On 06/23/2016 12:34 AM, Bandan Das wrote:
Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> writes:
On 06/21/2016 11:12 AM, Bandan Das wrote:
I spoke to Paolo about this a while back and thought to post this as
RFC while I am thinking of adding some unit tests.
Background: ESX refuses to run as L1 if support for EPT execute only isn't
found. I am not really sure if it uses it for anything since just advertising
the bits seems to work but adding the necessary plumbing seemed like a good idea.
Xiao, I took the liberty of adding you based on "git blame" :)
Thank you, Bandan! I really hope all mmu related patches can be CCed to me
in case if i am too busy to watch patches in kvm mail list. :)
We all try but it's easy to miss interested people in the cc list :)
Some points are missed in this patchset:
1) You also need to tech is_present_gpte() about this fact.
If I understood right, this isn't needed anymore since a check
for rsvd bits follows and is_present_gpte already does pte & 7.
is_present_gpte() and FNAME(is_present_gpte) are different paths.
Currently, it is safe as is_present_gpte() is only used for 32 bit
guests, however, making it consistent can avoid potential bugs
in the further.
2) update_permission_bitmask() need to be fixed as it always expects
that read-access is available (actually, read-access is equal with
user-access if ept is shadowed).
Do you mean this part of update_permission_bitmask() ?
...
} else
/* Not really needed: no U/S accesses on ept */
u = 1;
Yes.
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