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Re: [Xen-devel] [PATCH v3 2/2] xen: add update indicator to vcpu_runstate_info



Hi Juergen,

On 17/06/16 06:26, Juergen Gross wrote:
In order to support reading another vcpu's mapped vcpu_runstate_info
an indicator for an occurring update of the runstate information is
needed.

Add the possibility to activate setting this indicator in the highest
bit of state_entry_time via a vm_assist hypercall. When activated the
update indicator will be set before the runstate information is
modified in guest memory and it will be reset after modification is
done. As state_entry_time is guaranteed to be different after each
update the guest can detect any update (either in progress or while
reading the runstate data) by comparing state_entry_time before and
after reading runstate data: in case the values differ or the update
indicator was set the data might be inconsistent and should be reread.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

For the ARM bits:

Acked-by: Julien Grall <julien.grall@xxxxxxx>

Regards,

--
Julien Grall

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