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[Xen-devel] [PATCH] X86/vMCE: guest broken page handling when migration



X86/vMCE: guest broken page handling when migration

This patch is used to handle guest broken page when migration.

At sender, the broken page would not be mapped, and the error page 
content would not be copied to target, otherwise it may trigger more 
serious error (i.e. SRAR error). While its pfn_type and pfn number 
would be transferred to target so that target take appropriate action.

At target, it would set p2m as p2m_ram_broken for broken page, so that 
if guest crazy access the broken page again, it would kill guest as expected.

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

diff -r b17fb3cb92d2 tools/libxc/xc_domain.c
--- a/tools/libxc/xc_domain.c   Mon Aug 27 05:27:54 2012 +0800
+++ b/tools/libxc/xc_domain.c   Mon Aug 27 23:25:43 2012 +0800
@@ -314,6 +314,22 @@
     return ret ? -1 : 0;
 }
 
+/* set broken page p2m */
+int xc_set_broken_page_p2m(xc_interface *xch,
+                           uint32_t domid,
+                           unsigned long pfn)
+{
+    int ret;
+    DECLARE_DOMCTL;
+
+    domctl.cmd = XEN_DOMCTL_set_broken_page_p2m;
+    domctl.domain = (domid_t)domid;
+    domctl.u.set_broken_page_p2m.pfn = pfn;
+    ret = do_domctl(xch, &domctl);
+
+    return ret ? -1 : 0;
+}
+
 /* get info from hvm guest for save */
 int xc_domain_hvm_getcontext(xc_interface *xch,
                              uint32_t domid,
diff -r b17fb3cb92d2 tools/libxc/xc_domain_restore.c
--- a/tools/libxc/xc_domain_restore.c   Mon Aug 27 05:27:54 2012 +0800
+++ b/tools/libxc/xc_domain_restore.c   Mon Aug 27 23:25:43 2012 +0800
@@ -962,9 +962,15 @@
 
     countpages = count;
     for (i = oldcount; i < buf->nr_pages; ++i)
-        if ((buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == 
XEN_DOMCTL_PFINFO_XTAB
-            ||(buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == 
XEN_DOMCTL_PFINFO_XALLOC)
+    {
+        unsigned long pagetype;
+
+        pagetype = buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK;
+        if ( pagetype == XEN_DOMCTL_PFINFO_XTAB ||
+             pagetype == XEN_DOMCTL_PFINFO_BROKEN ||
+             pagetype == XEN_DOMCTL_PFINFO_XALLOC )
             --countpages;
+    }
 
     if (!countpages)
         return count;
@@ -1200,6 +1206,17 @@
             /* a bogus/unmapped/allocate-only page: skip it */
             continue;
 
+        if ( pagetype == XEN_DOMCTL_PFINFO_BROKEN )
+        {
+            if ( xc_set_broken_page_p2m(xch, dom, pfn) )
+            {
+                ERROR("Set p2m for broken page fail, "
+                      "dom=%d, pfn=%lx\n", dom, pfn);
+                goto err_mapped;
+            }
+            continue;
+        }
+
         if (pfn_err[i])
         {
             ERROR("unexpected PFN mapping failure pfn %lx map_mfn %lx p2m_mfn 
%lx",
diff -r b17fb3cb92d2 tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c      Mon Aug 27 05:27:54 2012 +0800
+++ b/tools/libxc/xc_domain_save.c      Mon Aug 27 23:25:43 2012 +0800
@@ -1285,6 +1285,13 @@
                 if ( !hvm )
                     gmfn = pfn_to_mfn(gmfn);
 
+                if ( pfn_type[j] == XEN_DOMCTL_PFINFO_BROKEN )
+                {
+                    pfn_type[j] |= pfn_batch[j];
+                    ++run;
+                    continue;
+                }
+
                 if ( pfn_err[j] )
                 {
                     if ( pfn_type[j] == XEN_DOMCTL_PFINFO_XTAB )
@@ -1379,8 +1386,12 @@
                     }
                 }
 
-                /* skip pages that aren't present or are alloc-only */
+                /* 
+                 * skip pages that aren't present,
+                 * or are broken, or are alloc-only
+                 */
                 if ( pagetype == XEN_DOMCTL_PFINFO_XTAB
+                    || pagetype == XEN_DOMCTL_PFINFO_BROKEN
                     || pagetype == XEN_DOMCTL_PFINFO_XALLOC )
                     continue;
 
diff -r b17fb3cb92d2 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h     Mon Aug 27 05:27:54 2012 +0800
+++ b/tools/libxc/xenctrl.h     Mon Aug 27 23:25:43 2012 +0800
@@ -588,6 +588,17 @@
                                int *vmce_while_migrate);
 
 /**
+ * This function set p2m for broken page
+ * &parm xch a handle to an open hypervisor interface
+ * @parm domid the domain id which broken page belong to
+ * @parm pfn the pfn number of the broken page
+ * @return 0 on success, -1 on failure
+ */
+int xc_set_broken_page_p2m(xc_interface *xch,
+                           uint32_t domid,
+                           unsigned long pfn);
+
+/**
  * This function returns information about the context of a hvm domain
  * @parm xch a handle to an open hypervisor interface
  * @parm domid the domain to get information from
diff -r b17fb3cb92d2 xen/arch/x86/domctl.c
--- a/xen/arch/x86/domctl.c     Mon Aug 27 05:27:54 2012 +0800
+++ b/xen/arch/x86/domctl.c     Mon Aug 27 23:25:43 2012 +0800
@@ -203,12 +203,18 @@
                 for ( j = 0; j < k; j++ )
                 {
                     unsigned long type = 0;
+                    p2m_type_t t;
 
-                    page = get_page_from_gfn(d, arr[j], NULL, P2M_ALLOC);
+                    page = get_page_from_gfn(d, arr[j], &t, P2M_ALLOC);
 
                     if ( unlikely(!page) ||
                          unlikely(is_xen_heap_page(page)) )
-                        type = XEN_DOMCTL_PFINFO_XTAB;
+                    {
+                        if ( p2m_is_broken(t) )
+                            type = XEN_DOMCTL_PFINFO_BROKEN;
+                        else
+                            type = XEN_DOMCTL_PFINFO_XTAB;
+                    }
                     else if ( xsm_getpageframeinfo(page) != 0 )
                         ;
                     else
@@ -231,6 +237,9 @@
 
                         if ( page->u.inuse.type_info & PGT_pinned )
                             type |= XEN_DOMCTL_PFINFO_LPINTAB;
+
+                        if ( page->count_info & PGC_broken )
+                            type = XEN_DOMCTL_PFINFO_BROKEN;
                     }
 
                     if ( page )
@@ -1552,6 +1561,28 @@
     }
     break;
 
+    case XEN_DOMCTL_set_broken_page_p2m:
+    {
+        struct domain *d;
+        p2m_type_t pt;
+        unsigned long pfn;
+
+        d = rcu_lock_domain_by_id(domctl->domain);
+        if ( d != NULL )
+        {
+            pfn = domctl->u.set_broken_page_p2m.pfn;
+
+            get_gfn_query(d, pfn, &pt);
+            p2m_change_type(d, pfn, pt, p2m_ram_broken);
+            put_gfn(d, pfn);
+
+            rcu_unlock_domain(d);
+        }
+        else
+            ret = -ESRCH;
+    }
+    break;
+
     default:
         ret = iommu_do_domctl(domctl, u_domctl);
         break;
diff -r b17fb3cb92d2 xen/include/public/domctl.h
--- a/xen/include/public/domctl.h       Mon Aug 27 05:27:54 2012 +0800
+++ b/xen/include/public/domctl.h       Mon Aug 27 23:25:43 2012 +0800
@@ -136,6 +136,7 @@
 #define XEN_DOMCTL_PFINFO_LPINTAB (0x1U<<31)
 #define XEN_DOMCTL_PFINFO_XTAB    (0xfU<<28) /* invalid page */
 #define XEN_DOMCTL_PFINFO_XALLOC  (0xeU<<28) /* allocate-only page */
+#define XEN_DOMCTL_PFINFO_BROKEN  (0xdU<<28) /* broken page */
 #define XEN_DOMCTL_PFINFO_PAGEDTAB (0x8U<<28)
 #define XEN_DOMCTL_PFINFO_LTAB_MASK (0xfU<<28)
 
@@ -856,6 +857,12 @@
 typedef struct xen_domctl_vmce_monitor xen_domctl_vmce_monitor_t;
 DEFINE_XEN_GUEST_HANDLE(xen_domctl_vmce_monitor_t);
 
+struct xen_domctl_set_broken_page_p2m {
+    uint64_t pfn;
+};
+typedef struct xen_domctl_set_broken_page_p2m xen_domctl_set_broken_page_p2m_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_set_broken_page_p2m_t);
+
 struct xen_domctl {
     uint32_t cmd;
 #define XEN_DOMCTL_createdomain                   1
@@ -923,6 +930,7 @@
 #define XEN_DOMCTL_set_virq_handler              66
 #define XEN_DOMCTL_vmce_monitor_start            67
 #define XEN_DOMCTL_vmce_monitor_end              68
+#define XEN_DOMCTL_set_broken_page_p2m           69
 #define XEN_DOMCTL_gdbsx_guestmemio            1000
 #define XEN_DOMCTL_gdbsx_pausevcpu             1001
 #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
@@ -980,6 +988,7 @@
         struct xen_domctl_set_virq_handler  set_virq_handler;
         struct xen_domctl_vmce_monitor      vmce_monitor;
         struct xen_domctl_gdbsx_memio       gdbsx_guest_memio;
+        struct xen_domctl_set_broken_page_p2m set_broken_page_p2m;
         struct xen_domctl_gdbsx_pauseunp_vcpu gdbsx_pauseunp_vcpu;
         struct xen_domctl_gdbsx_domstatus   gdbsx_domstatus;
         uint8_t                             pad[128];

Attachment: 9_vmce_migration_pfntype_broken.patch
Description: 9_vmce_migration_pfntype_broken.patch

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