KVM: in-kernel LAPIC save and restore support
This patch adds a new vcpu-based IOCTL to save and restore the local
apic registers for a single vcpu. The kernel only copies the apic page as
a whole, extraction of registers is left to userspace side. On restore, the
APIC timer is restarted from the initial count, this introduces a little
delay, but works fine.
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 61dff55..a012d70 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -2642,6 +2642,27 @@
return 0;
}
+static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
+ struct kvm_lapic_state *s)
+{
+ vcpu_load(vcpu);
+ memcpy(s->regs, vcpu->apic->regs, sizeof *s);
+ vcpu_put(vcpu);
+
+ return 0;
+}
+
+static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
+ struct kvm_lapic_state *s)
+{
+ vcpu_load(vcpu);
+ memcpy(vcpu->apic->regs, s->regs, sizeof *s);
+ kvm_apic_post_state_restore(vcpu);
+ vcpu_put(vcpu);
+
+ return 0;
+}
+
static long kvm_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -2811,6 +2832,31 @@
r = 0;
break;
}
+ case KVM_GET_LAPIC: {
+ struct kvm_lapic_state lapic;
+
+ memset(&lapic, 0, sizeof lapic);
+ r = kvm_vcpu_ioctl_get_lapic(vcpu, &lapic);
+ if (r)
+ goto out;
+ r = -EFAULT;
+ if (copy_to_user(argp, &lapic, sizeof lapic))
+ goto out;
+ r = 0;
+ break;
+ }
+ case KVM_SET_LAPIC: {
+ struct kvm_lapic_state lapic;
+
+ r = -EFAULT;
+ if (copy_from_user(&lapic, argp, sizeof lapic))
+ goto out;
+ r = kvm_vcpu_ioctl_set_lapic(vcpu, &lapic);;
+ if (r)
+ goto out;
+ r = 0;
+ break;
+ }
default:
;
}