diff options
Diffstat (limited to 'arch/x86/kvm/x86.c')
-rw-r--r-- | arch/x86/kvm/x86.c | 47 |
1 files changed, 42 insertions, 5 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6200d5a51f13..279ab4e8dd82 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9775,6 +9775,36 @@ static int apf_get_user(struct kvm_vcpu *vcpu, u32 *val) sizeof(u32)); } +static bool kvm_can_deliver_async_pf(struct kvm_vcpu *vcpu) +{ + if (!vcpu->arch.apf.delivery_as_pf_vmexit && is_guest_mode(vcpu)) + return false; + + if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) || + (vcpu->arch.apf.send_user_only && + kvm_x86_ops->get_cpl(vcpu) == 0)) + return false; + + return true; +} + +bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu) +{ + if (unlikely(!lapic_in_kernel(vcpu) || + kvm_event_needs_reinjection(vcpu) || + vcpu->arch.exception.pending)) + return false; + + if (kvm_hlt_in_guest(vcpu->kvm) && !kvm_can_deliver_async_pf(vcpu)) + return false; + + /* + * If interrupts are off we cannot even use an artificial + * halt state. + */ + return kvm_x86_ops->interrupt_allowed(vcpu); +} + void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) { @@ -9783,11 +9813,8 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, trace_kvm_async_pf_not_present(work->arch.token, work->gva); kvm_add_async_pf_gfn(vcpu, work->arch.gfn); - if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) || - (vcpu->arch.apf.send_user_only && - kvm_x86_ops->get_cpl(vcpu) == 0)) - kvm_make_request(KVM_REQ_APF_HALT, vcpu); - else if (!apf_put_user(vcpu, KVM_PV_REASON_PAGE_NOT_PRESENT)) { + if (kvm_can_deliver_async_pf(vcpu) && + !apf_put_user(vcpu, KVM_PV_REASON_PAGE_NOT_PRESENT)) { fault.vector = PF_VECTOR; fault.error_code_valid = true; fault.error_code = 0; @@ -9795,6 +9822,16 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, fault.address = work->arch.token; fault.async_page_fault = true; kvm_inject_page_fault(vcpu, &fault); + } else { + /* + * It is not possible to deliver a paravirtualized asynchronous + * page fault, but putting the guest in an artificial halt state + * can be beneficial nevertheless: if an interrupt arrives, we + * can deliver it timely and perhaps the guest will schedule + * another process. When the instruction that triggered a page + * fault is retried, hopefully the page will be ready in the host. + */ + kvm_make_request(KVM_REQ_APF_HALT, vcpu); } } |