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author | Jan Kiszka <jan.kiszka@siemens.com> | 2013-03-13 12:42:34 +0100 |
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committer | Gleb Natapov <gleb@redhat.com> | 2013-03-13 16:08:10 +0200 |
commit | 66450a21f99636af4fafac2afd33f1a40631bc3a (patch) | |
tree | 81a71a5ad44edcb7317567b2a922e9a861bb2bb8 /arch/x86/kvm/lapic.c | |
parent | 5d218814328da91a27e982748443e7e375e11396 (diff) | |
download | linux-66450a21f99636af4fafac2afd33f1a40631bc3a.tar.bz2 |
KVM: x86: Rework INIT and SIPI handling
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.
This introduces APIC events for those two signals, keeping them in
kvm_apic until kvm_apic_accept_events is run over the target vcpu
context. kvm_apic_has_events reports to kvm_arch_vcpu_runnable if there
are pending events, thus if vcpu blocking should end.
The patch comes with the side effect of effectively obsoleting
KVM_MP_STATE_SIPI_RECEIVED. We still accept it from user space, but
immediately translate it to KVM_MP_STATE_INIT_RECEIVED + KVM_APIC_SIPI.
The vcpu itself will no longer enter the KVM_MP_STATE_SIPI_RECEIVED
state. That also means we no longer exit to user space after receiving a
SIPI event.
Furthermore, we already reset the VCPU on INIT, only fixing up the code
segment later on when SIPI arrives. Moreover, we fix INIT handling for
the BSP: it never enter wait-for-SIPI but directly starts over on INIT.
Tested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
-rw-r--r-- | arch/x86/kvm/lapic.c | 48 |
1 files changed, 40 insertions, 8 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 02b51dd4e4ad..a8e9369f41c5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -731,7 +731,11 @@ 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; + /* assumes that there are only KVM_APIC_INIT/SIPI */ + apic->pending_events = (1UL << KVM_APIC_INIT); + /* make sure pending_events is visible before sending + * the request */ + smp_wmb(); kvm_make_request(KVM_REQ_EVENT, vcpu); kvm_vcpu_kick(vcpu); } else { @@ -743,13 +747,13 @@ 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) { - result = 1; - vcpu->arch.sipi_vector = vector; - vcpu->arch.mp_state = KVM_MP_STATE_SIPI_RECEIVED; - kvm_make_request(KVM_REQ_EVENT, vcpu); - kvm_vcpu_kick(vcpu); - } + result = 1; + apic->sipi_vector = vector; + /* make sure sipi_vector is visible for the receiver */ + smp_wmb(); + set_bit(KVM_APIC_SIPI, &apic->pending_events); + kvm_make_request(KVM_REQ_EVENT, vcpu); + kvm_vcpu_kick(vcpu); break; case APIC_DM_EXTINT: @@ -1860,6 +1864,34 @@ int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data) addr); } +void kvm_apic_accept_events(struct kvm_vcpu *vcpu) +{ + struct kvm_lapic *apic = vcpu->arch.apic; + unsigned int sipi_vector; + + if (!kvm_vcpu_has_lapic(vcpu)) + return; + + if (test_and_clear_bit(KVM_APIC_INIT, &apic->pending_events)) { + kvm_lapic_reset(vcpu); + kvm_vcpu_reset(vcpu); + if (kvm_vcpu_is_bsp(apic->vcpu)) + vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; + else + vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; + } + if (test_and_clear_bit(KVM_APIC_SIPI, &apic->pending_events) && + vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { + /* evaluate pending_events before reading the vector */ + smp_rmb(); + sipi_vector = apic->sipi_vector; + pr_debug("vcpu %d received sipi with vector # %x\n", + vcpu->vcpu_id, sipi_vector); + kvm_vcpu_deliver_sipi_vector(vcpu, sipi_vector); + vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; + } +} + void kvm_lapic_init(void) { /* do not patch jump label more than once per second */ |