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Commit 96ad2cc6 authored by Eddie Dong's avatar Eddie Dong Committed by Avi Kivity
Browse files

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: default avatarYaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: default avatarQing He <qing.he@intel.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 6bf9e962

drivers/kvm/irq.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

drivers/kvm/kvm_main.c

+46 −0
Original line number Diff line number Diff line
@@ -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:

		;

	}

drivers/kvm/lapic.c

+13 −0
Original line number Diff line number Diff line
@@ -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);

}

include/linux/kvm.h

+8 −0
Original line number Diff line number Diff line
@@ -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