From: Rishabh Bhatnagar risbhat@amazon.com
From: Paolo Bonzini pbonzini@redhat.com
commit 54aa83c90198e68eee8b0850c749bc70efb548da upstream.
Similar to the Xen path, only change the vCPU's reported state if the vCPU was actually preempted. The reason for KVM's behavior is that for example optimistic spinning might not be a good idea if the guest is doing repeated exits to userspace; however, it is confusing and unlikely to make a difference, because well-tuned guests will hardly ever exit KVM_RUN in the first place.
Suggested-by: Sean Christopherson seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com [risbhat@amazon.com: Don't check for xen msr as support is not available and skip the SEV-ES condition] Signed-off-by: Rishabh Bhatnagar risbhat@amazon.com Tested-by: Allen Pais apais@linux.microsoft.com Acked-by: Sean Christopherson seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/x86.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4139,16 +4139,18 @@ void kvm_arch_vcpu_put(struct kvm_vcpu * { int idx;
- if (vcpu->preempted) + if (vcpu->preempted) { vcpu->arch.preempted_in_kernel = !kvm_x86_ops.get_cpl(vcpu);
- /* - * kvm_memslots() will be called by - * kvm_write_guest_offset_cached() so take the srcu lock. - */ - idx = srcu_read_lock(&vcpu->kvm->srcu); - kvm_steal_time_set_preempted(vcpu); - srcu_read_unlock(&vcpu->kvm->srcu, idx); + /* + * Take the srcu lock as memslots will be accessed to check the gfn + * cache generation against the memslots generation. + */ + idx = srcu_read_lock(&vcpu->kvm->srcu); + kvm_steal_time_set_preempted(vcpu); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + } + kvm_x86_ops.vcpu_put(vcpu); vcpu->arch.last_host_tsc = rdtsc(); /*