This patch applies to the preempt-hooks branch to enable KVM to function
properly on VMX. With preemption enabled, the KVM context can get scheduled
out at arbitrary points. The preempt-hooks allow us to correctly restore
the host state while being preemptible, but preemption causes problems on the
schedule-in side if the vcpu-task migrates to a new pCPU.
Ideally we can handle the migration scenario better (patch for this in
progress). However, this patch provides correctness in the interim at the
expense of a small amount of flexibility. E.g. we can only migrate when the
vcpu_lock is not held.
Signed-off-by: Gregory Haskins <[EMAIL PROTECTED]>
---
drivers/kvm/kvm.h | 1 +
drivers/kvm/kvm_main.c | 3 +++
2 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 03f374e..d18537c 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -318,6 +318,7 @@ struct kvm_vcpu {
struct vcpu_svm *svm;
};
struct mutex mutex;
+ cpumask_t cpumask;
int cpu;
int launched;
u64 host_tsc;
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index ef67572..4a19f6f 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -245,6 +245,8 @@ static void vcpu_load(struct kvm_vcpu *vcpu)
mutex_lock(&vcpu->mutex);
cpu = get_cpu();
+ vcpu->cpumask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(cpu));
preempt_hook_register(&vcpu->preempt_hook);
kvm_arch_ops->vcpu_load(vcpu, cpu);
put_cpu();
@@ -255,6 +257,7 @@ static void vcpu_put(struct kvm_vcpu *vcpu)
preempt_disable();
kvm_arch_ops->vcpu_put(vcpu);
preempt_hook_unregister(&vcpu->preempt_hook);
+ set_cpus_allowed(current, vcpu->cpumask);
preempt_enable();
mutex_unlock(&vcpu->mutex);
}
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