On 8/11/21 11:13 AM, Sean Christopherson wrote: > On Wed, Aug 11, 2021, Babu Moger wrote: >> >> On 8/11/21 2:09 AM, Paolo Bonzini wrote: >>> On 11/08/21 01:38, Babu Moger wrote: >>>> No. This will not work. The PKU feature flag is bit 30. That is 2^30 >>>> iterations to cover the tests for this feature. Looks like I need to split >>>> the tests into PKU and non PKU tests. For PKU tests I may need to change >>>> the bump frequency (in ac_test_bump_one) to much higher value. Right now, >>>> it is 1. Let me try that, >>> >>> The simplest way to cut on tests, which is actually similar to this patch, >>> would be: >>> >>> - do not try all combinations of PTE access bits when reserved bits are set >>> >>> - do not try combinations with more than one reserved bit set >> >> Did you mean this? Just doing this reduces the combination by huge number. >> I don't need to add your first PTE access combinations. >> >> diff --git a/x86/access.c b/x86/access.c >> index 47807cc..a730b6b 100644 >> --- a/x86/access.c >> +++ b/x86/access.c >> @@ -317,9 +317,7 @@ static _Bool ac_test_legal(ac_test_t *at) >> /* >> * Shorten the test by avoiding testing too many reserved bit >> combinations >> */ >> - if ((F(AC_PDE_BIT51) + F(AC_PDE_BIT36) + F(AC_PDE_BIT13)) > 1) >> - return false; >> - if ((F(AC_PTE_BIT51) + F(AC_PTE_BIT36)) > 1) >> + if ((F(AC_PDE_BIT51) + F(AC_PDE_BIT36) + F(AC_PDE_BIT13) + >> F(AC_PTE_BIT51) + F(AC_PTE_BIT36)) > 1) >> return false; >> >> return true; > > Looks good to me, is it sufficient to keep the overall runtime sane?. And maybe It keeps the running time about 2 minutes. > update the comment too, e.g. something like > > /* > * Skip testing multiple reserved bits to shorten the test. Reserved > * bit page faults are terminal and multiple reserved bits do not affect > * the error code; the odds of a KVM bug are super low, and the odds of > * actually being able to detect a bug are even lower. > */ > Sure. Will update the commit log. Thanks Babu
