gdbstub: x86: Support for setting segment registers
This allows to set segment registers via gdb also in system emulation
mode. Basic sanity checks are applied and nothing is changed if they
fail. But screwing up the target via this interface will never be
complicated, so I avoided being too paranoid here.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/gdbstub.c b/gdbstub.c
index c17d14f..24297ba 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -563,6 +563,31 @@
return 0;
}
+static int cpu_x86_gdb_load_seg(CPUState *env, int sreg, uint8_t *mem_buf)
+{
+ uint16_t selector = ldl_p(mem_buf);
+
+ if (selector != env->segs[sreg].selector) {
+#if defined(CONFIG_USER_ONLY)
+ cpu_x86_load_seg(env, sreg, selector);
+#else
+ unsigned int limit, flags;
+ target_ulong base;
+
+ if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) {
+ base = selector << 4;
+ limit = 0xffff;
+ flags = 0;
+ } else {
+ if (!cpu_x86_get_descr_debug(env, selector, &base, &limit, &flags))
+ return 4;
+ }
+ cpu_x86_load_seg_cache(env, sreg, selector, base, limit, flags);
+#endif
+ }
+ return 4;
+}
+
static int cpu_gdb_write_register(CPUState *env, uint8_t *mem_buf, int n)
{
uint32_t tmp;
@@ -590,23 +615,12 @@
env->eflags = ldl_p(mem_buf);
return 4;
-#if defined(CONFIG_USER_ONLY)
-#define LOAD_SEG(index, sreg)\
- tmp = ldl_p(mem_buf);\
- if (tmp != env->segs[sreg].selector)\
- cpu_x86_load_seg(env, sreg, tmp);\
- return 4
-#else
-/* FIXME: Honor segment registers. Needs to avoid raising an exception
- when the selector is invalid. */
-#define LOAD_SEG(index, sreg) return 4
-#endif
- case IDX_SEG_REGS: LOAD_SEG(10, R_CS);
- case IDX_SEG_REGS + 1: LOAD_SEG(11, R_SS);
- case IDX_SEG_REGS + 2: LOAD_SEG(12, R_DS);
- case IDX_SEG_REGS + 3: LOAD_SEG(13, R_ES);
- case IDX_SEG_REGS + 4: LOAD_SEG(14, R_FS);
- case IDX_SEG_REGS + 5: LOAD_SEG(15, R_GS);
+ case IDX_SEG_REGS: return cpu_x86_gdb_load_seg(env, R_CS, mem_buf);
+ case IDX_SEG_REGS + 1: return cpu_x86_gdb_load_seg(env, R_SS, mem_buf);
+ case IDX_SEG_REGS + 2: return cpu_x86_gdb_load_seg(env, R_DS, mem_buf);
+ case IDX_SEG_REGS + 3: return cpu_x86_gdb_load_seg(env, R_ES, mem_buf);
+ case IDX_SEG_REGS + 4: return cpu_x86_gdb_load_seg(env, R_FS, mem_buf);
+ case IDX_SEG_REGS + 5: return cpu_x86_gdb_load_seg(env, R_GS, mem_buf);
case IDX_FP_REGS + 8:
env->fpuc = ldl_p(mem_buf);