Re: [PATCH] x86/cpuid: Advertise no-lmsle unilaterally to hvm guests

2021-04-12 Thread Jan Beulich
On 12.04.2021 13:39, Andrew Cooper wrote: > On 12/04/2021 11:48, Jan Beulich wrote: >> On 12.04.2021 12:22, Andrew Cooper wrote: >>> --- a/xen/arch/x86/cpuid.c >>> +++ b/xen/arch/x86/cpuid.c >>> @@ -456,6 +456,12 @@ static void __init calculate_hvm_max_policy(void) >>> __set_bit(X86_FEATURE_X2

Re: [PATCH] x86/cpuid: Advertise no-lmsle unilaterally to hvm guests

2021-04-12 Thread Andrew Cooper
On 12/04/2021 11:48, Jan Beulich wrote: > On 12.04.2021 12:22, Andrew Cooper wrote: >> --- a/xen/arch/x86/cpuid.c >> +++ b/xen/arch/x86/cpuid.c >> @@ -456,6 +456,12 @@ static void __init calculate_hvm_max_policy(void) >> __set_bit(X86_FEATURE_X2APIC, hvm_featureset); >> >> /* >> + *

Re: [PATCH] x86/cpuid: Advertise no-lmsle unilaterally to hvm guests

2021-04-12 Thread Jan Beulich
On 12.04.2021 12:22, Andrew Cooper wrote: > --- a/xen/arch/x86/cpuid.c > +++ b/xen/arch/x86/cpuid.c > @@ -456,6 +456,12 @@ static void __init calculate_hvm_max_policy(void) > __set_bit(X86_FEATURE_X2APIC, hvm_featureset); > > /* > + * We don't support EFER.LMSLE at all. AMD has dro

[PATCH] x86/cpuid: Advertise no-lmsle unilaterally to hvm guests

2021-04-12 Thread Andrew Cooper
While part of the original AMD64 spec, Long Mode Segment Limit Enable was a feature not picked up by Intel, and therefore didn't see much adoption in software. AMD have finally dropped the feature from hardware, and allocated a CPUID bit to indicate its absence. Xen has never supported the featur