Gentle ping, hope this series can catch up with the next merge window. :) On Tue, 3 Jul 2018 at 14:21, Wanpeng Li <kernellwp@xxxxxxxxx> wrote: > > Using hypercall to send IPIs by one vmexit instead of one by one for > xAPIC/x2APIC physical mode and one vmexit per-cluster for x2APIC cluster > mode. Intel guest can enter x2apic cluster mode when interrupt remmaping > is enabled in qemu, however, latest AMD EPYC still just supports xapic > mode which can get great improvement by PV IPIs. This patchset supports > PV IPIs for maximal 128 vCPUs VM, it is big enough for cloud environment > currently, supporting more vCPUs needs to introduce more complex logic, > in the future this might be extended if needed. > > Hardware: Xeon Skylake 2.5GHz, 2 sockets, 40 cores, 80 threads, the VM > is 80 vCPUs, IPI microbenchmark(https://lkml.org/lkml/2017/12/19/141): > > x2apic cluster mode, vanilla > > Dry-run: 0, 2392199 ns > Self-IPI: 6907514, 15027589 ns > Normal IPI: 223910476, 251301666 ns > Broadcast IPI: 0, 9282161150 ns > Broadcast lock: 0, 8812934104 ns > > x2apic cluster mode, pv-ipi > > Dry-run: 0, 2449341 ns > Self-IPI: 6720360, 15028732 ns > Normal IPI: 228643307, 255708477 ns > Broadcast IPI: 0, 7572293590 ns => 22% performance boost > Broadcast lock: 0, 8316124651 ns > > x2apic physical mode, vanilla > > Dry-run: 0, 3135933 ns > Self-IPI: 8572670, 17901757 ns > Normal IPI: 226444334, 255421709 ns > Broadcast IPI: 0, 19845070887 ns > Broadcast lock: 0, 19827383656 ns > > x2apic physical mode, pv-ipi > > Dry-run: 0, 2446381 ns > Self-IPI: 6788217, 15021056 ns > Normal IPI: 219454441, 249583458 ns > Broadcast IPI: 0, 7806540019 ns => 154% performance boost > Broadcast lock: 0, 9143618799 ns > > v2 -> v3: > * rename ipi_mask_done to irq_restore_exit, __send_ipi_mask return int > instead of bool > * fix build errors reported by 0day > * split patches, nothing change > > v1 -> v2: > * sparse apic id > 128, or any other errors, fallback to original apic hooks > * have two bitmask arguments so that one hypercall handles 128 vCPUs > * fix KVM_FEATURE_PV_SEND_IPI doc > * document hypercall > * fix NMI selftest fails > * fix build errors reported by 0day > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> > Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > > Wanpeng Li (6): > KVM: X86: Add kvm hypervisor init time platform setup callback > KVM: X86: Implement PV IPIs in linux guest > KVM: X86: Fallback to original apic hooks when bad happens > KVM: X86: Implement PV IPIs send hypercall > KVM: X86: Add NMI support to PV IPIs > KVM: X86: Expose PV_SEND_IPI CPUID feature bit to guest > > Documentation/virtual/kvm/cpuid.txt | 4 ++ > Documentation/virtual/kvm/hypercalls.txt | 6 ++ > arch/x86/include/uapi/asm/kvm_para.h | 1 + > arch/x86/kernel/kvm.c | 101 +++++++++++++++++++++++++++++++ > arch/x86/kvm/cpuid.c | 3 +- > arch/x86/kvm/x86.c | 42 +++++++++++++ > include/uapi/linux/kvm_para.h | 1 + > 7 files changed, 157 insertions(+), 1 deletion(-) > > -- > 2.7.4 >
