From: Wanpeng Li Date: Tue, 11 Jun 2019 12:23:50 +0000 (+0800) Subject: KVM: X86: Expose PV_SCHED_YIELD CPUID feature bit to guest X-Git-Tag: v5.3-rc1~115^2~28 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=32b72ecc83b651fb8633ac4bd44957c54367699d;p=linux.git KVM: X86: Expose PV_SCHED_YIELD CPUID feature bit to guest Expose PV_SCHED_YIELD feature bit to guest, the guest can check this feature bit before using paravirtualized sched yield. Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Liran Alon Signed-off-by: Wanpeng Li Signed-off-by: Paolo Bonzini --- diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt index 97ca1940a0dc..979a77ba5377 100644 --- a/Documentation/virtual/kvm/cpuid.txt +++ b/Documentation/virtual/kvm/cpuid.txt @@ -66,6 +66,10 @@ KVM_FEATURE_PV_SEND_IPI || 11 || guest checks this feature bit || || before using paravirtualized || || send IPIs. ------------------------------------------------------------------------------ +KVM_FEATURE_PV_SCHED_YIELD || 13 || guest checks this feature bit + || || before using paravirtualized + || || sched yield. +------------------------------------------------------------------------------ KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side || || per-cpu warps are expected in || || kvmclock. diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 68c74e948e28..004cbd84c351 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -659,7 +659,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, (1 << KVM_FEATURE_PV_TLB_FLUSH) | (1 << KVM_FEATURE_ASYNC_PF_VMEXIT) | (1 << KVM_FEATURE_PV_SEND_IPI) | - (1 << KVM_FEATURE_POLL_CONTROL); + (1 << KVM_FEATURE_POLL_CONTROL) | + (1 << KVM_FEATURE_PV_SCHED_YIELD); if (sched_info_on()) entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);