On Thu, Nov 10, 2016 at 09:50:24AM -0500, Boris Ostrovsky wrote: > Currently hypervisor provides PV guest's CPUID(1).EBX[31:24] (initial > APIC ID) with contents of that field on the processor that launched > the guest. This results in the guest reporting different initial > APIC IDs across runs. > > We should be consistent in how this value is reported, let's set > it to 0 (which is also what Linux guests expect). > > Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
I will defer this to x86 maintainers. > --- > > I think this should go to stable branches as well. This has been causing > problems lately in Linux with introduction of topology maps. > > > tools/libxc/xc_cpuid_x86.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c > index d761805..1f26294 100644 > --- a/tools/libxc/xc_cpuid_x86.c > +++ b/tools/libxc/xc_cpuid_x86.c > @@ -618,6 +618,12 @@ static void xc_cpuid_pv_policy(xc_interface *xch, > /* Host topology exposed to PV guest. Provide host value. */ > bool host_htt = regs[3] & bitmaskof(X86_FEATURE_HTT); > > + /* > + * Don't pick host's Initial APIC ID which can change from run > + * to run. > + */ > + regs[1] &= 0x00ffffffu; > + > regs[2] = info->featureset[featureword_of(X86_FEATURE_SSE3)]; > regs[3] = (info->featureset[featureword_of(X86_FEATURE_FPU)] & > ~bitmaskof(X86_FEATURE_HTT)); > -- > 2.7.4 > _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
