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Re: [Xen-devel] [PATCH 01/02] Handles broken page occurred before migration



[snip]
> 
> If you use scope restricted local variables (which I appreciate),
> please declare them in the innermost possible scope, ...
> 
>> +
>> +        d = rcu_lock_domain_by_id(domctl->domain); +        if ( d
>> != NULL ) +        {
>> +            pfn = domctl->u.set_broken_page_p2m.pfn; +
>> +            mfn = get_gfn_query(d, pfn, &pt);
> 
> ... i.e. here (and then both assignments can become initializers
> at once).
> 
>> +            if ( !mfn_valid(mfn_x(mfn)) || !p2m_is_ram(pt) ) +     
>> { +                put_gfn(d, pfn);
>> +                rcu_unlock_domain(d);
>> +                ret = -EINVAL;
>> +                break;
>> +            }
>> +
>> +            if ( p2m_change_type(d, pfn, pt, p2m_ram_broken) != pt )
>> +                ret = -EINVAL;
> 
> The two if() conditions can be easily joined (the more that they
> both produce -EINVAL).
> 

Thanks, updated as attached.

Jinsong

======================

Handles broken page occurred before migration

This patch handles guest broken page which occurred before migration.

At sender, the broken page would be mapped but not copied to target
(otherwise it may trigger more serious error, say, 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 access the broken page again, it would kill itself as expected.

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

diff -r e84a79d11d7a tools/libxc/xc_domain.c
--- a/tools/libxc/xc_domain.c   Thu Nov 01 01:41:03 2012 +0800
+++ b/tools/libxc/xc_domain.c   Thu Nov 01 07:52:41 2012 +0800
@@ -283,6 +283,22 @@
     return ret;
 }
 
+/* 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 e84a79d11d7a tools/libxc/xc_domain_restore.c
--- a/tools/libxc/xc_domain_restore.c   Thu Nov 01 01:41:03 2012 +0800
+++ b/tools/libxc/xc_domain_restore.c   Thu Nov 01 07:52:41 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 failed, "
+                      "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 e84a79d11d7a tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c      Thu Nov 01 01:41:03 2012 +0800
+++ b/tools/libxc/xc_domain_save.c      Thu Nov 01 07:52:41 2012 +0800
@@ -1277,6 +1277,13 @@
                 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 )
@@ -1371,8 +1378,12 @@
                     }
                 }
 
-                /* 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 e84a79d11d7a tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h     Thu Nov 01 01:41:03 2012 +0800
+++ b/tools/libxc/xenctrl.h     Thu Nov 01 07:52:41 2012 +0800
@@ -575,6 +575,17 @@
                           xc_domaininfo_t *info);
 
 /**
+ * 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 e84a79d11d7a xen/arch/x86/domctl.c
--- a/xen/arch/x86/domctl.c     Thu Nov 01 01:41:03 2012 +0800
+++ b/xen/arch/x86/domctl.c     Thu Nov 01 07:52:41 2012 +0800
@@ -209,12 +209,18 @@
                 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
                     {
                         switch( page->u.inuse.type_info & PGT_type_mask )
@@ -235,6 +241,9 @@
 
                         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 )
@@ -1568,6 +1577,29 @@
     }
     break;
 
+    case XEN_DOMCTL_set_broken_page_p2m:
+    {
+        struct domain *d;
+        
+        d = rcu_lock_domain_by_id(domctl->domain);
+        if ( d != NULL )
+        {
+            p2m_type_t pt;
+            unsigned long pfn = domctl->u.set_broken_page_p2m.pfn;
+            mfn_t mfn = get_gfn_query(d, pfn, &pt);
+
+            if ( unlikely(!mfn_valid(mfn_x(mfn)) || !p2m_is_ram(pt) ||
+                         (p2m_change_type(d, pfn, pt, p2m_ram_broken) != pt)) )
+                ret = -EINVAL;
+
+            put_gfn(d, pfn);
+            rcu_unlock_domain(d);
+        }
+        else
+            ret = -ESRCH;
+    }
+    break;
+
     default:
         ret = iommu_do_domctl(domctl, u_domctl);
         break;
diff -r e84a79d11d7a xen/include/public/domctl.h
--- a/xen/include/public/domctl.h       Thu Nov 01 01:41:03 2012 +0800
+++ b/xen/include/public/domctl.h       Thu Nov 01 07:52:41 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)
 
@@ -835,6 +836,12 @@
 typedef struct xen_domctl_set_access_required xen_domctl_set_access_required_t;
 DEFINE_XEN_GUEST_HANDLE(xen_domctl_set_access_required_t);
 
+struct xen_domctl_set_broken_page_p2m {
+    uint64_aligned_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
@@ -900,6 +907,7 @@
 #define XEN_DOMCTL_set_access_required           64
 #define XEN_DOMCTL_audit_p2m                     65
 #define XEN_DOMCTL_set_virq_handler              66
+#define XEN_DOMCTL_set_broken_page_p2m           67
 #define XEN_DOMCTL_gdbsx_guestmemio            1000
 #define XEN_DOMCTL_gdbsx_pausevcpu             1001
 #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
@@ -955,6 +963,7 @@
         struct xen_domctl_audit_p2m         audit_p2m;
         struct xen_domctl_set_virq_handler  set_virq_handler;
         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: broken_page_occur_before_migration.patch
Description: broken_page_occur_before_migration.patch

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