xenctx: Teach xenctx how to find the right addresses in real-mode.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>

1 files changed, 30 insertions, 8 deletions

diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c
index 38edb3fb55..127379e671 100644
--- a/tools/xentrace/xenctx.c
+++ b/tools/xentrace/xenctx.c
@@ -42,6 +42,7 @@ typedef unsigned long long guest_word_t;
 int guest_word_size = sizeof (unsigned long);
 /* Word-length of the context record we get from xen */
 int ctxt_word_size = sizeof (unsigned long);
+int guest_protected_mode = 1;
 #elif defined (__ia64__)
 /* On ia64, we can't translate virtual address to physical address.  */
 #define NO_TRANSLATION
@@ -206,6 +207,7 @@ static void read_symbol_table(const char *symtab)
 }
 
 #if defined(__i386__) || defined(__x86_64__)
+#define CR0_PE  0x1
 char *flag_values[22][2] =
 {/*  clear,     set,       bit# */
     { NULL,     "c"    }, // 0        Carry
@@ -371,20 +373,38 @@ static void print_ctx(vcpu_guest_context_any_t *ctx)
         print_ctx_64(&ctx->x64);
 }
 
+#define NONPROT_MODE_SEGMENT_SHIFT 4
+
 static guest_word_t instr_pointer(vcpu_guest_context_any_t *ctx)
 {
-    if (ctxt_word_size == 4) 
-        return ctx->x32.user_regs.eip;
+    guest_word_t r;
+    if (ctxt_word_size == 4)
+    {
+        r = ctx->x32.user_regs.eip;
+
+        if ( !guest_protected_mode )
+            r += ctx->x32.user_regs.cs << NONPROT_MODE_SEGMENT_SHIFT;
+    }
     else 
-        return ctx->x64.user_regs.rip;
+        r = ctx->x64.user_regs.rip;
+
+    return r;
 }
 
 static guest_word_t stack_pointer(vcpu_guest_context_any_t *ctx)
 {
-    if (ctxt_word_size == 4) 
-        return ctx->x32.user_regs.esp;
+    guest_word_t r;
+    if (ctxt_word_size == 4)
+    {
+        r = ctx->x32.user_regs.esp;
+
+        if ( !guest_protected_mode )
+            r += ctx->x32.user_regs.ss << NONPROT_MODE_SEGMENT_SHIFT;
+    }
     else 
-        return ctx->x64.user_regs.rsp;
+        r = ctx->x64.user_regs.rsp;
+    
+    return r;
 }
 
 static guest_word_t frame_pointer(vcpu_guest_context_any_t *ctx)
@@ -688,8 +708,9 @@ static void print_code(vcpu_guest_context_any_t *ctx, int vcpu)
     guest_word_t instr;
     int i;
 
-    printf("Code:\n");
-    instr = instr_pointer(ctx) - 21;
+    instr = instr_pointer(ctx);
+    printf("Code (instr addr %08llx)\n", instr);
+    instr -= 21;
     for(i=0; i<32; i++) {
         unsigned char *c = map_page(ctx, vcpu, instr+i);
         if (instr+i == instr_pointer(ctx))
@@ -835,6 +856,7 @@ static void dump_ctx(int vcpu)
                 exit(-1);
             }
             guest_word_size = (cpuctx.msr_efer & 0x400) ? 8 : 4;
+            guest_protected_mode = (cpuctx.cr0 & CR0_PE);
             /* HVM guest context records are always host-sized */
             if (xc_version(xc_handle, XENVER_capabilities, &xen_caps) != 0) {
                 perror("xc_version");