Re: [Xen-devel] [PATCH v3 07/28] xen/x86: Annotate special features
>>> On 15.03.16 at 16:35, wrote: > Some bits in a featureset are not simple a indication of new functionality, > and require special handling. > > APIC, OSXSAVE and OSPKE are fast-forwards of other pieces of state; > IA32_APIC_BASE.EN, CR4.OSXSAVE and CR4.OSPKE. Xen will take care of filling > these appropriately at runtime. > > FDP_EXCP_ONLY and NO_FPU_SEL are bits indicating reduced functionality in > the > x87 pipeline. The effects of these cannot be hidden from the guest, so the > host values will always be provided. > > HTT and CMP_LEGACY indicate how to interpret other cpuid leaves. In most > cases, the toolstack value will be used (with the expectation that these > flags > will match the other provided topology information). However with cpuid > masking, the host values are presented as masking cannot influence what the > guest sees in the dependent leaves. > > Signed-off-by: Andrew Cooper Acked-by: Jan Beulich ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v3 07/28] xen/x86: Annotate special features
On Tue, Mar 15, 2016 at 03:35:03PM +, Andrew Cooper wrote: > Some bits in a featureset are not simple a indication of new functionality, > and require special handling. > > APIC, OSXSAVE and OSPKE are fast-forwards of other pieces of state; > IA32_APIC_BASE.EN, CR4.OSXSAVE and CR4.OSPKE. Xen will take care of filling > these appropriately at runtime. > > FDP_EXCP_ONLY and NO_FPU_SEL are bits indicating reduced functionality in the > x87 pipeline. The effects of these cannot be hidden from the guest, so the > host values will always be provided. > > HTT and CMP_LEGACY indicate how to interpret other cpuid leaves. In most > cases, the toolstack value will be used (with the expectation that these flags > will match the other provided topology information). However with cpuid > masking, the host values are presented as masking cannot influence what the > guest sees in the dependent leaves. > > Signed-off-by: Andrew Cooper Reviewed-by: Konrad Rzeszutek Wilk ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
