[Xen-devel] [PATCH] Add a new p2m type for broken memory

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

Add a new p2m type for broken memory.

Currently, this is used only for EPT guest. When memory assigned to guest is 
poisoned, we will mark it as broken in p2m table, the corresponding EPT entry 
is set as not present. Later, if guest try to access the affected memory, EPT 
violation will happen and Xen hypervisor can trap this access.

Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx>

diff -r 29f0479830cd xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Mon Jul 12 13:12:31 2010 +0800
+++ b/xen/arch/x86/hvm/hvm.c    Mon Jul 12 13:58:55 2010 +0800
@@ -971,6 +971,12 @@ bool_t hvm_hap_nested_page_fault(unsigne
 
     mfn = gfn_to_mfn_type_current(gfn, &p2mt, p2m_guest);
 
+    if ( unlikely(p2mt == p2m_ram_broken) )
+    {
+        domain_crash(current->domain);
+        return 1;
+    }
+
     /*
      * If this GFN is emulated MMIO or marked as read-only, pass the fault
      * to the mmio handler.
diff -r 29f0479830cd xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Mon Jul 12 13:12:31 2010 +0800
+++ b/xen/include/asm-x86/p2m.h Mon Jul 12 13:56:02 2010 +0800
@@ -85,6 +85,7 @@ typedef enum {
     p2m_ram_paging_in = 11,       /* Memory that is being paged in */
     p2m_ram_paging_in_start = 12, /* Memory that is being paged in */
     p2m_ram_shared = 13,          /* Shared or sharable memory */
+    p2m_ram_broken  = 14,        /* broken page, access cause domain crash*/
 } p2m_type_t;
 
 typedef enum {
@@ -132,6 +133,8 @@ typedef enum {
                           | p2m_to_mask(p2m_ram_paging_in))
 
 #define P2M_PAGED_TYPES (p2m_to_mask(p2m_ram_paged))
+
+#define P2M_BROKEN_TYPES (p2m_to_mask(p2m_ram_broken))
 
 /* Shared types */
 /* XXX: Sharable types could include p2m_ram_ro too, but we would need to
@@ -155,6 +158,7 @@ typedef enum {
 #define p2m_is_paged(_t)    (p2m_to_mask(_t) & P2M_PAGED_TYPES)
 #define p2m_is_sharable(_t) (p2m_to_mask(_t) & P2M_SHARABLE_TYPES)
 #define p2m_is_shared(_t)   (p2m_to_mask(_t) & P2M_SHARED_TYPES)
+#define p2m_is_broken(_t)   (p2m_to_mask(_t) & P2M_BROKEN_TYPES)
 
 
 /* Populate-on-demand */
diff -r 29f0479830cd xen/include/asm-x86/page.h
--- a/xen/include/asm-x86/page.h        Mon Jul 12 13:12:31 2010 +0800
+++ b/xen/include/asm-x86/page.h        Mon Jul 12 13:56:21 2010 +0800
@@ -323,6 +323,7 @@ void setup_idle_pagetable(void);
 #define _PAGE_PSE_PAT 0x1000U
 #define _PAGE_PAGED   0x2000U
 #define _PAGE_SHARED  0x4000U
+#define _PAGE_BROKEN  0x8000U
 
 /*
  * Debug option: Ensure that granted mappings are not implicitly unmapped.

Attachment: broken_p2m.patch
Description: broken_p2m.patch

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