[Xen-devel] [PATCH] xen: x86: copy back tsc info, not pointer to tsc info in domctl

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

In 38b37ed82705 "x86/domctl: cleanup", XEN_DOMCTL_gettscinfo was
changed to use the standard copyback mechanism.

However the output TSC Info is a guerst handle, i.e. a pointer to the
location for the information, copyback just copies the unchanged
pointer back.

Switch back to fetching the details into a local struct and explicitly
copying it back.

This caused test failures in the Cambridge instance of osstest, but
not for some reason in the production instance.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/arch/x86/domctl.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 684259b..e7da735 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -703,13 +703,16 @@ long arch_do_domctl(
             ret = -EINVAL;
         else
         {
+            xen_guest_tsc_info_t info = { 0 };
+
             domain_pause(d);
-            tsc_get_info(d, &domctl->u.tsc_info.info.tsc_mode,
-                         &domctl->u.tsc_info.info.elapsed_nsec,
-                         &domctl->u.tsc_info.info.gtsc_khz,
-                         &domctl->u.tsc_info.info.incarnation);
+            tsc_get_info(d, &info.tsc_mode,
+                            &info.elapsed_nsec,
+                            &info.gtsc_khz,
+                            &info.incarnation);
+            if ( copy_to_guest(domctl->u.tsc_info.out_info, &info, 1) )
+                ret = -EFAULT;
             domain_unpause(d);
-            copyback = 1;
         }
         break;
 
-- 
1.7.10.4


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