diff mbox

[v5,1/4] KVM: X86: Add vCPU running/preempted state

Message ID 1510567280-19376-2-git-send-email-wanpeng.li@hotmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Wanpeng Li Nov. 13, 2017, 10:01 a.m. UTC 
From: Wanpeng Li <wanpeng.li@hotmail.com>

This patch reuses the preempted field in kvm_steal_time, and will export
the vcpu running/pre-empted information to the guest from host. This will
enable guest to intelligently send ipi to running vcpus and set flag for
pre-empted vcpus. This will prevent waiting for vcpus that are not running.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
 arch/x86/include/uapi/asm/kvm_para.h | 3 +++
 arch/x86/kernel/kvm.c                | 2 +-
 arch/x86/kvm/x86.c                   | 4 ++--
 3 files changed, 6 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 554aa8f..bf17b30 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -51,6 +51,9 @@  struct kvm_steal_time {
 	__u32 pad[11];
 };
 
+#define KVM_VCPU_NOT_PREEMPTED      (0 << 0)
+#define KVM_VCPU_PREEMPTED          (1 << 0)
+
 #define KVM_CLOCK_PAIRING_WALLCLOCK 0
 struct kvm_clock_pairing {
 	__s64 sec;
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 8bb9594..1b1b641 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -608,7 +608,7 @@  __visible bool __kvm_vcpu_is_preempted(long cpu)
 {
 	struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
 
-	return !!src->preempted;
+	return !!(src->preempted & KVM_VCPU_PREEMPTED);
 }
 PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 03869eb..5e63033 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2113,7 +2113,7 @@  static void record_steal_time(struct kvm_vcpu *vcpu)
 		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
 		return;
 
-	vcpu->arch.st.steal.preempted = 0;
+	vcpu->arch.st.steal.preempted = KVM_VCPU_NOT_PREEMPTED;
 
 	if (vcpu->arch.st.steal.version & 1)
 		vcpu->arch.st.steal.version += 1;  /* first time write, random junk */
@@ -2884,7 +2884,7 @@  static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
 	if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
 		return;
 
-	vcpu->arch.st.steal.preempted = 1;
+	vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED;
 
 	kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,
 			&vcpu->arch.st.steal.preempted,