Re: [Xen-devel] [PATCH v2 06/12] x86/vmx: expose LMCE feature via guest MSR_IA32_FEATURE_CONTROL

[Jan Beulich]

>>> On 17.03.17 at 07:46,  wrote:
> --- a/xen/arch/x86/cpu/mcheck/mce_intel.c
> +++ b/xen/arch/x86/cpu/mcheck/mce_intel.c
> @@ -955,3 +955,7 @@ int vmce_intel_rdmsr(const struct vcpu *v, uint32_t msr, 
> uint64_t *val)
>  return 1;
>  }
>  
> +bool vmce_support_lmce(const struct vcpu *v)

I think you mean vmce_supports_lmce() (or vmce_has_lmce()). I'm
sorry for having overlooked this in v1.

>  static int vmx_msr_read_intercept(unsigned int msr, uint64_t *msr_content)
>  {
> +struct vcpu *curr = current;

const

Jan


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[Xen-devel] [PATCH v2 06/12] x86/vmx: expose LMCE feature via guest MSR_IA32_FEATURE_CONTROL

[Haozhong Zhang]

If MCG_LMCE_P is present in guest MSR_IA32_MCG_CAP, then set LMCE and
LOCK bits in guest MSR_IA32_FEATURE_CONTROL. Intel SDM requires those
bits are set before SW can enable LMCE.

Signed-off-by: Haozhong Zhang 
---
Cc: Jan Beulich 
Cc: Andrew Cooper 
Cc: Jun Nakajima 
Cc: Kevin Tian 

Changes in v2:
 * Remove unnecessary !! in vmce_support_lmce().
 * Rename "struct vcpu *v" to "struct vcpu *curr" in vmx_msr_read_intercept().
 * Remove the duplicated neseted VMX check in vmx_msr_read_intercept().
---
 xen/arch/x86/cpu/mcheck/mce_intel.c | 4 
 xen/arch/x86/hvm/vmx/vmx.c  | 9 +
 xen/arch/x86/hvm/vmx/vvmx.c | 4 
 xen/include/asm-x86/mce.h   | 1 +
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/cpu/mcheck/mce_intel.c 
b/xen/arch/x86/cpu/mcheck/mce_intel.c
index f8cf5e6..bf0e8ff 100644
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c
@@ -955,3 +955,7 @@ int vmce_intel_rdmsr(const struct vcpu *v, uint32_t msr, 
uint64_t *val)
 return 1;
 }
 
+bool vmce_support_lmce(const struct vcpu *v)
+{
+return v->arch.vmce.mcg_cap & MCG_LMCE_P;
+}
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 894d7d4..301fda0 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -55,6 +55,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 
@@ -2753,6 +2754,8 @@ static int is_last_branch_msr(u32 ecx)
 
 static int vmx_msr_read_intercept(unsigned int msr, uint64_t *msr_content)
 {
+struct vcpu *curr = current;
+
 HVM_DBG_LOG(DBG_LEVEL_MSR, "ecx=%#x", msr);
 
 switch ( msr )
@@ -2770,6 +2773,12 @@ static int vmx_msr_read_intercept(unsigned int msr, 
uint64_t *msr_content)
 __vmread(GUEST_IA32_DEBUGCTL, msr_content);
 break;
 case MSR_IA32_FEATURE_CONTROL:
+*msr_content = IA32_FEATURE_CONTROL_LOCK;
+if ( vmce_support_lmce(curr) )
+*msr_content |= IA32_FEATURE_CONTROL_LMCE_ON;
+if ( nestedhvm_enabled(curr->domain) )
+*msr_content |= IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX;
+break;
 case MSR_IA32_VMX_BASIC...MSR_IA32_VMX_VMFUNC:
 if ( !nvmx_msr_read_intercept(msr, msr_content) )
 goto gp_fault;
diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index e2c0951..4aa70ef 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -2068,10 +2068,6 @@ int nvmx_msr_read_intercept(unsigned int msr, u64 
*msr_content)
 data = gen_vmx_msr(data, VMX_ENTRY_CTLS_DEFAULT1, host_data);
 break;
 
-case MSR_IA32_FEATURE_CONTROL:
-data = IA32_FEATURE_CONTROL_LOCK |
-   IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX;
-break;
 case MSR_IA32_VMX_VMCS_ENUM:
 /* The max index of VVMCS encoding is 0x1f. */
 data = 0x1f << 1;
diff --git a/xen/include/asm-x86/mce.h b/xen/include/asm-x86/mce.h
index 549bef3..6b827ef 100644
--- a/xen/include/asm-x86/mce.h
+++ b/xen/include/asm-x86/mce.h
@@ -36,6 +36,7 @@ extern void vmce_init_vcpu(struct vcpu *);
 extern int vmce_restore_vcpu(struct vcpu *, const struct hvm_vmce_vcpu *);
 extern int vmce_wrmsr(uint32_t msr, uint64_t val);
 extern int vmce_rdmsr(uint32_t msr, uint64_t *val);
+extern bool vmce_support_lmce(const struct vcpu *v);
 
 extern unsigned int nr_mce_banks;
 
-- 
2.10.1


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