From: Jan Kiszka <[email protected]> A VCPU sending INIT or SIPI to some other VCPU races for setting the remote VCPU's mp_state. When we were unlucky, KVM_MP_STATE_INIT_RECEIVED was overwritten by kvm_emulate_halt and, thus, got lost.
Fix this by raising requests on the sender side that will then be handled synchronously over the target VCPU context. Signed-off-by: Jan Kiszka <[email protected]> --- Changes in v2: - check transition to INIT_RECEIVED in vcpu_enter_guest - removed return value of kvm_check_init_and_sipi - caller has to check for relevant transition afterward - add write barrier after setting sipi_vector arch/x86/kvm/lapic.c | 11 ++++++----- arch/x86/kvm/x86.c | 15 +++++++++++++++ include/linux/kvm_host.h | 2 ++ 3 files changed, 23 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 02b51dd..7986c9f 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -731,8 +731,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, case APIC_DM_INIT: if (!trig_mode || level) { result = 1; - vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; - kvm_make_request(KVM_REQ_EVENT, vcpu); + kvm_make_request(KVM_REQ_INIT, vcpu); kvm_vcpu_kick(vcpu); } else { apic_debug("Ignoring de-assert INIT to vcpu %d\n", @@ -743,11 +742,13 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, case APIC_DM_STARTUP: apic_debug("SIPI to vcpu %d vector 0x%02x\n", vcpu->vcpu_id, vector); - if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { + if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED || + test_bit(KVM_REQ_INIT, &vcpu->requests)) { result = 1; vcpu->arch.sipi_vector = vector; - vcpu->arch.mp_state = KVM_MP_STATE_SIPI_RECEIVED; - kvm_make_request(KVM_REQ_EVENT, vcpu); + /* make sure sipi_vector is visible for the receiver */ + smp_wmb(); + kvm_make_request(KVM_REQ_SIPI, vcpu); kvm_vcpu_kick(vcpu); } break; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d0cf737..0be04b9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5641,6 +5641,15 @@ static void update_eoi_exitmap(struct kvm_vcpu *vcpu) kvm_x86_ops->load_eoi_exitmap(vcpu, eoi_exit_bitmap); } +static void kvm_check_init_and_sipi(struct kvm_vcpu *vcpu) +{ + if (kvm_check_request(KVM_REQ_INIT, vcpu)) + vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; + if (kvm_check_request(KVM_REQ_SIPI, vcpu) && + vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) + vcpu->arch.mp_state = KVM_MP_STATE_SIPI_RECEIVED; +} + static int vcpu_enter_guest(struct kvm_vcpu *vcpu) { int r; @@ -5649,6 +5658,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) bool req_immediate_exit = 0; if (vcpu->requests) { + kvm_check_init_and_sipi(vcpu); + if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { + r = 1; + goto out; + } if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu)) kvm_mmu_unload(vcpu); if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu)) @@ -6977,6 +6991,7 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm, int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) { + kvm_check_init_and_sipi(vcpu); return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && !vcpu->arch.apf.halted) || !list_empty_careful(&vcpu->async_pf.done) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 722cae7..1a191c9 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -124,6 +124,8 @@ static inline bool is_error_page(struct page *page) #define KVM_REQ_MCLOCK_INPROGRESS 20 #define KVM_REQ_EPR_EXIT 21 #define KVM_REQ_EOIBITMAP 22 +#define KVM_REQ_INIT 23 +#define KVM_REQ_SIPI 24 #define KVM_USERSPACE_IRQ_SOURCE_ID 0 #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID 1 -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
