[PATCH] x86/domctl: Further fix to XEN_DOMCTL_[gs]etvcpuextstate

[Andrew Cooper <andrew.cooper3@citrix.com>]

Do not clobber errors from certain codepaths.  Clobbering of -EINVAL from
failing "evc->size <= PV_XSAVE_SIZE(_xcr0_accum)" was a pre-existing bug.

However, clobbering -EINVAL/-EFAULT from the get codepath was a bug
unintentionally introduced by 090ca8c1 "x86/domctl: two functional fixes to
XEN_DOMCTL_[gs]etvcpuextstate".

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Jan Beulich <JBeulich@suse.com>

---

The pre-posted version of 090ca8c1 also tried to fix the evc->size race
condition and already had this "ret = 0" removed.  I missed that hunk when
stripping the fixes back, after deciding that the size race condition
shouldn't be fixed.

I should really see about making some hypercall regression tests, in some
copious free time...
---
 xen/arch/x86/domctl.c |    2 --
 1 file changed, 2 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 87af350..d927b59 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1277,8 +1277,6 @@ long arch_do_domctl(
             xfree(receive_buf);
         }
 
-        ret = 0;
-
     vcpuextstate_out:
         if ( domctl->cmd == XEN_DOMCTL_getvcpuextstate )
             copyback = 1;
-- 
1.7.10.4