* [PATCH v2] x86/vmx: correct the SMEP logic for HVM_CR0_GUEST_RESERVED_BITS
@ 2014-04-28 2:44 Feng Wu
2014-04-28 8:50 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Feng Wu @ 2014-04-28 2:44 UTC (permalink / raw)
To: xen-devel
Cc: kevin.tian, Feng Wu, JBeulich, andrew.cooper3, eddie.dong,
jun.nakajima
When checking the SMEP feature for HVM guests, we should check the
VCPU instead of the host CPU.
Signed-off-by: Feng Wu <feng.wu@intel.com>
---
xen/include/asm-x86/hvm/hvm.h | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index dcc3483..99bfc4c 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -351,6 +351,19 @@ static inline int hvm_event_pending(struct vcpu *v)
return hvm_funcs.event_pending(v);
}
+static inline bool_t hvm_vcpu_has_smep(void)
+{
+ unsigned int eax, ebx;
+
+ hvm_cpuid(0x0, &eax, NULL, NULL, NULL);
+
+ if (eax < 0x7)
+ return 0;
+
+ hvm_cpuid(0x7, NULL, &ebx, NULL, NULL);
+ return !!(ebx & cpufeat_mask(X86_FEATURE_SMEP));
+}
+
/* These reserved bits in lower 32 remain 0 after any load of CR0 */
#define HVM_CR0_GUEST_RESERVED_BITS \
(~((unsigned long) \
@@ -370,7 +383,7 @@ static inline int hvm_event_pending(struct vcpu *v)
X86_CR4_DE | X86_CR4_PSE | X86_CR4_PAE | \
X86_CR4_MCE | X86_CR4_PGE | X86_CR4_PCE | \
X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT | \
- (cpu_has_smep ? X86_CR4_SMEP : 0) | \
+ (hvm_vcpu_has_smep() ? X86_CR4_SMEP : 0) | \
(cpu_has_fsgsbase ? X86_CR4_FSGSBASE : 0) | \
((nestedhvm_enabled((_v)->domain) && cpu_has_vmx)\
? X86_CR4_VMXE : 0) | \
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] x86/vmx: correct the SMEP logic for HVM_CR0_GUEST_RESERVED_BITS
2014-04-28 2:44 [PATCH v2] x86/vmx: correct the SMEP logic for HVM_CR0_GUEST_RESERVED_BITS Feng Wu
@ 2014-04-28 8:50 ` Andrew Cooper
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Cooper @ 2014-04-28 8:50 UTC (permalink / raw)
To: Feng Wu; +Cc: kevin.tian, eddie.dong, jun.nakajima, JBeulich, xen-devel
On 28/04/14 03:44, Feng Wu wrote:
> When checking the SMEP feature for HVM guests, we should check the
> VCPU instead of the host CPU.
>
> Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> xen/include/asm-x86/hvm/hvm.h | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
> index dcc3483..99bfc4c 100644
> --- a/xen/include/asm-x86/hvm/hvm.h
> +++ b/xen/include/asm-x86/hvm/hvm.h
> @@ -351,6 +351,19 @@ static inline int hvm_event_pending(struct vcpu *v)
> return hvm_funcs.event_pending(v);
> }
>
> +static inline bool_t hvm_vcpu_has_smep(void)
> +{
> + unsigned int eax, ebx;
> +
> + hvm_cpuid(0x0, &eax, NULL, NULL, NULL);
> +
> + if (eax < 0x7)
> + return 0;
> +
> + hvm_cpuid(0x7, NULL, &ebx, NULL, NULL);
> + return !!(ebx & cpufeat_mask(X86_FEATURE_SMEP));
> +}
> +
> /* These reserved bits in lower 32 remain 0 after any load of CR0 */
> #define HVM_CR0_GUEST_RESERVED_BITS \
> (~((unsigned long) \
> @@ -370,7 +383,7 @@ static inline int hvm_event_pending(struct vcpu *v)
> X86_CR4_DE | X86_CR4_PSE | X86_CR4_PAE | \
> X86_CR4_MCE | X86_CR4_PGE | X86_CR4_PCE | \
> X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT | \
> - (cpu_has_smep ? X86_CR4_SMEP : 0) | \
> + (hvm_vcpu_has_smep() ? X86_CR4_SMEP : 0) | \
> (cpu_has_fsgsbase ? X86_CR4_FSGSBASE : 0) | \
> ((nestedhvm_enabled((_v)->domain) && cpu_has_vmx)\
> ? X86_CR4_VMXE : 0) | \
^ permalink raw reply [flat|nested] 2+ messages in thread
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