[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 1/2] x86/hvm: allow guest to use clflushopt and clwb
On 07/01/16 13:49, Jan Beulich wrote: >>>> On 30.12.15 at 12:48, <haozhong.zhang@xxxxxxxxx> wrote: >> --- a/xen/arch/x86/hvm/hvm.c >> +++ b/xen/arch/x86/hvm/hvm.c >> @@ -4583,21 +4583,30 @@ void hvm_cpuid(unsigned int input, unsigned int >> *eax, unsigned int *ebx, >> *edx &= ~cpufeat_mask(X86_FEATURE_PSE36); >> break; >> case 0x7: >> - if ( (count == 0) && !cpu_has_smep ) >> - *ebx &= ~cpufeat_mask(X86_FEATURE_SMEP); >> + if ( count == 0 ) >> + { >> + if ( !cpu_has_smep ) >> + *ebx &= ~cpufeat_mask(X86_FEATURE_SMEP); >> + >> + if ( !cpu_has_smap ) >> + *ebx &= ~cpufeat_mask(X86_FEATURE_SMAP); >> + >> + /* Don't expose MPX to hvm when VMX support is not available */ >> + if ( !(vmx_vmexit_control & VM_EXIT_CLEAR_BNDCFGS) || >> + !(vmx_vmentry_control & VM_ENTRY_LOAD_BNDCFGS) ) >> + *ebx &= ~cpufeat_mask(X86_FEATURE_MPX); >> >> - if ( (count == 0) && !cpu_has_smap ) >> - *ebx &= ~cpufeat_mask(X86_FEATURE_SMAP); >> + /* Don't expose INVPCID to non-hap hvm. */ >> + if ( !hap_enabled(d) ) >> + *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID); >> >> - /* Don't expose MPX to hvm when VMX support is not available */ >> - if ( (count == 0) && >> - (!(vmx_vmexit_control & VM_EXIT_CLEAR_BNDCFGS) || >> - !(vmx_vmentry_control & VM_ENTRY_LOAD_BNDCFGS)) ) >> - *ebx &= ~cpufeat_mask(X86_FEATURE_MPX); >> + if ( !cpu_has_clflushopt ) >> + *ebx &= ~cpufeat_mask(X86_FEATURE_CLFLUSHOPT); >> + >> + if ( !cpu_has_clwb ) >> + *ebx &= ~cpufeat_mask(X86_FEATURE_CLWB); > I don't think we need this: Other than other things adjusted here, > there's nothing disabling these two features when found available, > and there are no extra conditions to consider. Otherwise, if we > were to follow this route, quite a bit of code would need to be > added to other case statements in this function. But that's all (I > think) going to be taken care of by Andrew's CPUID leveling series. My series does take care of all of this. I would prefer that these two changes get taken as soon as they are ready, so I can rebase. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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