[PATCH v2 2/5] KVM: X86: Add last guest interrupt disable state support

Wanpeng Li
2022-04-01T08:11:45Z

Let's get the information whether or not guests disable interruptions.
Except preempt_count, interrupt disable can be treated as another in
critical section scenario.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/x86.c | 3 +++
2 files changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c13c9ed50903..7a3eb2ba1d0f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -857,6 +857,8 @@ struct kvm_vcpu_arch {
bool preempt_count_enabled;
struct gfn_to_hva_cache preempt_count_cache;
} pv_pc;
+ /* guest irq disabled state, valid iff the vCPU is not loaded */
+ bool last_guest_irq_disabled;

/*
* Indicates the guest is trying to write a gfn that contains one or
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f2d2e3d25230..9aa05f79b743 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4584,6 +4584,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

static_call(kvm_x86_vcpu_load)(vcpu, cpu);

+ vcpu->arch.last_guest_irq_disabled = false;
/* Save host pkru register if supported */
vcpu->arch.host_pkru = read_pkru();

@@ -4676,6 +4677,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)

static_call(kvm_x86_vcpu_put)(vcpu);
vcpu->arch.last_host_tsc = rdtsc();
+ vcpu->arch.last_guest_irq_disabled = !static_call(kvm_x86_get_if_flag)(vcpu);
}

static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
@@ -11227,6 +11229,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
vcpu->arch.pending_external_vector = -1;
vcpu->arch.preempted_in_kernel = false;
vcpu->arch.pv_pc.preempt_count_enabled = false;
+ vcpu->arch.last_guest_irq_disabled = false;

#if IS_ENABLED(CONFIG_HYPERV)
vcpu->arch.hv_root_tdp = INVALID_PAGE;
--
2.25.1