Commit 2d5b5a66 authored by Sheng Yang's avatar Sheng Yang Committed by Avi Kivity
Browse files

KVM: x86: XSAVE/XRSTOR live migration support 



This patch enable save/restore of xsave state.

Signed-off-by: default avatarSheng Yang <sheng@linux.intel.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 69b61833

Documentation/kvm/api.txt

+74 −0
Original line number Diff line number Diff line
@@ -922,6 +922,80 @@ Define which vcpu is the Bootstrap Processor (BSP). Values are the same 
as the vcpu id in KVM_CREATE_VCPU.  If this ioctl is not called, the default

is vcpu 0.



4.41 KVM_GET_XSAVE



Capability: KVM_CAP_XSAVE

Architectures: x86

Type: vcpu ioctl

Parameters: struct kvm_xsave (out)

Returns: 0 on success, -1 on error



struct kvm_xsave {

	__u32 region[1024];

};



This ioctl would copy current vcpu's xsave struct to the userspace.



4.42 KVM_SET_XSAVE



Capability: KVM_CAP_XSAVE

Architectures: x86

Type: vcpu ioctl

Parameters: struct kvm_xsave (in)

Returns: 0 on success, -1 on error



struct kvm_xsave {

	__u32 region[1024];

};



This ioctl would copy userspace's xsave struct to the kernel.



4.43 KVM_GET_XCRS



Capability: KVM_CAP_XCRS

Architectures: x86

Type: vcpu ioctl

Parameters: struct kvm_xcrs (out)

Returns: 0 on success, -1 on error



struct kvm_xcr {

	__u32 xcr;

	__u32 reserved;

	__u64 value;

};



struct kvm_xcrs {

	__u32 nr_xcrs;

	__u32 flags;

	struct kvm_xcr xcrs[KVM_MAX_XCRS];

	__u64 padding[16];

};



This ioctl would copy current vcpu's xcrs to the userspace.



4.44 KVM_SET_XCRS



Capability: KVM_CAP_XCRS

Architectures: x86

Type: vcpu ioctl

Parameters: struct kvm_xcrs (in)

Returns: 0 on success, -1 on error



struct kvm_xcr {

	__u32 xcr;

	__u32 reserved;

	__u64 value;

};



struct kvm_xcrs {

	__u32 nr_xcrs;

	__u32 flags;

	struct kvm_xcr xcrs[KVM_MAX_XCRS];

	__u64 padding[16];

};



This ioctl would set vcpu's xcr to the value userspace specified.



5. The kvm_run structure



Application code obtains a pointer to the kvm_run structure by

arch/x86/include/asm/kvm.h

+22 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ 
#define __KVM_HAVE_XEN_HVM

#define __KVM_HAVE_VCPU_EVENTS

#define __KVM_HAVE_DEBUGREGS

#define __KVM_HAVE_XSAVE

#define __KVM_HAVE_XCRS



/* Architectural interrupt line count. */

#define KVM_NR_INTERRUPTS 256
@@ -299,4 +301,24 @@ struct kvm_debugregs { 
	__u64 reserved[9];

};



/* for KVM_CAP_XSAVE */

struct kvm_xsave {

	__u32 region[1024];

};



#define KVM_MAX_XCRS	16



struct kvm_xcr {

	__u32 xcr;

	__u32 reserved;

	__u64 value;

};



struct kvm_xcrs {

	__u32 nr_xcrs;

	__u32 flags;

	struct kvm_xcr xcrs[KVM_MAX_XCRS];

	__u64 padding[16];

};



#endif /* _ASM_X86_KVM_H */

arch/x86/include/asm/xsave.h

+5 −2
Original line number Diff line number Diff line
@@ -13,8 +13,11 @@ 


#define FXSAVE_SIZE	512



#define XSTATE_YMM_SIZE 256

#define XSTATE_YMM_OFFSET (512 + 64)

#define XSAVE_HDR_SIZE	    64

#define XSAVE_HDR_OFFSET    FXSAVE_SIZE



#define XSAVE_YMM_SIZE	    256

#define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)



/*

 * These are the features that the OS can handle currently.

arch/x86/kvm/x86.c

+139 −0
Original line number Diff line number Diff line
@@ -1680,6 +1680,7 @@ int kvm_dev_ioctl_check_extension(long ext) 
	case KVM_CAP_PCI_SEGMENT:

	case KVM_CAP_DEBUGREGS:

	case KVM_CAP_X86_ROBUST_SINGLESTEP:

	case KVM_CAP_XSAVE:

		r = 1;

		break;

	case KVM_CAP_COALESCED_MMIO:
@@ -1703,6 +1704,9 @@ int kvm_dev_ioctl_check_extension(long ext) 
	case KVM_CAP_MCE:

		r = KVM_MAX_MCE_BANKS;

		break;

	case KVM_CAP_XCRS:

		r = cpu_has_xsave;

		break;

	default:

		r = 0;

		break;
@@ -2355,6 +2359,77 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu, 
	return 0;

}



static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,

					 struct kvm_xsave *guest_xsave)

{

	if (cpu_has_xsave)

		memcpy(guest_xsave->region,

			&vcpu->arch.guest_fpu.state->xsave,

			sizeof(struct xsave_struct));

	else {

		memcpy(guest_xsave->region,

			&vcpu->arch.guest_fpu.state->fxsave,

			sizeof(struct i387_fxsave_struct));

		*(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] =

			XSTATE_FPSSE;

	}

}



static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,

					struct kvm_xsave *guest_xsave)

{

	u64 xstate_bv =

		*(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)];



	if (cpu_has_xsave)

		memcpy(&vcpu->arch.guest_fpu.state->xsave,

			guest_xsave->region, sizeof(struct xsave_struct));

	else {

		if (xstate_bv & ~XSTATE_FPSSE)

			return -EINVAL;

		memcpy(&vcpu->arch.guest_fpu.state->fxsave,

			guest_xsave->region, sizeof(struct i387_fxsave_struct));

	}

	return 0;

}



static void kvm_vcpu_ioctl_x86_get_xcrs(struct kvm_vcpu *vcpu,

					struct kvm_xcrs *guest_xcrs)

{

	if (!cpu_has_xsave) {

		guest_xcrs->nr_xcrs = 0;

		return;

	}



	guest_xcrs->nr_xcrs = 1;

	guest_xcrs->flags = 0;

	guest_xcrs->xcrs[0].xcr = XCR_XFEATURE_ENABLED_MASK;

	guest_xcrs->xcrs[0].value = vcpu->arch.xcr0;

}



static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu,

				       struct kvm_xcrs *guest_xcrs)

{

	int i, r = 0;



	if (!cpu_has_xsave)

		return -EINVAL;



	if (guest_xcrs->nr_xcrs > KVM_MAX_XCRS || guest_xcrs->flags)

		return -EINVAL;



	for (i = 0; i < guest_xcrs->nr_xcrs; i++)

		/* Only support XCR0 currently */

		if (guest_xcrs->xcrs[0].xcr == XCR_XFEATURE_ENABLED_MASK) {

			r = __kvm_set_xcr(vcpu, XCR_XFEATURE_ENABLED_MASK,

				guest_xcrs->xcrs[0].value);

			break;

		}

	if (r)

		r = -EINVAL;

	return r;

}



long kvm_arch_vcpu_ioctl(struct file *filp,

			 unsigned int ioctl, unsigned long arg)

{
@@ -2556,6 +2631,70 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
		r = kvm_vcpu_ioctl_x86_set_debugregs(vcpu, &dbgregs);

		break;

	}

	case KVM_GET_XSAVE: {

		struct kvm_xsave *xsave;



		xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);

		r = -ENOMEM;

		if (!xsave)

			break;



		kvm_vcpu_ioctl_x86_get_xsave(vcpu, xsave);



		r = -EFAULT;

		if (copy_to_user(argp, xsave, sizeof(struct kvm_xsave)))

			break;

		r = 0;

		break;

	}

	case KVM_SET_XSAVE: {

		struct kvm_xsave *xsave;



		xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);

		r = -ENOMEM;

		if (!xsave)

			break;



		r = -EFAULT;

		if (copy_from_user(xsave, argp, sizeof(struct kvm_xsave)))

			break;



		r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, xsave);

		break;

	}

	case KVM_GET_XCRS: {

		struct kvm_xcrs *xcrs;



		xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);

		r = -ENOMEM;

		if (!xcrs)

			break;



		kvm_vcpu_ioctl_x86_get_xcrs(vcpu, xcrs);



		r = -EFAULT;

		if (copy_to_user(argp, xcrs,

				 sizeof(struct kvm_xcrs)))

			break;

		r = 0;

		break;

	}

	case KVM_SET_XCRS: {

		struct kvm_xcrs *xcrs;



		xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);

		r = -ENOMEM;

		if (!xcrs)

			break;



		r = -EFAULT;

		if (copy_from_user(xcrs, argp,

				   sizeof(struct kvm_xcrs)))

			break;



		r = kvm_vcpu_ioctl_x86_set_xcrs(vcpu, xcrs);

		break;

	}

	default:

		r = -EINVAL;

	}

include/linux/kvm.h

+12 −0
Original line number Diff line number Diff line
@@ -524,6 +524,12 @@ struct kvm_enable_cap { 
#define KVM_CAP_PPC_OSI 52

#define KVM_CAP_PPC_UNSET_IRQ 53

#define KVM_CAP_ENABLE_CAP 54

#ifdef __KVM_HAVE_XSAVE

#define KVM_CAP_XSAVE 55

#endif

#ifdef __KVM_HAVE_XCRS

#define KVM_CAP_XCRS 56

#endif



#ifdef KVM_CAP_IRQ_ROUTING
@@ -714,6 +720,12 @@ struct kvm_clock_data { 
#define KVM_GET_DEBUGREGS         _IOR(KVMIO,  0xa1, struct kvm_debugregs)

#define KVM_SET_DEBUGREGS         _IOW(KVMIO,  0xa2, struct kvm_debugregs)

#define KVM_ENABLE_CAP            _IOW(KVMIO,  0xa3, struct kvm_enable_cap)

/* Available with KVM_CAP_XSAVE */

#define KVM_GET_XSAVE		  _IOR(KVMIO,  0xa4, struct kvm_xsave)

#define KVM_SET_XSAVE		  _IOW(KVMIO,  0xa5, struct kvm_xsave)

/* Available with KVM_CAP_XCRS */

#define KVM_GET_XCRS		  _IOR(KVMIO,  0xa6, struct kvm_xcrs)

#define KVM_SET_XCRS		  _IOW(KVMIO,  0xa7, struct kvm_xcrs)



#define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)