[Xen-devel] [PATCH] mem_event: fix regression affecting CR3, CR4 memory events

[Steven Maresca <steve@xxxxxxxxxxxx>]

This is a patch repairing a regression in code previously functional in 4.1.x. 
It appears that, during some refactoring work, calls to hvm_memory_event_cr3 
and hvm_memory_event_cr4 were lost.

These functions were originally called in mov_to_cr() of vmx.c, but the commit  
http://xenbits.xen.org/hg/xen-unstable.hg/rev/1276926e3795 abstracted the 
original code into generic functions up a level in hvm.c, dropping these calls 
in the process.

Signed-off-by: Steven Maresca <steve@xxxxxxxxxxxx>

diff -r a64f4e107951 -r 4d31c1c86418 xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Fri Sep 07 11:09:46 2012 +0100
+++ b/xen/arch/x86/hvm/hvm.c    Mon Sep 10 16:48:15 2012 -0400
@@ -1758,6 +1758,7 @@ int hvm_set_cr3(unsigned long value)
 {
     struct vcpu *v = current;
     struct page_info *page;
+    unsigned long old;
 
     if ( hvm_paging_enabled(v) && !paging_mode_hap(v->domain) &&
          (value != v->arch.hvm_vcpu.guest_cr[3]) )
@@ -1775,8 +1776,10 @@ int hvm_set_cr3(unsigned long value)
         HVM_DBG_LOG(DBG_LEVEL_VMMU, "Update CR3 value = %lx", value);
     }
 
+    old=v->arch.hvm_vcpu.guest_cr[3];
     v->arch.hvm_vcpu.guest_cr[3] = value;
     paging_update_cr3(v);
+    hvm_memory_event_cr3(value, old);
     return X86EMUL_OKAY;
 
  bad_cr3:
@@ -1818,6 +1821,7 @@ int hvm_set_cr4(unsigned long value)
 
     v->arch.hvm_vcpu.guest_cr[4] = value;
     hvm_update_guest_cr(v, 4);
+    hvm_memory_event_cr4(value, old_cr);
 
     /*
      * Modifying CR4.{PSE,PAE,PGE,SMEP}, or clearing CR4.PCIDE

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