Re: [PATCH 04/10] x86/hvm: pkeys, add pkeys support when setting CR4

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 20/11/15 01:16, Wu, Feng wrote:
>> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
>> index 66917ff..953047f 100644
>> --- a/xen/arch/x86/hvm/hvm.c
>> +++ b/xen/arch/x86/hvm/hvm.c
>> @@ -1911,6 +1911,7 @@ static unsigned long
>> hvm_cr4_guest_reserved_bits(const struct vcpu *v,
>>          leaf1_edx = boot_cpu_data.x86_capability[X86_FEATURE_VME / 32];
>>          leaf1_ecx = boot_cpu_data.x86_capability[X86_FEATURE_PCID / 32];
>>          leaf7_0_ebx = boot_cpu_data.x86_capability[X86_FEATURE_FSGSBASE /
>> 32];
>> +        leaf7_0_ecx = boot_cpu_data.x86_capability[X86_FEATURE_PKU / 32];
> What is the purpose of the above change?

So the hunk below can correctly audit a guests attempt to set CR4.PKE.

~Andrew

>
>>      }
>>
>>      return ~(unsigned long)
>> @@ -1946,7 +1947,9 @@ static unsigned long
>> hvm_cr4_guest_reserved_bits(const struct vcpu *v,
>>               (leaf7_0_ebx & cpufeat_mask(X86_FEATURE_SMEP) ?
>>                X86_CR4_SMEP : 0) |
>>               (leaf7_0_ebx & cpufeat_mask(X86_FEATURE_SMAP) ?
>> -              X86_CR4_SMAP : 0));
>> +              X86_CR4_SMAP : 0) |
>> +             (leaf7_0_ecx & cpufeat_mask(X86_FEATURE_PKU) ?
>> +              X86_CR4_PKE : 0));
>>  }
>>
>>  static int hvm_load_cpu_ctxt(struct domain *d, hvm_domain_context_t *h)