[PATCH v3 10/16] KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable
From: Sean Christopherson <seanjc@google.com>
Date: 2021-09-22 00:06:43
Also in:
kvm, kvmarm, linux-perf-users, linux-riscv, lkml, xen-devel
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Use the generic kvm_running_vcpu plus a new 'handling_intr_from_guest' variable in kvm_arch_vcpu instead of the semi-redundant current_vcpu. kvm_before/after_interrupt() must be called while the vCPU is loaded, (which protects against preemption), thus kvm_running_vcpu is guaranteed to be non-NULL when handling_intr_from_guest is non-zero. Switching to kvm_get_running_vcpu() will allows moving KVM's perf callbacks to generic code, and the new flag will be used in a future patch to more precisely identify the "NMI from guest" case. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/include/asm/kvm_host.h | 3 +-- arch/x86/kvm/pmu.c | 2 +- arch/x86/kvm/x86.c | 21 ++++++++++++--------- arch/x86/kvm/x86.h | 10 ++++++---- 4 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1080166fc0cf..2d86a2dfc775 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h@@ -763,6 +763,7 @@ struct kvm_vcpu_arch { unsigned nmi_pending; /* NMI queued after currently running handler */ bool nmi_injected; /* Trying to inject an NMI this entry */ bool smi_pending; /* SMI queued after currently running handler */ + u8 handling_intr_from_guest; struct kvm_mtrr mtrr_state; u64 pat;
@@ -1874,8 +1875,6 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu); int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err); void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu); -unsigned int kvm_guest_state(void); - void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size); bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 5b68d4188de0..eef48258e50f 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c@@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event, * woken up. So we should wake it, but this is impossible from * NMI context. Do it from irq work instead. */ - if (!kvm_guest_state()) + if (!kvm_handling_nmi_from_guest(pmc->vcpu)) irq_work_queue(&pmc_to_pmu(pmc)->irq_work); else kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6cc66466f301..24a6faa07442 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c@@ -8264,15 +8264,17 @@ static void kvm_timer_init(void) kvmclock_cpu_online, kvmclock_cpu_down_prep); } -DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu); -EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu); +static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu) +{ + return vcpu && vcpu->arch.handling_intr_from_guest; +} -unsigned int kvm_guest_state(void) +static unsigned int kvm_guest_state(void) { - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); unsigned int state; - if (!vcpu) + if (!kvm_pmi_in_guest(vcpu)) return 0; state = PERF_GUEST_ACTIVE;
@@ -8284,9 +8286,10 @@ unsigned int kvm_guest_state(void) static unsigned long kvm_guest_get_ip(void) { - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); - if (WARN_ON_ONCE(!vcpu)) + /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */ + if (WARN_ON_ONCE(!kvm_pmi_in_guest(vcpu))) return 0; return kvm_rip_read(vcpu);
@@ -8294,10 +8297,10 @@ static unsigned long kvm_guest_get_ip(void) static unsigned int kvm_handle_intel_pt_intr(void) { - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); /* '0' on failure so that the !PT case can use a RET0 static call. */ - if (!vcpu) + if (!kvm_pmi_in_guest(vcpu)) return 0; kvm_make_request(KVM_REQ_PMI, vcpu);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 7d66d63dc55a..a9c107e7c907 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h@@ -387,18 +387,20 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm) return kvm->arch.cstate_in_guest; } -DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu); - static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu) { - __this_cpu_write(current_vcpu, vcpu); + WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 1); } static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) { - __this_cpu_write(current_vcpu, NULL); + WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 0); } +static inline bool kvm_handling_nmi_from_guest(struct kvm_vcpu *vcpu) +{ + return !!vcpu->arch.handling_intr_from_guest; +} static inline bool kvm_pat_valid(u64 data) {
--
2.33.0.464.g1972c5931b-goog
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