| Message ID | 20221021205105.1621014-1-aaronlewis@google.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce and test masked events | expand |
On Fri, Oct 21, 2022, Aaron Lewis wrote: > This series introduces the concept of masked events to the pmu event > filter. Masked events can help reduce the number of events needed in the > pmu event filter by allowing a more generalized matching method to be > used for the unit mask when filtering guest events in the pmu. With > masked events, if an event select should be restricted from the guest, > instead of having to add an entry to the pmu event filter for each > event select + unit mask pair, a masked event can be added to generalize > the unit mask values. ... > Aaron Lewis (7): > kvm: x86/pmu: Correct the mask used in a pmu event filter lookup > kvm: x86/pmu: Remove impossible events from the pmu event filter > kvm: x86/pmu: prepare the pmu event filter for masked events > kvm: x86/pmu: Introduce masked events to the pmu event filter > selftests: kvm/x86: Add flags when creating a pmu event filter > selftests: kvm/x86: Add testing for KVM_SET_PMU_EVENT_FILTER > selftests: kvm/x86: Test masked events One comment request in the last patch, but it's not the end of the world if it doesn't get added right away. An extra set of eyeballs from Paolo, Jim, and/or Like would be welcome as I don't consider myself trustworthy when it comes to PMU code... Reviewed-by: Sean Christopherson <seanjc@google.com>
On 28/10/2022 6:02 am, Sean Christopherson wrote: >> Aaron Lewis (7): >> kvm: x86/pmu: Correct the mask used in a pmu event filter lookup >> kvm: x86/pmu: Remove impossible events from the pmu event filter >> kvm: x86/pmu: prepare the pmu event filter for masked events >> kvm: x86/pmu: Introduce masked events to the pmu event filter >> selftests: kvm/x86: Add flags when creating a pmu event filter >> selftests: kvm/x86: Add testing for KVM_SET_PMU_EVENT_FILTER >> selftests: kvm/x86: Test masked events > One comment request in the last patch, but it's not the end of the world if it > doesn't get added right away. > > An extra set of eyeballs from Paolo, Jim, and/or Like would be welcome as I don't > consider myself trustworthy when it comes to PMU code... > > Reviewed-by: Sean Christopherson<seanjc@google.com> > I'm not going to block these changes just because I don't use the pmu-event-filter feature very heavily. One of my concern is the relatively lower test coverage of pmu-event-filter involved code, despite its predictable performance optimizations. Maybe a rebase version would attract more attention (or at least mine). Thanks, Like Xu
On Wed, Nov 9, 2022 at 11:28 AM Like Xu <like.xu.linux@gmail.com> wrote: > > On 28/10/2022 6:02 am, Sean Christopherson wrote: > >> Aaron Lewis (7): > >> kvm: x86/pmu: Correct the mask used in a pmu event filter lookup > >> kvm: x86/pmu: Remove impossible events from the pmu event filter > >> kvm: x86/pmu: prepare the pmu event filter for masked events > >> kvm: x86/pmu: Introduce masked events to the pmu event filter > >> selftests: kvm/x86: Add flags when creating a pmu event filter > >> selftests: kvm/x86: Add testing for KVM_SET_PMU_EVENT_FILTER > >> selftests: kvm/x86: Test masked events > > One comment request in the last patch, but it's not the end of the world if it > > doesn't get added right away. > > > > An extra set of eyeballs from Paolo, Jim, and/or Like would be welcome as I don't > > consider myself trustworthy when it comes to PMU code... > > > > Reviewed-by: Sean Christopherson<seanjc@google.com> > > > > I'm not going to block these changes just because I don't use the > pmu-event-filter feature very heavily. > One of my concern is the relatively lower test coverage of pmu-event-filter > involved code, despite its predictable performance optimizations. Is there something else you are hoping to see as far as testing goes other than the selftest? Or is something missing in it? > > Maybe a rebase version would attract more attention (or at least mine). Sure, I'll send out v7 rebased on top of kvm/queue. > > Thanks, > Like Xu
This series introduces the concept of masked events to the pmu event filter. Masked events can help reduce the number of events needed in the pmu event filter by allowing a more generalized matching method to be used for the unit mask when filtering guest events in the pmu. With masked events, if an event select should be restricted from the guest, instead of having to add an entry to the pmu event filter for each event select + unit mask pair, a masked event can be added to generalize the unit mask values. v5 -> v6 - The following changes were based on Sean's feedback. - Patch #1, Use a const for EVENTSEL_EVENT rather than a callback. - Patch #2, s/invalid/impossible and removed helpers. - Patch #3, Ditched internal event struct. Sticking with arch layout. - Patch #4, - Switched masked events to follow arch layout. - Created an internal struct for the pmu event filter. - Track separate lists for include events and exclude events. - General refactors as a result of these changes. v4 -> v5 - Patch #3, Simplified the return logic in filter_contains_match(). [Jim] - Patch #4, Corrected documentation for errors and returns. [Jim] - Patch #6, Added TEST_REQUIRE for KVM_CAP_PMU_EVENT_MASKED_EVENTS. [Jim] - Patch #7, - Removed TEST_REQUIRE for KVM_CAP_PMU_EVENT_MASKED_EVENTS (moved it to patch #6). - Changed the assert to a branch in supports_event_mem_inst_retired(). [Jim] - Added a check to make sure 3 GP counters are available. [Jim] v3 -> v4 - Patch #1, Fix the mask for the guest event select used in bsearch. - Patch #2, Remove invalid events from the pmu event filter. - Patch #3, Create an internal/common representation for filter events. - Patch #4, - Use a common filter event to simplify kernel code. [Jim] - s/invalid/exclude for masked events. More descriptive. [Sean] - Simplified masked event layout. There was no need to complicate it. - Add KVM_CAP_PMU_EVENT_MASKED_EVENTS. - Patch #7, Rewrote the masked events tests using MEM_INST_RETIRED (0xd0) on Intel and LS Dispatch (0x29) on AMD. They have multiple unit masks each which were leveraged for improved masked events testing. v2 -> v3 - Reworked and documented the invert flag usage. It was possible to get ambiguous results when using it. That should not be possible now. - Added testing for inverted masked events to validate the updated implementation. - Removed testing for inverted masked events from the masked events test. They were meaningless with the updated implementation. More meaning tests were added separately. v1 -> v2 - Made has_invalid_event() static to fix warning. - Fixed checkpatch.pl errors and warnings. - Updated to account for KVM_X86_PMU_OP(). Aaron Lewis (7): kvm: x86/pmu: Correct the mask used in a pmu event filter lookup kvm: x86/pmu: Remove impossible events from the pmu event filter kvm: x86/pmu: prepare the pmu event filter for masked events kvm: x86/pmu: Introduce masked events to the pmu event filter selftests: kvm/x86: Add flags when creating a pmu event filter selftests: kvm/x86: Add testing for KVM_SET_PMU_EVENT_FILTER selftests: kvm/x86: Test masked events Documentation/virt/kvm/api.rst | 77 +++- arch/x86/include/asm/kvm_host.h | 14 +- arch/x86/include/uapi/asm/kvm.h | 29 ++ arch/x86/kvm/pmu.c | 241 +++++++++-- arch/x86/kvm/pmu.h | 2 + arch/x86/kvm/svm/pmu.c | 1 + arch/x86/kvm/vmx/pmu_intel.c | 1 + arch/x86/kvm/x86.c | 1 + include/uapi/linux/kvm.h | 1 + .../kvm/x86_64/pmu_event_filter_test.c | 387 +++++++++++++++++- 10 files changed, 703 insertions(+), 51 deletions(-)