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Commit b8836737 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: Add fpu get/set operations 



These are really helpful when migrating an floating point app to another
machine.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent e8207547

drivers/kvm/kvm_main.c

+86 −0
Original line number Diff line number Diff line
@@ -2398,6 +2398,67 @@ static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset) 
	return 0;

}



/*

 * fxsave fpu state.  Taken from x86_64/processor.h.  To be killed when

 * we have asm/x86/processor.h

 */

struct fxsave {

	u16	cwd;

	u16	swd;

	u16	twd;

	u16	fop;

	u64	rip;

	u64	rdp;

	u32	mxcsr;

	u32	mxcsr_mask;

	u32	st_space[32];	/* 8*16 bytes for each FP-reg = 128 bytes */

#ifdef CONFIG_X86_64

	u32	xmm_space[64];	/* 16*16 bytes for each XMM-reg = 256 bytes */

#else

	u32	xmm_space[32];	/* 8*16 bytes for each XMM-reg = 128 bytes */

#endif

};



static int kvm_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)

{

	struct fxsave *fxsave = (struct fxsave *)vcpu->guest_fx_image;



	vcpu_load(vcpu);



	memcpy(fpu->fpr, fxsave->st_space, 128);

	fpu->fcw = fxsave->cwd;

	fpu->fsw = fxsave->swd;

	fpu->ftwx = fxsave->twd;

	fpu->last_opcode = fxsave->fop;

	fpu->last_ip = fxsave->rip;

	fpu->last_dp = fxsave->rdp;

	memcpy(fpu->xmm, fxsave->xmm_space, sizeof fxsave->xmm_space);



	vcpu_put(vcpu);



	return 0;

}



static int kvm_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)

{

	struct fxsave *fxsave = (struct fxsave *)vcpu->guest_fx_image;



	vcpu_load(vcpu);



	memcpy(fxsave->st_space, fpu->fpr, 128);

	fxsave->cwd = fpu->fcw;

	fxsave->swd = fpu->fsw;

	fxsave->twd = fpu->ftwx;

	fxsave->fop = fpu->last_opcode;

	fxsave->rip = fpu->last_ip;

	fxsave->rdp = fpu->last_dp;

	memcpy(fxsave->xmm_space, fpu->xmm, sizeof fxsave->xmm_space);



	vcpu_put(vcpu);



	return 0;

}



static long kvm_vcpu_ioctl(struct file *filp,

			   unsigned int ioctl, unsigned long arg)

{
@@ -2542,6 +2603,31 @@ static long kvm_vcpu_ioctl(struct file *filp, 
		r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);

		break;

	}

	case KVM_GET_FPU: {

		struct kvm_fpu fpu;



		memset(&fpu, 0, sizeof fpu);

		r = kvm_vcpu_ioctl_get_fpu(vcpu, &fpu);

		if (r)

			goto out;

		r = -EFAULT;

		if (copy_to_user(argp, &fpu, sizeof fpu))

			goto out;

		r = 0;

		break;

	}

	case KVM_SET_FPU: {

		struct kvm_fpu fpu;



		r = -EFAULT;

		if (copy_from_user(&fpu, argp, sizeof fpu))

			goto out;

		r = kvm_vcpu_ioctl_set_fpu(vcpu, &fpu);

		if (r)

			goto out;

		r = 0;

		break;

	}

	default:

		;

	}

include/linux/kvm.h

+17 −0
Original line number Diff line number Diff line
@@ -126,6 +126,21 @@ struct kvm_regs { 
	__u64 rip, rflags;

};



/* for KVM_GET_FPU and KVM_SET_FPU */

struct kvm_fpu {

	__u8  fpr[8][16];

	__u16 fcw;

	__u16 fsw;

	__u8  ftwx;  /* in fxsave format */

	__u8  pad1;

	__u16 last_opcode;

	__u64 last_ip;

	__u64 last_dp;

	__u8  xmm[16][16];

	__u32 mxcsr;

	__u32 pad2;

};



struct kvm_segment {

	__u64 base;

	__u32 limit;
@@ -285,5 +300,7 @@ struct kvm_signal_mask { 
#define KVM_SET_MSRS              _IOW(KVMIO,  0x89, struct kvm_msrs)

#define KVM_SET_CPUID             _IOW(KVMIO,  0x8a, struct kvm_cpuid)

#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)



#endif