On Sat, 2016-10-29 at 08:21 -0400, Paolo Bonzini wrote: > > Currently none of the bits in CPUID[7,0].edx is ever masked by the > host, so > this would be enough. If we ever need to do some masking, I guess > I'll > practice my puss-in-boots look and submit a patch to add CPUID[7,0] > back > as a separate cpufeature entr.
I think that in v4.9-rc2 the CPUID[7,0].edx bits can be masked out by applying noxsave to cmdline. Using directly cpu_count will result in passing the bits in edx to a guest directly while the xsaveopt and rest of AVX512 features bits will be cleared. Thx Piotr
