted> Two XCR0 bits are defined for AMX to support XSAVE mechanism. Bit 17 is for tilecfg and bit 18 is for tiledata. The value of XCR0[17:18] is always either 00b or 11b. Also, SDM recommends that only 64-bit operating systems enable Intel AMX by setting XCR0[18:17]. 32-bit host kernel never sets the tile bits in vcpu->arch.guest_supported_xcr0. Signed-off-by: Jing Liu <redacted> Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Yang Zhong <redacted> --- arch/x86/kvm/x86.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a48a89f73027..bdf89c28d2ce 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c@@ -210,7 +210,7 @@ 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);
@@ -990,6 +990,11 @@ 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) && + ((xcr0 & XFEATURE_MASK_XTILE) != XFEATURE_MASK_XTILE)) + return 1; + vcpu->arch.xcr0 = xcr0; if ((xcr0 ^ old_xcr0) & XFEATURE_MASK_EXTEND)