[PATCH v3 0/3] KVM: Yield to IPI target if necessary

[Wanpeng Li <kernellwp@gmail.com>]

The idea is from Xen, when sending a call-function IPI-many to vCPUs, 
yield if any of the IPI target vCPUs was preempted. 17% performance 
increasement of ebizzy benchmark can be observed in an over-subscribe 
environment. (w/ kvm-pv-tlb disabled, testing TLB flush call-function 
IPI-many since call-function is not easy to be trigged by userspace 
workload).

v2 -> v3:
 * add bounds-check on dest_id

v1 -> v2:
 * check map is not NULL
 * check map->phys_map[dest_id] is not NULL
 * make kvm_sched_yield static
 * change dest_id to unsinged long

Wanpeng Li (3):
  KVM: X86: Yield to IPI target if necessary
  KVM: X86: Implement PV sched yield hypercall
  KVM: X86: Expose PV_SCHED_YIELD CPUID feature bit to guest

 Documentation/virtual/kvm/cpuid.txt      |  4 ++++
 Documentation/virtual/kvm/hypercalls.txt | 11 +++++++++++
 arch/x86/include/uapi/asm/kvm_para.h     |  1 +
 arch/x86/kernel/kvm.c                    | 21 +++++++++++++++++++++
 arch/x86/kvm/cpuid.c                     |  3 ++-
 arch/x86/kvm/x86.c                       | 26 ++++++++++++++++++++++++++
 include/uapi/linux/kvm_para.h            |  1 +
 7 files changed, 66 insertions(+), 1 deletion(-)

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2.7.4