On Fri, Jun 14, 2019 at 06:10:12PM +0200, Borislav Petkov wrote: > On Fri, Jun 14, 2019 at 08:24:58AM -0700, Sean Christopherson wrote: > > On Fri, Jun 14, 2019 at 04:57:34PM +0200, Borislav Petkov wrote: > > > On Fri, Jun 14, 2019 at 07:39:12AM -0700, Sean Christopherson wrote: > > > > KVM can't handle Linux-defined leafs without extra tricks > > > > > > and that's what I'm proposing - an extra trick. > > > > It's not a trick, it's bug suppression. > > > > Try running a kernel built with only patches 1/2 and 2/2 applied, along > > with KVM's assertions removed. It'll probably boot fine since most of the > > affected features are option things, but Linux's feature reporting will be > > all kinds of screwed up. > > > > E.g. this WARN triggers because CPUID_7_EDX is 17, not 18 as expected, > > We can decrement NCAPINTS and word 18 in the header. The BUILD_BUG_ONs > should not fire then too. > > But the easier thing is to not remove any defines in the enum > cpuid_leafs thing so that the capabilities array has the proper size for > after patch 2.
Agreed, Fenghua's proposed CPUID_DUMMY is way easier.
