Re: [Xen-devel] [PATCH] x86/tboot: tboot_shutdown: disable interrupts after map_pages_to_xen

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 09.08.17 at 03:01, <christopher.w.clark@xxxxxxxxx> wrote:
> Move the point where interrupts are disabled in tboot_shutdown
> to slightly later, to after the call to map_pages_to_xen.
> 
> This patch originated in OpenXT with the following report:
> 
> "Disabling interrupts early causes debug assertions.
> 
> This is only seen with debug builds but since it causes assertions it is
> probably a bigger problem. It clearly says in map_pages_to_xen that it
> should not be called with interrupts disabled. Moved disabling to just
> after that call."
> 
> The Xen code comment ahead of map_pages_to_xen notes that the CPU cache
> flushing in map_pages_to_xen differs depending on whether interrupts are
> enabled or not. The flush logic with interrupts enabled is more
> conservative, flushing all CPUs' TLBs/caches, rather than just local.
> This is just before the tboot memory integrity MAC calculation is performed
> in the case of entering S3.
> 
> Original patch author credit: Ross Philipson.
> 
> Signed-off-by: Christopher Clark <christopher.clark6@xxxxxxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel