On Wed, Apr 28, 2021 at 12:46 PM Ricardo Koller <ricarkol@xxxxxxxxxx> wrote: > > On Thu, Apr 22, 2021 at 09:02:09AM +0200, Paolo Bonzini wrote: > > On 22/04/21 02:56, Ricardo Koller wrote: > > > The kernel has a set of utilities and definitions to deal with x86 cpu > > > features. The x86 KVM selftests don't use them, and instead have > > > evolved to use differing and ad-hoc methods for checking features. The > > > advantage of the kernel feature definitions is that they use a format > > > that embeds the info needed to extract them from cpuid (function, index, > > > and register to use). > > > > > > The first 3 patches massage the related cpuid header files in the kernel > > > side, then copy them into tools/ so they can be included by selftests. > > > The last 2 patches replace the tests checking for cpu features to use > > > the definitions and utilities introduced from the kernel. > > > > I queued the first, but I am not sure about the rest. > > > > An alternative is to copy over the code from kvm-unit-tests which encodes > > the leaf/subleaf/register/bit values into the X86_FEATURE_* value. Sharing > > code with kvm-unit-tests is probably simpler than adding #ifdef __KERNEL__ > > and keeping the headers in sync. > > > > Paolo > > > > Thanks. I was thinking about kvm-unit-tests, but the issue is that it > would also be a copy. And just like with kernel headers, it would be > ideal to keep them in-sync. The advantage of the kernel headers is that > it's much easier to check and fix diffs with them. On the other hand, as > you say, there would not be any #ifdef stuff with kvm=unit-tests. Please > let me know what you think. I think the kvm-unit-tests implementation is superior to the kernel implementation, but that's probably because I suggested it. Still, I think there's an argument to be made that selftests, unlike kvm-unit-tests, are part of the kernel distribution and should be consistent with the kernel where possible. Paolo?
