[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 2/2] x86/hvm: add support for pcommit instruction
On 01/07/16 06:53, 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 > > @@ -4605,6 +4605,9 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, > > unsigned int *ebx, > > > > if ( !cpu_has_clwb ) > > *ebx &= ~cpufeat_mask(X86_FEATURE_CLWB); > > + > > + if ( !cpu_has_pcommit ) > > + *ebx &= ~cpufeat_mask(X86_FEATURE_PCOMMIT); > > Other than for patch 1, this not only need to stay, but needs to be > extended along the lines of X86_FEATURE_MPX handling. > In section "PCOMMIT - Virtualization Support" of Intel Architecture Instruction Set Extensions Programming Reference, it says IA32_VMX_PROCBASED_CTLS2[53] (which enumerates support for the 1-setting of âPCOMMIT exitingâ) is always the same as CPUID.07H:EBX.PCOMMIT[bit 22]. so checking cpu_has_pcommit is enough here. > > @@ -1075,6 +1076,9 @@ static int construct_vmcs(struct vcpu *v) > > __vmwrite(PLE_WINDOW, ple_window); > > } > > > > + if ( cpu_has_vmx_pcommit ) > > + v->arch.hvm_vmx.secondary_exec_control &= ~SECONDARY_EXEC_PCOMMIT; > > Why is this conditional? Instead of the if() there should be a comment > imo. > The condition is not necessary. I'll remove it and add a comment in the next version. Haozhong _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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