lkml.org 
[lkml]   [2022]   [Apr]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v10 10/16] KVM: x86: Add XSAVE Support for Architectural LBR
Date
From: Like Xu <like.xu@linux.intel.com>

On processors supporting XSAVES and XRSTORS, Architectural LBR XSAVE
support is enumerated from CPUID.(EAX=0DH, ECX=1):ECX[bit 15].
The detailed sub-leaf for Arch LBR is enumerated in CPUID.(0DH, 0FH).

XSAVES provides a faster means than RDMSR for guest to read all LBRs.
When guest IA32_XSS[bit 15] is set, the Arch LBR state can be saved using
XSAVES and restored by XRSTORS with the appropriate RFBM.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 4 ++++
arch/x86/kvm/x86.c | 2 +-
2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b29c8e75f902..60d92a459f4c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7427,6 +7427,10 @@ static __init void vmx_set_cpu_caps(void)
kvm_cpu_cap_clear(X86_FEATURE_INVPCID);
if (vmx_pt_mode_is_host_guest())
kvm_cpu_cap_check_and_set(X86_FEATURE_INTEL_PT);
+ if (!cpu_has_vmx_arch_lbr()) {
+ kvm_cpu_cap_clear(X86_FEATURE_ARCH_LBR);
+ supported_xss &= ~XFEATURE_MASK_LBR;
+ }

if (!enable_sgx) {
kvm_cpu_cap_clear(X86_FEATURE_SGX);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 13475563c3f6..e33315662db9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -224,7 +224,7 @@ static struct kvm_user_return_msrs __percpu *user_return_msrs;
| XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
| XFEATURE_MASK_PKRU | XFEATURE_MASK_XTILE)

-#define KVM_SUPPORTED_XSS 0
+#define KVM_SUPPORTED_XSS XFEATURE_MASK_LBR

u64 __read_mostly host_efer;
EXPORT_SYMBOL_GPL(host_efer);
--
2.27.0
\
 
 \ /
  Last update: 2022-04-22 09:57    [W:0.771 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site