On 14.09.2023 08:03, Juergen Gross wrote: > On 14.09.23 06:47, Xin Li wrote: >> From: "H. Peter Anvin (Intel)" <hpa@xxxxxxxxx> >> >> Any FRED CPU will always have the following features as its baseline: >> 1) LKGS, load attributes of the GS segment but the base address into >> the IA32_KERNEL_GS_BASE MSR instead of the GS segment’s descriptor >> cache. >> 2) WRMSRNS, non-serializing WRMSR for faster MSR writes. >> >> Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> >> Tested-by: Shan Kang <shan.kang@xxxxxxxxx> >> Signed-off-by: Xin Li <xin3.li@xxxxxxxxx> > > In order to avoid having to add paravirt support for FRED I think > xen_init_capabilities() should gain: > > + setup_clear_cpu_cap(X86_FEATURE_FRED); I don't view it as very likely that Xen would expose FRED to PV guests (Andrew?), at which point such a precaution may not be necessary. Jan
