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Re: [Qemu-devel] [PATCH v5 2/3] x86: Data structure changes to support M
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH v5 2/3] x86: Data structure changes to support MSR based features |
Date: |
Thu, 25 Oct 2018 10:36:37 -0300 |
User-agent: |
Mutt/1.9.2 (2017-12-15) |
On Thu, Oct 25, 2018 at 11:06:59AM +0800, Robert Hoo wrote:
> On Wed, 2018-10-24 at 07:16 -0300, Eduardo Habkost wrote:
[...]
> > > + struct { /*CPUID that enumerate this MSR*/
> > > + FeatureWord cpuid_class;
> > > + uint32_t cpuid_flag;
> > > + } cpuid_dep;
> >
> > Aren't you going to use this field anywhere? Probably we want to
> > prevent the VM from starting if a bit is set in the feature world
> > but the cpuid_dep bit is not set.
> >
> > e.g.:
> > qemu-system-x86_64 -cpu Skylake-Client,-arch-capabilities,+rsba
> > probably should fail to start.
>
> How about in x86_cpu_filter_features() filters the MSR feature word, if
> its dependent CPUID feature bit is not set?
> The filter results will be record in cpu->filtered_features, and print
> out, like other filtered features.
Sounds good to me.
--
Eduardo