x86/hvm: improve "Emulation failed @" error messages

* Introduce hvm_dump_emulation_state() to be a common implementation rather
  than having the printk() open-coded slightly differently in 3 separate
  places.
* Identify the vcpu operating mode to allow for unambiguous decoding of the
  instruction bytes.
* A valid instruction can be up to 15 bytes long, but may also be shorter than
  the current arbitrary 10 bytes.  Print only the fetched bytes, which could
  include nothing if the emulation failed due to an inability to fetch the
  instruction.

A sample new error message looks like:

(d1) MMIO emulation failed: d1v0 64bit @ 0008:ffff82d0802c4f20 -> 48 8b b8 e8 7f 00 00

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Release-acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 463ccfb41856babc8fbb9d40e035e961a6768887..c0f47d2dfee2721bb0a31b1e7af7a7ee9d960998 100644 (file)
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1420,15 +1420,7 @@ void hvm_mem_event_emulate_one(bool_t nowrite, unsigned int trapnr,
          */
         return;
     case X86EMUL_UNHANDLEABLE:
-        gdprintk(XENLOG_DEBUG, "Emulation failed @ %04x:%lx: "
-               "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
-               hvmemul_get_seg_reg(x86_seg_cs, &ctx)->sel,
-               ctx.insn_buf_eip,
-               ctx.insn_buf[0], ctx.insn_buf[1],
-               ctx.insn_buf[2], ctx.insn_buf[3],
-               ctx.insn_buf[4], ctx.insn_buf[5],
-               ctx.insn_buf[6], ctx.insn_buf[7],
-               ctx.insn_buf[8], ctx.insn_buf[9]);
+        hvm_dump_emulation_state(XENLOG_G_DEBUG "Mem event", &ctx);
         hvm_inject_hw_exception(trapnr, errcode);
         break;
     case X86EMUL_EXCEPTION:
@@ -1479,6 +1471,32 @@ struct segment_register *hvmemul_get_seg_reg(
     return &hvmemul_ctxt->seg_reg[seg];
 }
 
+static const char *guest_x86_mode_to_str(int mode)
+{
+    switch ( mode )
+    {
+    case 0:  return "Real";
+    case 1:  return "v86";
+    case 2:  return "16bit";
+    case 4:  return "32bit";
+    case 8:  return "64bit";
+    default: return "Unknown";
+    }
+}
+
+void hvm_dump_emulation_state(const char *prefix,
+                              struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+    struct vcpu *curr = current;
+    const char *mode_str = guest_x86_mode_to_str(hvm_guest_x86_mode(curr));
+    const struct segment_register *cs =
+        hvmemul_get_seg_reg(x86_seg_cs, hvmemul_ctxt);
+
+    printk("%s emulation failed: %pv %s @ %04x:%08lx -> %*ph\n",
+           prefix, curr, mode_str, cs->sel, hvmemul_ctxt->insn_buf_eip,
+           hvmemul_ctxt->insn_buf_bytes, hvmemul_ctxt->insn_buf);
+}
+
 /*
  * Local variables:
  * mode: C

diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index e5d5e796ff242179aaa4d083881298c0ebd0377f..68fb89036aaa74f9a93f285f947e8080dac0be30 100644 (file)
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -100,16 +100,7 @@ int handle_mmio(void)
     switch ( rc )
     {
     case X86EMUL_UNHANDLEABLE:
-        gdprintk(XENLOG_WARNING,
-                 "MMIO emulation failed @ %04x:%lx: "
-                 "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
-                 hvmemul_get_seg_reg(x86_seg_cs, &ctxt)->sel,
-                 ctxt.insn_buf_eip,
-                 ctxt.insn_buf[0], ctxt.insn_buf[1],
-                 ctxt.insn_buf[2], ctxt.insn_buf[3],
-                 ctxt.insn_buf[4], ctxt.insn_buf[5],
-                 ctxt.insn_buf[6], ctxt.insn_buf[7],
-                 ctxt.insn_buf[8], ctxt.insn_buf[9]);
+        hvm_dump_emulation_state(XENLOG_G_WARNING "MMIO", &ctxt);
         return 0;
     case X86EMUL_EXCEPTION:
         if ( ctxt.exn_pending )

diff --git a/xen/arch/x86/hvm/vmx/realmode.c b/xen/arch/x86/hvm/vmx/realmode.c
index 9a6de6c4416e822c8bd1a99d1bc45da15a43ad8a..fe8b4a032fb449bec894a6c9c20183440fbc8696 100644 (file)
--- a/xen/arch/x86/hvm/vmx/realmode.c
+++ b/xen/arch/x86/hvm/vmx/realmode.c
@@ -157,14 +157,7 @@ static void realmode_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt)
     return;
 
  fail:
-    gdprintk(XENLOG_ERR,
-             "Real-mode emulation failed @ %04x:%08lx: "
-             "%02x %02x %02x %02x %02x %02x\n",
-             hvmemul_get_seg_reg(x86_seg_cs, hvmemul_ctxt)->sel,
-             hvmemul_ctxt->insn_buf_eip,
-             hvmemul_ctxt->insn_buf[0], hvmemul_ctxt->insn_buf[1],
-             hvmemul_ctxt->insn_buf[2], hvmemul_ctxt->insn_buf[3],
-             hvmemul_ctxt->insn_buf[4], hvmemul_ctxt->insn_buf[5]);
+    hvm_dump_emulation_state(XENLOG_G_ERR "Real-mode", hvmemul_ctxt);
     domain_crash(curr->domain);
 }
 

diff --git a/xen/include/asm-x86/hvm/emulate.h b/xen/include/asm-x86/hvm/emulate.h
index 6cdc57b9240ee6e171c7de46f13d6a3ca88a30ef..5411302eeff54e16c7b510388370a9197329b137 100644 (file)
--- a/xen/include/asm-x86/hvm/emulate.h
+++ b/xen/include/asm-x86/hvm/emulate.h
@@ -54,4 +54,7 @@ int hvmemul_do_pio(
     unsigned long port, unsigned long *reps, int size,
     paddr_t ram_gpa, int dir, int df, void *p_data);
 
+void hvm_dump_emulation_state(const char *prefix,
+                              struct hvm_emulate_ctxt *hvmemul_ctxt);
+
 #endif /* __ASM_X86_HVM_EMULATE_H__ */