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x86: show cr2 and cr4 along with other register state

PATCH New Jan Beulich 1 participant 1 message Aug 25, 2006

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PATCH 1/1 x86: show cr2 and cr4 along with other register state

Especially cr2 is quite helpful when trying to understand the context of a (forced) domain crash.

xen/arch/x86/hvm/svm/svm.c +1 -0
Index: 2006-08-16/xen/arch/x86/hvm/svm/svm.c
===================================================================
@@ -246,6 +246,7 @@ static void svm_store_cpu_guest_regs(
     {
         /* Returning the guest's regs */
         crs[0] = v->arch.hvm_svm.cpu_shadow_cr0;
+        crs[2] = v->arch.hvm_svm.cpu_cr2;
         crs[3] = v->arch.hvm_svm.cpu_cr3;
         crs[4] = v->arch.hvm_svm.cpu_shadow_cr4;
     }
xen/arch/x86/hvm/vmx/vmx.c +1 -0
Index: 2006-08-16/xen/arch/x86/hvm/vmx/vmx.c
===================================================================
@@ -523,6 +523,7 @@ static void vmx_store_cpu_guest_regs(
     if ( crs != NULL )
     {
         __vmread(CR0_READ_SHADOW, &crs[0]);
+        crs[2] = v->arch.hvm_vmx.cpu_cr2;
         __vmread(GUEST_CR3, &crs[3]);
         __vmread(CR4_READ_SHADOW, &crs[4]);
     }
xen/arch/x86/traps.c +1 -2
Index: 2006-08-16/xen/arch/x86/traps.c
===================================================================
@@ -324,7 +324,6 @@ void show_execution_state(struct cpu_use
 asmlinkage void fatal_trap(int trapnr, struct cpu_user_regs *regs)
 {
     int cpu = smp_processor_id();
-    unsigned long cr2;
     static char *trapstr[] = { 
         "divide error", "debug", "nmi", "bkpt", "overflow", "bounds", 
         "invalid opcode", "device not available", "double fault", 
@@ -341,7 +340,7 @@ asmlinkage void fatal_trap(int trapnr, s
 
     if ( trapnr == TRAP_page_fault )
     {
-        __asm__ __volatile__ ("mov %%cr2,%0" : "=r" (cr2) : );
+        unsigned long cr2 = read_cr2();
         printk("Faulting linear address: %p\n", _p(cr2));
         show_page_walk(cr2);
     }
xen/arch/x86/x86_32/traps.c +11 -3
Index: 2006-08-16/xen/arch/x86/x86_32/traps.c
===================================================================
@@ -35,20 +35,27 @@ void show_registers(struct cpu_user_regs
     }
     else
     {
-        context = guest_mode(regs) ? "guest" : "hypervisor";
-
         if ( !guest_mode(regs) )
         {
+            context = "hypervisor";
             fault_regs.esp = (unsigned long)&regs->esp;
             fault_regs.ss = read_segment_register(ss);
             fault_regs.ds = read_segment_register(ds);
             fault_regs.es = read_segment_register(es);
             fault_regs.fs = read_segment_register(fs);
             fault_regs.gs = read_segment_register(gs);
+            fault_crs[2] = read_cr2();
+        }
+        else
+        {
+            context = "guest";
+            fault_crs[2] = container_of(regs, struct cpu_info, guest_cpu_user_regs)
+                           ->current_vcpu->vcpu_info->arch.cr2;
         }
 
         fault_crs[0] = read_cr0();
         fault_crs[3] = read_cr3();
+        fault_crs[4] = read_cr4();
     }
 
     printk("----[ Xen-%d.%d%s    %s ]----\n",
@@ -63,7 +70,8 @@ void show_registers(struct cpu_user_regs
            fault_regs.eax, fault_regs.ebx, fault_regs.ecx, fault_regs.edx);
     printk("esi: %08x   edi: %08x   ebp: %08x   esp: %08x\n",
            fault_regs.esi, fault_regs.edi, fault_regs.ebp, fault_regs.esp);
-    printk("cr0: %08lx   cr3: %08lx\n", fault_crs[0], fault_crs[3]);
+    printk("cr0: %08lx   cr4: %08lx   cr3: %08lx   cr2: %08lx\n",
+           fault_crs[0], fault_crs[4], fault_crs[3], fault_crs[2]);
     printk("ds: %04x   es: %04x   fs: %04x   gs: %04x   "
            "ss: %04x   cs: %04x\n",
            fault_regs.ds, fault_regs.es, fault_regs.fs,
xen/arch/x86/x86_64/traps.c +15 -3
Index: 2006-08-16/xen/arch/x86/x86_64/traps.c
===================================================================
@@ -35,9 +35,20 @@ void show_registers(struct cpu_user_regs
     }
     else
     {
-        context = guest_mode(regs) ? "guest" : "hypervisor";
+        if ( guest_mode(regs) )
+        {
+            context = "guest";
+            fault_crs[2] = container_of(regs, struct cpu_info, guest_cpu_user_regs)
+                           ->current_vcpu->vcpu_info->arch.cr2;
+        }
+        else
+        {
+            context = "hypervisor";
+            fault_crs[2] = read_cr2();
+        }
         fault_crs[0] = read_cr0();
         fault_crs[3] = read_cr3();
+        fault_crs[4] = read_cr4();
         fault_regs.ds = read_segment_register(ds);
         fault_regs.es = read_segment_register(es);
         fault_regs.fs = read_segment_register(fs);
@@ -62,8 +73,9 @@ void show_registers(struct cpu_user_regs
            fault_regs.r9,  fault_regs.r10, fault_regs.r11);
     printk("r12: %016lx   r13: %016lx   r14: %016lx\n",
            fault_regs.r12, fault_regs.r13, fault_regs.r14);
-    printk("r15: %016lx   cr0: %016lx   cr3: %016lx\n",
-           fault_regs.r15, fault_crs[0], fault_crs[3]);
+    printk("r15: %016lx   cr0: %016lx   cr4: %016lx\n",
+           fault_regs.r15, fault_crs[0], fault_crs[4]);
+    printk("cr3: %016lx   cr2: %016lx\n", fault_crs[3], fault_crs[2]);
     printk("ds: %04x   es: %04x   fs: %04x   gs: %04x   "
            "ss: %04x   cs: %04x\n",
            fault_regs.ds, fault_regs.es, fault_regs.fs,
xen/include/asm-x86/processor.h +7 -0
Index: 2006-08-16/xen/include/asm-x86/processor.h
===================================================================
@@ -290,6 +290,13 @@ static inline void write_cr0(unsigned lo
 	__asm__("mov %0,%%cr0": :"r" ((unsigned long)val)); 
 }
 
+static inline unsigned long read_cr2(void)
+{
+    unsigned long __cr2;
+    __asm__("mov %%cr2,%0\n\t" :"=r" (__cr2));
+    return __cr2;
+}
+
 static inline unsigned long read_cr4(void)
 {
 	unsigned long __cr4;

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