[Qemu-devel] [Patch] x86 breakpoints and memory examination

[Eddie Kohler]

Hi all,

The following patch is useful for whole-system mode debugging and breakpoint 
setting on i386 QEMU.  It seems like both breakpoints and memory examination 
used semi-physical addresses, in that neither took account of segment 
translation.  This patch (relative to 0.9.1) adds segment translation.

I'm not sure this is the right way to do it (in fact, I'm sure that the memory 
examination patch is the WRONG way to do it) and would appreciate pointers or 
advice.

Thanks,
Eddie Kohler

diff -ru qemu-0.9.1/target-i386/helper2.c qemu-0.9.1-p/target-i386/helper2.c
--- qemu-0.9.1/target-i386/helper2.c    2008-01-06 11:38:45.000000000 -0800
+++ qemu-0.9.1-p/target-i386/helper2.c  2008-01-12 23:56:34.000000000 -0800
@@ -1081,6 +1081,7 @@
 {
     uint32_t pde_addr, pte_addr;
     uint32_t pde, pte, paddr, page_offset, page_size;
+    addr += env->segs[R_DS].base;
 
     if (env->cr[4] & CR4_PAE_MASK) {
         uint32_t pdpe_addr, pde_addr, pte_addr;
diff -ru qemu-0.9.1/target-i386/translate.c qemu-0.9.1-p/target-i386/translate.c
--- qemu-0.9.1/target-i386/translate.c  2008-01-06 11:38:45.000000000 -0800
+++ qemu-0.9.1-p/target-i386/translate.c        2008-01-13 00:00:23.000000000 
-0800
@@ -6758,7 +6758,7 @@
     for(;;) {
         if (env->nb_breakpoints > 0) {
             for(j = 0; j < env->nb_breakpoints; j++) {
-                if (env->breakpoints[j] == pc_ptr) {
+                if (env->breakpoints[j] == pc_ptr - dc->cs_base) {
                     gen_debug(dc, pc_ptr - dc->cs_base);
                     break;
                 }