On Tue, Feb 18, 2025, Maxim Levitsky wrote:
> On Wed, 2024-10-02 at 19:56 -0400, Maxim Levitsky wrote:
> > While this is not likely, it is valid for the MSR_LBR_TOS
> > to contain 0 value, after a test which issues a series of branches, if the
> > number of branches recorded was divisible by the number of LBR msrs.
> >
> > This unfortunately depends on the compiler, the number of LBR registers,
> > and it is not even deterministic between different runs of the test,
> > because interrupts, rescheduling, and various other events can affect total
> > number of branches done.
> >
> > Therefore drop the check, instead of trying to fix it.
> >
> > Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
> > ---
> > x86/pmu_lbr.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/x86/pmu_lbr.c b/x86/pmu_lbr.c
> > index c6f010847..8ca8ed044 100644
> > --- a/x86/pmu_lbr.c
> > +++ b/x86/pmu_lbr.c
> > @@ -98,7 +98,6 @@ int main(int ac, char **av)
> > lbr_test();
> > wrmsr(MSR_IA32_DEBUGCTLMSR, 0);
> >
> > - report(rdmsr(MSR_LBR_TOS) != 0, "The guest LBR MSR_LBR_TOS value is good.");
> > for (i = 0; i < max; ++i) {
> > if (!rdmsr(lbr_to + i) || !rdmsr(lbr_from + i))
> > break;
>
> Hi,
>
> This is the other kvm-unit-tests patch that I have a ticket open for,
> and I would like to get this merged and close the ticket.
I'll grab it. I'm hoping to get the pull request put together tomorrow, but I
might not get to it until Thusrday.
