On 06/11/2010 07:36 AM, Sheng Yang wrote:
This patch enable save/restore of xsave state.

+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)];
+       int size;
+
+       if (cpu_has_xsave) {
+               if (xstate_bv&  XSTATE_YMM)
+                       size = XSAVE_YMM_OFFSET + XSAVE_YMM_SIZE;
+               else
+                       size = XSAVE_HDR_OFFSET + XSAVE_HDR_SIZE;
+               memcpy(&vcpu->arch.guest_fpu.state->xsave,
+                       guest_xsave->region, size);

This allows userspace to overflow host memory by specifying XSTATE_YMM on a host that doesn't support it.

Better to just use the host's size of the structure.

+       } else {
+               if (xstate_bv&  ~XSTATE_FPSSE)
+                       return -EINVAL;
+               size = sizeof(struct i387_fxsave_struct);
+               memcpy(&vcpu->arch.guest_fpu.state->fxsave,
+                       guest_xsave->region, size);
+       }
+       return 0;
+}
+

+
+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;

Too strict?

+
+       if (guest_xcrs->nr_xcrs>  KVM_MAX_XCRS)
+               return -EFAULT;

EFAULT is for faults during access to userspace.  EINVAL or E2BIG.

Need to ensure flags is 0 for forward compatibility.

+
+       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 = -EFAULT;

EINVAL

+       return r;
+}
+

--
error compiling committee.c: too many arguments to function

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