On 12/23/2024 2:43 PM, Manali Shukla wrote: > On 12/12/2024 10:07 PM, Manali Shukla wrote: >> On 11/28/2024 8:39 PM, Manali Shukla wrote: >>> On 10/22/2024 11:18 AM, Manali Shukla wrote: >>>> The upcoming new Idle HLT Intercept feature allows for the HLT >>>> instruction execution by a vCPU to be intercepted by the hypervisor >>>> only if there are no pending V_INTR and V_NMI events for the vCPU. >>>> When the vCPU is expected to service the pending V_INTR and V_NMI >>>> events, the Idle HLT intercept won’t trigger. The feature allows the >>>> hypervisor to determine if the vCPU is actually idle and reduces >>>> wasteful VMEXITs. >>>> >>>> The idle HLT intercept feature is used for enlightened guests who wish >>>> to securely handle the events. When an enlightened guest does a HLT >>>> while an interrupt is pending, hypervisor will not have a way to >>>> figure out whether the guest needs to be re-entered or not. The Idle >>>> HLT intercept feature allows the HLT execution only if there are no >>>> pending V_INTR and V_NMI events. >>>> >>>> Presence of the Idle HLT Intercept feature is indicated via CPUID >>>> function Fn8000_000A_EDX[30]. >>>> >>>> Document for the Idle HLT intercept feature is available at [1]. >>>> >>>> This series is based on kvm-next/next (64dbb3a771a1) + [2]. >>>> >>>> Experiments done: >>>> ---------------- >>>> >>>> kvm_amd.avic is set to '0' for this experiment. >>>> >>>> The below numbers represent the average of 10 runs. >>>> >>>> Normal guest (L1) >>>> The below netperf command was run on the guest with smp = 1 (pinned). >>>> >>>> netperf -H <host ip> -t TCP_RR -l 60 >>>> ---------------------------------------------------------------- >>>> |with Idle HLT(transactions/Sec)|w/o Idle HLT(transactions/Sec)| >>>> ---------------------------------------------------------------- >>>> | 25645.7136 | 25773.2796 | >>>> ---------------------------------------------------------------- >>>> >>>> Number of transactions/sec with and without idle HLT intercept feature >>>> are almost same. >>>> >>>> Nested guest (L2) >>>> The below netperf command was run on L2 guest with smp = 1 (pinned). >>>> >>>> netperf -H <host ip> -t TCP_RR -l 60 >>>> ---------------------------------------------------------------- >>>> |with Idle HLT(transactions/Sec)|w/o Idle HLT(transactions/Sec)| >>>> ---------------------------------------------------------------- >>>> | 5655.4468 | 5755.2189 | >>>> ---------------------------------------------------------------- >>>> >>>> Number of transactions/sec with and without idle HLT intercept feature >>>> are almost same. >>>> >>>> Testing Done: >>>> - Tested the functionality for the Idle HLT intercept feature >>>> using selftest svm_idle_hlt_test. >>>> - Tested SEV and SEV-ES guest for the Idle HLT intercept functionality. >>>> - Tested the Idle HLT intercept functionality on nested guest. >>>> >>>> v3 -> v4 >>>> - Drop the patches to add vcpu_get_stat() into a new series [2]. >>>> - Added nested Idle HLT intercept support. >>>> >>>> v2 -> v3 >>>> - Incorporated Andrew's suggestion to structure vcpu_stat_types in >>>> a way that each architecture can share the generic types and also >>>> provide its own. >>>> >>>> v1 -> v2 >>>> - Done changes in svm_idle_hlt_test based on the review comments from Sean. >>>> - Added an enum based approach to get binary stats in vcpu_get_stat() which >>>> doesn't use string to get stat data based on the comments from Sean. >>>> - Added self_halt() and cli() helpers based on the comments from Sean. >>>> >>>> [1]: AMD64 Architecture Programmer's Manual Pub. 24593, April 2024, >>>> Vol 2, 15.9 Instruction Intercepts (Table 15-7: IDLE_HLT). >>>> https://bugzilla.kernel.org/attachment.cgi?id=306250 >>>> >>>> [2]: https://lore.kernel.org/kvm/20241021062226.108657-1-manali.shukla@xxxxxxx/T/#t >>>> >>>> Manali Shukla (4): >>>> x86/cpufeatures: Add CPUID feature bit for Idle HLT intercept >>>> KVM: SVM: Add Idle HLT intercept support >>>> KVM: nSVM: implement the nested idle halt intercept >>>> KVM: selftests: KVM: SVM: Add Idle HLT intercept test >>>> >>>> arch/x86/include/asm/cpufeatures.h | 1 + >>>> arch/x86/include/asm/svm.h | 1 + >>>> arch/x86/include/uapi/asm/svm.h | 2 + >>>> arch/x86/kvm/governed_features.h | 1 + >>>> arch/x86/kvm/svm/nested.c | 7 ++ >>>> arch/x86/kvm/svm/svm.c | 15 +++- >>>> tools/testing/selftests/kvm/Makefile | 1 + >>>> .../selftests/kvm/include/x86_64/processor.h | 1 + >>>> .../selftests/kvm/x86_64/svm_idle_hlt_test.c | 89 +++++++++++++++++++ >>>> 9 files changed, 115 insertions(+), 3 deletions(-) >>>> create mode 100644 tools/testing/selftests/kvm/x86_64/svm_idle_hlt_test.c >>>> >>>> >>>> base-commit: c8d430db8eec7d4fd13a6bea27b7086a54eda6da >>>> prerequisite-patch-id: ca912571db5c004f77b70843b8dd35517ff1267f >>>> prerequisite-patch-id: 164ea3b4346f9e04bc69819278d20f5e1b5df5ed >>>> prerequisite-patch-id: 90d870f426ebc2cec43c0dd89b701ee998385455 >>>> prerequisite-patch-id: 45812b799c517a4521782a1fdbcda881237e1eda >>> >>> A gentle reminder. >>> >>> -Manali >> >> A Gentle reminder. >> >> -Manali >> > > A Gentle reminder. > > -Manali Sorry. I just realized that you have already reviewed the patches. Please ignore the reminder. - Manali
