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authorSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>2013-08-26 14:18:34 +0530
committerGleb Natapov <gleb@redhat.com>2013-08-26 12:47:09 +0300
commit6aef266c6e17b798a1740cf70cd34f90664740b3 (patch)
tree9b051ea02c2e12ec289f7465a5eefc807ca6f710 /arch/x86/kvm
parent4b0a8670852c1f577014bf2dc4f8a9d1fd908bb9 (diff)
kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks
kvm_hc_kick_cpu allows the calling vcpu to kick another vcpu out of halt state. the presence of these hypercalls is indicated to guest via kvm_feature_pv_unhalt. Fold pv_unhalt flag into GET_MP_STATE ioctl to aid migration During migration, any vcpu that got kicked but did not become runnable (still in halted state) should be runnable after migration. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Suzuki Poulose <suzuki@in.ibm.com> [Raghu: Apic related changes, folding pvunhalted into vcpu_runnable Added flags for future use (suggested by Gleb)] [ Raghu: fold pv_unhalt flag as suggested by Eric Northup] Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: Gleb Natapov <gleb@redhat.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/cpuid.c3
-rw-r--r--arch/x86/kvm/x86.c44
2 files changed, 45 insertions, 2 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index a20ecb5b6cbf..b110fe6c03d4 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -413,7 +413,8 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
(1 << KVM_FEATURE_CLOCKSOURCE2) |
(1 << KVM_FEATURE_ASYNC_PF) |
(1 << KVM_FEATURE_PV_EOI) |
- (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
+ (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
+ (1 << KVM_FEATURE_PV_UNHALT);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 668f19aee6ca..c53741764492 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5588,6 +5588,36 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
return 1;
}
+/*
+ * kvm_pv_kick_cpu_op: Kick a vcpu.
+ *
+ * @apicid - apicid of vcpu to be kicked.
+ */
+static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid)
+{
+ struct kvm_vcpu *vcpu = NULL;
+ int i;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (!kvm_apic_present(vcpu))
+ continue;
+
+ if (kvm_apic_match_dest(vcpu, 0, 0, apicid, 0))
+ break;
+ }
+ if (vcpu) {
+ /*
+ * Setting unhalt flag here can result in spurious runnable
+ * state when unhalt reset does not happen in vcpu_block.
+ * But that is harmless since that should soon result in halt.
+ */
+ vcpu->arch.pv.pv_unhalted = true;
+ /* We need everybody see unhalt before vcpu unblocks */
+ smp_wmb();
+ kvm_vcpu_kick(vcpu);
+ }
+}
+
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
@@ -5621,6 +5651,10 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
case KVM_HC_VAPIC_POLL_IRQ:
ret = 0;
break;
+ case KVM_HC_KICK_CPU:
+ kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1);
+ ret = 0;
+ break;
default:
ret = -KVM_ENOSYS;
break;
@@ -6043,6 +6077,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
kvm_apic_accept_events(vcpu);
switch(vcpu->arch.mp_state) {
case KVM_MP_STATE_HALTED:
+ vcpu->arch.pv.pv_unhalted = false;
vcpu->arch.mp_state =
KVM_MP_STATE_RUNNABLE;
case KVM_MP_STATE_RUNNABLE:
@@ -6342,7 +6377,12 @@ int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state)
{
kvm_apic_accept_events(vcpu);
- mp_state->mp_state = vcpu->arch.mp_state;
+ if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED &&
+ vcpu->arch.pv.pv_unhalted)
+ mp_state->mp_state = KVM_MP_STATE_RUNNABLE;
+ else
+ mp_state->mp_state = vcpu->arch.mp_state;
+
return 0;
}
@@ -6863,6 +6903,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
BUG_ON(vcpu->kvm == NULL);
kvm = vcpu->kvm;
+ vcpu->arch.pv.pv_unhalted = false;
vcpu->arch.emulate_ctxt.ops = &emulate_ops;
if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))
vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
@@ -7200,6 +7241,7 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
!vcpu->arch.apf.halted)
|| !list_empty_careful(&vcpu->async_pf.done)
|| kvm_apic_has_events(vcpu)
+ || vcpu->arch.pv.pv_unhalted
|| atomic_read(&vcpu->arch.nmi_queued) ||
(kvm_arch_interrupt_allowed(vcpu) &&
kvm_cpu_has_interrupt(vcpu));