On Tue, Jun 25, 2024, Jim Mattson wrote: > On Mon, Jun 17, 2024 at 11:29 AM Maxim Levitsky <mlevitsk@xxxxxxxxxx> wrote: > > > > On Fri, 2024-06-14 at 07:26 -0700, Sean Christopherson wrote: > > > On Thu, Jun 13, 2024, Maxim Levitsky wrote: > > > > Hi! > > > > > > > > This kvm unit test tests that all reserved bits of the MSR_IA32_FLUSH_CMD #GP, but apparently > > > > on some systems this test fails. > > > > > > > > For example I reproduced this on: > > > > > > > > model name : Intel(R) Xeon(R) CPU E3-1260L v5 @ 2.90GHz > > > > stepping : 3 > > > > microcode : 0xf0 > > > > > > > > > > > > As I see in the 'vmx_vcpu_after_set_cpuid', we passthough this msr to the guest AS IS, > > > > thus the unit test tests the microcode. > > > > > > > > So I suspect that the test actually caught a harmless microcode bug. > > > > > > Yeah, we encountered the same thing and came to the same conclusion. > > > > > > > What do you think we should do to workaround this? Maybe disable this check on > > > > affected cpus or turn it into a warning because MSR_IA32_FLUSH_CMD reserved bits > > > > test doesn't test KVM? > > > > > > Ya, Mingwei posted a patch[*] to force KVM to emulate the faulting accesses, which > > > more or less does exactly that, but preserves a bit of KVM coverage. I'll get a > > > KUT pull request sent to Paolo today, I've got a sizeable number of changes ready. > > > > > > [*] https://lore.kernel.org/all/20240417232906.3057638-3-mizhang@xxxxxxxxxx > > > > > > > This works for me. > > Thanks, > > > > Best regards, > > Maxim Levitsky > > Sean and/or Paolo, > > I'm still waiting for this to show up. :) 13a12056be1e4939dadbd0d2cfb65df400832905 x86: msr: testing MSR_IA32_FLUSH_CMD reserved bits only in KVM emulation 51b87946279cf6e9248ceacf0f27833b6ebeef5e x86: Add FEP support on read/write register instructions /drop mic
