Re: [Xen-devel] [PATCHv3 1/2] x86/ept: invalidate guest physical mappings on VMENTER

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 14/12/15 14:41, David Vrabel wrote:
> On 07/12/15 10:25, George Dunlap wrote:
>>
>> I took the past tense ("synced") to mean, "These CPUs have been
>> brought into sync (or are no longer out of sync)".  So they start out
>> not-synced, so you initialize the bit to be clear; when an INVEPT is
>> executed, they become synced, so you set the bit; and when you change
>> the EPT tables, they are no longer synced so you clear the bit.
> 
> It didn't work like that though.  I have retained the changed name and
> meaning.

I'm not sure what you mean here.  vmx_ctx_switch_to() would check to see
if the bit corresponding to the current cpu was set; if it wasn't, it
would set the bit and call INVEPT flush.  The mask started out zero
(which would cause a sync on all cpus); and in the original version of
ept_sync_domain(), all the cpus which were about to be synced by the
on_selected_cpus() call are set while the other ones are clear.

 -George

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