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>

1 files changed, 139 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 795999e1ac19..0c8dc9614e7d 100644
--- 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;
         }