KVM: x86: XSAVE/XRSTOR live migration support

This patch enable save/restore of xsave state.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 159b4ef..ffba03f 100644 (file)
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -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

diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index ff90055..4d8dcbd 100644 (file)
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -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 */

diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 29ee4e4..32c3666 100644 (file)
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -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.

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 795999e..0c8dc96 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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;
        }

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 23ea022..6fd40f5 100644 (file)
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -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)