On Mon, Mar 7, 2016 at 10:31 AM, Corneliu ZUZU <cz...@bitdefender.com> wrote:
> On 3/7/2016 11:12 AM, Tamas K Lengyel wrote: > > EPT is not really required for CR3 monitoring, it just has been the case > that vm_events have been only implemented for hap-enabled domains. > > > I suppose this is not valid for vm-events in their entirety, right? I mean > it seems to me that @ least for monitor vm-events VMX is enough. > Yes. OTOH I don't think you can find any CPUs on the market today that support VMX but have no EPT so this hasn't really caused any issues for anyone using vm_events, but technically yes VMX is enough for these events. > AFAIK for non-hap case CR3 needs to be trapped unconditionally, yes. > > >> If the former is true, shouldn't we do a check like this in >> vm_event_monitor_get_capabilities instead? >> > > Yes, it should now, this code was just written before > vm_event_monitor_get_capabilities was introduced and we haven't gotten > around converting this check to it. > > > Is there any reason why monitor vm-events in their current state wouldn't > work on non-hap domains? > If they would work, shouldn't we instead simply move the > monitor.write_ctrlreg_enabled part out of the if ( paging_mode_hap(...) ) ? > Yeap, that sounds like the right place to have that check. Tamas
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