Re: [Qemu-devel] [PATCH v2 1/2] vl: allow other threads to do qemu_system_vmstop_request

[Eric Blake <eblake@redhat.com>]

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On 06/05/2014 06:53 AM, Paolo Bonzini wrote:
> There patch protects vmstop_requested with a lock and introduces

s/There/This/ ?

> qemu_system_vmstop_request_prepare.
> 
> Together with the new call to qemu_vmstop_requested in vm_start,
> qemu_system_vmstop_request_prepare avoids a race where the VM could remain
> stopped even though the iostatus of a block device has already been set
> (for example).
> 
> qemu_system_vmstop_request_prepare however also lets the caller thread
> delay observation of the state change until it has itself communicated
> that change to the user.  This delay avoids any possibility of a wrong
> reordering of the BLOCK_IO_ERROR event and the subsequent STOP event.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  cpus.c                  |  1 +
>  include/sysemu/sysemu.h |  1 +
>  target-lm32/op_helper.c |  2 +-
>  vl.c                    | 85 +++++++++++++++++++++++++++++++------------------
>  4 files changed, 57 insertions(+), 32 deletions(-)
> 

Not my area of code expertise, so take this with a grain of salt:
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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