lkml.org 
[lkml]   [2021]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page
From
Date
On Mon, 2021-09-13 at 17:14 +0200, Paolo Bonzini wrote:
> On 13/09/21 16:55, Dave Hansen wrote:
> > > By "Windows startup" I mean even after guest reboot. Because another
> > > process could sneak in and steal your EPC pages between a close() and an
> > > open(), I'd like to have a way to EREMOVE the pages while keeping them
> > > assigned to the specific vEPC instance, i.e.*without* going through
> > > sgx_vepc_free_page().
> > Oh, so you want fresh EPC state for the guest, but you're concerned that
> > the previous guest might have left them in a bad state. The current
> > method of getting a new vepc instance (which guarantees fresh state) has
> > some other downsides.
> >
> > Can't another process steal pages via sgxd and reclaim at any time?
>
> vEPC pages never call sgx_mark_page_reclaimable, don't they?
>
> > What's the extra concern here about going through a close()/open()
> > cycle? Performance?
>
> Apart from reclaiming, /dev/sgx_vepc might disappear between the first
> open() and subsequent ones.

If /dev/sgx_vepc dissapears, why is it a problem *for the software*, and
not a sysadmin problem?

I think that this is what the whole patch is lacking, why are we talking
about a software problem...

/Jarkko

\
 
 \ /
  Last update: 2021-09-13 23:15    [W:0.139 / U:0.892 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site