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Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging
From: |
Pavel Dovgalyuk |
Subject: |
Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging |
Date: |
Tue, 5 Jun 2018 08:27:33 +0300 |
> From: Alex Bennée [mailto:address@hidden
> Pavel Dovgalyuk <address@hidden> writes:
>
> > Ping?
>
> I started having a look but I ran into this straight away. First I
> recorded a boot of the kernel:
>
> ./aarch64-softmmu/qemu-system-aarch64 -machine virt,graphics=on,gic-
> version=3,virtualization=on -cpu cortex-a53 --serial mon:stdio -display none
> -kernel
> ../images/aarch64-current-linux-initrd-guest.img -icount
> shift=7,rr=record,rrfile=replay.bin
>
> Then played back:
>
> ./aarch64-softmmu/qemu-system-aarch64 -machine virt,graphics=on,gic-
> version=3,virtualization=on -cpu cortex-a53 --serial mon:stdio -display none
> -kernel
> ../images/aarch64-current-linux-initrd-guest.img -icount
> shift=7,rr=replay,rrfile=replay.bin -
> s -S
This looks ok, but...
> And did the following on gdb:
>
> (gdb) i
> 0x0000000040000004 in ?? ()
> => 0x40000004: mov x1, xzr
> 0x40000008: mov x2, xzr
> 0x4000000c: mov x3, xzr
> (gdb)
> 0x0000000040000008 in ?? ()
> => 0x40000008: mov x2, xzr
> 0x4000000c: mov x3, xzr
> 0x40000010: ldr x4, 0x40000020
> (gdb)
> 0x000000004000000c in ?? ()
> => 0x4000000c: mov x3, xzr
> 0x40000010: ldr x4, 0x40000020
> 0x40000014: br x4
> (gdb)
> 0x0000000040000010 in ?? ()
> => 0x40000010: ldr x4, 0x40000020
> 0x40000014: br x4
> 0x40000018: .inst 0x44000000 ; undefined
> (gdb)
> 0x0000000040000014 in ?? ()
> => 0x40000014: br x4
> 0x40000018: .inst 0x44000000 ; undefined
> 0x4000001c: .inst 0x00000000 ; undefined
> (gdb) p/x $x4
> $1 = 0x40080000
> (gdb) reverse-stepi
> warning: Remote failure reply: E14
>
> Surely this is the simple case and doesn't require any snapshots for
> block devices as there are none. Am I missing something?
Reverse debugging requires the snapshotting. QEMU can't revert the VM state
without the snapshots.
You can try adding an empty qcow2 image to allow snapshotting there.
Pavel Dovgalyuk
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Pavel Dovgalyuk, 2018/06/04
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Alex Bennée, 2018/06/04
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging,
Pavel Dovgalyuk <=
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Alex Bennée, 2018/06/05
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Alex Bennée, 2018/06/05
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Pavel Dovgalyuk, 2018/06/05
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Alex Bennée, 2018/06/05
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Pavel Dovgalyuk, 2018/06/06
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Pavel Dovgalyuk, 2018/06/25
- Re: [Qemu-devel] [PATCH v4 00/19] reverse debugging, Alex Bennée, 2018/06/27