File 23978-xenpaging_check_p2mt_in_p2m_mem_paging_fu... of Package xen

Overview Repositories Revisions Requests Users Attributes Meta

File 23978-xenpaging_check_p2mt_in_p2m_mem_paging_functions.patch of Package xen

changeset:   23978:fd3fa0a85020
user:        Olaf Hering <olaf@aepfle.de>
date:        Thu Oct 20 11:25:55 2011 +0100
files:       xen/arch/x86/mm/p2m.c
description:
xenpaging: check p2mt in p2m_mem_paging functions

Add checks to forward the p2m_ram_paging* state properly during page-in.

Resume can be called several times if several vcpus called populate for
the gfn. Finish resume only once.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Tim Deegan <tim@xen.org>

---
 xen/arch/x86/mm/p2m.c |   20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

Index: xen-4.1.2-testing/xen/arch/x86/mm/p2m.c
===================================================================
--- xen-4.1.2-testing.orig/xen/arch/x86/mm/p2m.c
+++ xen-4.1.2-testing/xen/arch/x86/mm/p2m.c
@@ -3020,16 +3020,22 @@ int p2m_mem_paging_prep(struct p2m_domai
     p2m_type_t p2mt;
     p2m_access_t a;
     mfn_t mfn;
-    int ret = -ENOMEM;
+    int ret;
 
     p2m_lock(p2m);
 
     mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, p2m_query);
 
+    ret = -ENOENT;
+    /* Allow only missing pages */
+    if ( p2mt != p2m_ram_paging_in_start )
+        goto out;
+
     /* Allocate a page if the gfn does not have one yet */
     if ( !mfn_valid(mfn) )
     {
         /* Get a free page */
+        ret = -ENOMEM;
         page = alloc_domheap_page(p2m->domain, 0);
         if ( unlikely(page == NULL) )
             goto out;
@@ -3064,9 +3070,15 @@ void p2m_mem_paging_resume(struct p2m_do
     {
         p2m_lock(p2m);
         mfn = p2m->get_entry(p2m, rsp.gfn, &p2mt, &a, p2m_query);
-        set_p2m_entry(p2m, rsp.gfn, mfn, 0, p2m_ram_rw, a);
-        set_gpfn_from_mfn(mfn_x(mfn), rsp.gfn);
-        audit_p2m(p2m, 1);
+        /* Allow only pages which were prepared properly, or pages which
+         * were nominated but not evicted */
+        if ( mfn_valid(mfn) && 
+             (p2mt == p2m_ram_paging_in || p2mt == p2m_ram_paging_in_start) )
+        {
+            set_p2m_entry(p2m, rsp.gfn, mfn, 0, p2m_ram_rw, a);
+            set_gpfn_from_mfn(mfn_x(mfn), rsp.gfn);
+            audit_p2m(p2m, 1);
+        }
         p2m_unlock(p2m);
     }

Places

File 23978-xenpaging_check_p2mt_in_p2m_mem_paging_functions.patch of Package xen

Places