[PATCH 073/104] KVM: in-kernel LAPIC save and restore support

Avi Kivity
2007-09-17T08:46:34Z

From: Eddie Dong <eddie.dong@intel.com>

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>
---
drivers/kvm/irq.h | 1 +
drivers/kvm/kvm_main.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/kvm/lapic.c | 13 +++++++++++++
include/linux/kvm.h | 8 ++++++++
4 files changed, 68 insertions(+), 0 deletions(-)

diff --git a/drivers/kvm/irq.h b/drivers/kvm/irq.h
index 30adddc..24b871f 100644
--- a/drivers/kvm/irq.h
+++ b/drivers/kvm/irq.h
@@ -149,6 +149,7 @@ int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest);
void kvm_ioapic_update_eoi(struct kvm *kvm, int vector);
int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda);
int kvm_apic_set_irq(struct kvm_lapic *apic, u8 vec, u8 trig);
+void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu);
int kvm_ioapic_init(struct kvm *kvm);
void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level);

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 @@ static int kvm_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
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 @@ static long kvm_vcpu_ioctl(struct file *filp,
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:
;
}
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
index 4b5c77d..df636bf 100644
--- a/drivers/kvm/lapic.c
+++ b/drivers/kvm/lapic.c
@@ -931,3 +931,16 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
apic_clear_irr(vector, apic);
return vector;
}
+
+void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->apic;
+
+ apic->base_address = vcpu->apic_base &
+ MSR_IA32_APICBASE_BASE;
+ apic_set_reg(apic, APIC_LVR, APIC_VERSION);
+ apic_update_ppr(apic);
+ hrtimer_cancel(&apic->timer.dev);
+ update_divide_count(apic);
+ start_apic_timer(apic);
+}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 42d1515..30a8369 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -208,6 +208,12 @@ struct kvm_fpu {
__u32 pad2;
};

+/* for KVM_GET_LAPIC and KVM_SET_LAPIC */
+#define KVM_APIC_REG_SIZE 0x400
+struct kvm_lapic_state {
+ char regs[KVM_APIC_REG_SIZE];
+};
+
struct kvm_segment {
__u64 base;
__u32 limit;
@@ -380,5 +386,7 @@ struct kvm_signal_mask {
#define KVM_SET_SIGNAL_MASK _IOW(KVMIO, 0x8b, struct kvm_signal_mask)
#define KVM_GET_FPU _IOR(KVMIO, 0x8c, struct kvm_fpu)
#define KVM_SET_FPU _IOW(KVMIO, 0x8d, struct kvm_fpu)
+#define KVM_GET_LAPIC _IOR(KVMIO, 0x8e, struct kvm_lapic_state)
+#define KVM_SET_LAPIC _IOW(KVMIO, 0x8f, struct kvm_lapic_state)

#endif
--
1.5.3