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KVM: Add fpu get/set operations 

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

Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2007-04-01 16:34:31 +03:00
parent e8207547d2
commit b8836737d9
2 changed files with 103 additions and 0 deletions
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86
drivers/kvm/kvm_main.c
View File

@ -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:
;
}

17
include/linux/kvm.h
View File

@ -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