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.
Even if enable qemu interrupt remapping and PV TLB Shootdown, I can still observe ~14% performance boost by ebizzy benchmark for 64 vCPUs VM, the total msr-induced vmexits reduce ~70%. The patchset implements the PV IPIs for vCPUs <= 64 VM, this is really common in cloud environment, after this patchset is applied, I can continue to add > 64 vCPUs VM support and that implementation has to introduce more complex logic. Cc: Paolo Bonzini <[email protected]> Cc: Radim Krčmář <[email protected]> Cc: Vitaly Kuznetsov <[email protected]> Wanpeng Li (2): KVM: X86: Implement PV IPI in linux guest KVM: X86: Implement PV send IPI support Documentation/virtual/kvm/cpuid.txt | 4 +++ arch/x86/include/uapi/asm/kvm_para.h | 1 + arch/x86/kernel/kvm.c | 63 ++++++++++++++++++++++++++++++++++++ arch/x86/kvm/cpuid.c | 3 +- arch/x86/kvm/x86.c | 25 ++++++++++++++ include/uapi/linux/kvm_para.h | 1 + 6 files changed, 96 insertions(+), 1 deletion(-) -- 2.7.4
