On 05.05.19 14:06, Ralf Ramsauer wrote:
On 5/5/19 10:25 AM, Jan Kiszka wrote:
On 03.05.19 16:29, Ralf Ramsauer wrote:
Hi,
On 4/23/18 6:18 PM, Jan Kiszka wrote:
From: Jan Kiszka <[email protected]>
The parser my bail out on opcode byte 0-2.
Signed-off-by: Jan Kiszka <[email protected]>
---
hypervisor/arch/x86/mmio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hypervisor/arch/x86/mmio.c b/hypervisor/arch/x86/mmio.c
index c1b9f10e8..775ec4b7b 100644
--- a/hypervisor/arch/x86/mmio.c
+++ b/hypervisor/arch/x86/mmio.c
@@ -219,7 +219,7 @@ error_noinst:
error_unsupported:
panic_printk("FATAL: unsupported instruction "
- "(0x%02x [0x%02x] 0x%02x 0x%02x)\n",
+ "(0x%02x 0x%02x 0x%02x 0x%02x)\n",
op[0].raw, op[1].raw, op[2].raw, op[3].raw);
sorry for digging out this old patch, but I think we have a logical bug
here:
There are cases, where we jump to error_unsupported before all opcodes
are set. In this case, the Hypervisor reports the wrong instruction,
which really confused us for a while (Andrej found this).
Yes, this is a known limitation, and the patch here just tried to reduce
the
level of confusion a bit. Before that patch, the output suggested that
we are
always at opcode byte 2. But we can fail at any byte.
This is an expert debug tool. You are expected to parse the opcode bytes
yourself from left to right. And as soon as you hit an opcode that is no
longer
supported by us, you know that the succeeding zeros are invalid. If you
want to
full instruction, use RIP and disassemble the guest. Adding that logic
to the
hypervisor is not planned.
Okay -- maybe we could strike out (0xXX) unknown bytes and simply count
successfully parsed ops. This would at least give a hint that sth. went
wrong.
We could also do full instruction parsing - if that didn't blow up the code
base...
Jan
--
You received this message because you are subscribed to the Google Groups
"Jailhouse" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
