Pavel Dovgalyuk <dovga...@ispras.ru> writes:
>> From: Alex Bennée [mailto:alex.ben...@linaro.org] >> Pavel Dovgalyuk <pavel.dovga...@ispras.ru> 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. I got confused with block device snapshots and rr snapshots. Let me try again ;-) -- Alex Bennée
