x86: vMCE save and restore

This patch provides vMCE save/restore when migration.
1. MCG_CAP is well-defined. However, considering future cap extension,
   we keep save/restore logic that Jan implement at c/s 24887;
2. MCi_CTL2 initialized by guestos when booting, so need save/restore
   otherwise guest would surprise;
3. Other MSRs do not need save/restore since they are either error-
   related and pointless to save/restore, or, unified among all vMCE
   platform;

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>

- fix handling of partial data in XEN_DOMCTL_set_ext_vcpucontext
- fix adjustment of xen_domctl_ext_vcpucontext

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Committed-by: Jan Beulich <jbeulich@suse.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index f367ce2b2c..a5836470ea 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -32,6 +32,7 @@
 #error "domctl operations are intended for use by node control tools only"
 #endif
 
+#include <xen/hvm/save.h>
 #include "xen.h"
 #include "grant_table.h"
 
@@ -564,7 +565,14 @@ struct xen_domctl_ext_vcpucontext {
     uint16_t         sysenter_callback_cs;
     uint8_t          syscall32_disables_events;
     uint8_t          sysenter_disables_events;
-    uint64_aligned_t mcg_cap;
+#if defined(__GNUC__)
+    union {
+        uint64_aligned_t mcg_cap;
+        struct hvm_vmce_vcpu vmce;
+    };
+#else
+    struct hvm_vmce_vcpu vmce;
+#endif
 #endif
 };
 typedef struct xen_domctl_ext_vcpucontext xen_domctl_ext_vcpucontext_t;