Re: [PATCH] kvm: sync cpu state on internal error before dump

Gleb Natapov
2013-08-23T12:58:53Z

On Fri, Aug 23, 2013 at 01:26:00PM +0100, James Hogan wrote:
> When a KVM internal error occurs QEMU dumps the CPU state, however it
> doesn't synchronise the state from KVM first so the dumped state is out
> of date. Add the synchronisation calls before the dump in both locations
> (which is used depends on whether the arch says to stop or not).
>
x86_cpu_dump_state() calls cpu_synchronize_state() already.

> Note that x86 does a sync in its kvm_arch_stop_on_emulation_error()
> function so at least for emulation errors is unaffected.
>
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Gleb Natapov <gleb@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: kvm@vger.kernel.org
> ---
> kvm-all.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index b788fcd..803141a 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -1546,6 +1546,7 @@ static int kvm_handle_internal_error(CPUState *cpu, struct kvm_run *run)
> if (run->internal.suberror == KVM_INTERNAL_ERROR_EMULATION) {
> fprintf(stderr, "emulation failure\n");
> if (!kvm_arch_stop_on_emulation_error(cpu)) {
> + kvm_cpu_synchronize_state(cpu);
> cpu_dump_state(cpu, stderr, fprintf, CPU_DUMP_CODE);
> return EXCP_INTERRUPT;
> }
> @@ -1701,6 +1702,7 @@ int kvm_cpu_exec(CPUState *cpu)
> } while (ret == 0);
>
> if (ret < 0) {
> + kvm_cpu_synchronize_state(cpu);
> cpu_dump_state(cpu, stderr, fprintf, CPU_DUMP_CODE);
> vm_stop(RUN_STATE_INTERNAL_ERROR);
> }
> --
> 1.8.1.2
>

--
Gleb.