From: Radim Krčmář <[email protected]> A first step in vcpu->requests encapsulation. Additionally, we now use READ_ONCE() when accessing vcpu->requests, which ensures we always load vcpu->requests when it's accessed. This is important as other threads can change it any time. Also, READ_ONCE() documents that vcpu->requests is used with other threads, likely requiring memory barriers, which it does.
Signed-off-by: Radim Krčmář <[email protected]> [ Documented the new use of READ_ONCE(). ] Signed-off-by: Andrew Jones <[email protected]> --- arch/mips/kvm/trap_emul.c | 2 +- arch/powerpc/kvm/booke.c | 2 +- arch/powerpc/kvm/powerpc.c | 5 ++--- arch/s390/kvm/kvm-s390.c | 2 +- arch/x86/kvm/x86.c | 4 ++-- include/linux/kvm_host.h | 5 +++++ 6 files changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c index b1fa53b252ea..9ac8b1d62643 100644 --- a/arch/mips/kvm/trap_emul.c +++ b/arch/mips/kvm/trap_emul.c @@ -1029,7 +1029,7 @@ static void kvm_trap_emul_check_requests(struct kvm_vcpu *vcpu, int cpu, struct mm_struct *mm; int i; - if (likely(!vcpu->requests)) + if (likely(!kvm_request_pending(vcpu))) return; if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) { diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index ab968f60d14c..c427202b3cbb 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -682,7 +682,7 @@ int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu) kvmppc_core_check_exceptions(vcpu); - if (vcpu->requests) { + if (kvm_request_pending(vcpu)) { /* Exception delivery raised request; start over */ return 1; } diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 378ed9cee1f9..0ce1a219984e 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -52,8 +52,7 @@ EXPORT_SYMBOL_GPL(kvmppc_pr_ops); int kvm_arch_vcpu_runnable(struct kvm_vcpu *v) { - return !!(v->arch.pending_exceptions) || - v->requests; + return !!(v->arch.pending_exceptions) || kvm_request_pending(v); } int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) @@ -105,7 +104,7 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) */ smp_mb(); - if (vcpu->requests) { + if (kvm_request_pending(vcpu)) { /* Make sure we process requests preemptable */ local_irq_enable(); trace_kvm_check_requests(vcpu); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 9ab89f73612a..66c33eb53707 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2396,7 +2396,7 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu) { retry: kvm_s390_vcpu_request_handled(vcpu); - if (!vcpu->requests) + if (!kvm_request_pending(vcpu)) return 0; /* * We use MMU_RELOAD just to re-arm the ipte notifier for the diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 073175e14083..92e643af848e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6720,7 +6720,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) bool req_immediate_exit = false; - if (vcpu->requests) { + if (kvm_request_pending(vcpu)) { if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu)) kvm_mmu_unload(vcpu); if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu)) @@ -6884,7 +6884,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_x86_ops->sync_pir_to_irr(vcpu); } - if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests + if (vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu) || need_resched() || signal_pending(current)) { vcpu->mode = OUTSIDE_GUEST_MODE; smp_wmb(); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 94b12154e67c..b1f7d40a4ca4 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1111,6 +1111,11 @@ static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu) set_bit(req & KVM_REQUEST_MASK, &vcpu->requests); } +static inline bool kvm_request_pending(struct kvm_vcpu *vcpu) +{ + return READ_ONCE(vcpu->requests); +} + static inline bool kvm_test_request(int req, struct kvm_vcpu *vcpu) { return test_bit(req & KVM_REQUEST_MASK, &vcpu->requests); -- 2.9.3 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
