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Re: [Xen-devel] Ping: [PATCH v2] x86: don't allow clearing of TF_kernel_mode for other than 64-bit PV
- To: Jan Beulich <JBeulich@xxxxxxxx>
- From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
- Date: Fri, 5 Apr 2019 14:03:40 +0100
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- Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Tim Deegan <tim@xxxxxxx>
- Delivery-date: Fri, 05 Apr 2019 13:05:22 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Openpgp: preference=signencrypt
On 05/04/2019 09:12, Jan Beulich wrote:
>>>> On 19.03.19 at 18:01, <george.dunlap@xxxxxxxxxx> wrote:
>> On 3/11/19 4:37 PM, Jan Beulich wrote:
>>> The flag is really only meant for those, both HVM and 32-bit PV tell
>>> kernel from user mode based on CPL/RPL. Remove the all-question-marks
>>> comment and let's be on the safe side here and also suppress clearing
>>> for 32-bit PV (this isn't a fast path after all).
>>>
>>> Remove no longer necessary is_pv_32bit_*() from sh_update_cr3() and
>>> sh_walk_guest_tables(). Note that shadow_one_bit_disable() already
>>> assumes the new behavior.
>>>
>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>> Acked-by: George Dunlap <george.dunlap@xxxxxxxxxx>
> While I intend to take George's ack as being sufficient to cover
> the shadow side, may I please ask for an ack or otherwise for
> the non-mm part of the change? I know you've not been in full
> agreement with the change, but iirc I've never heard back on a
> subsequent reply of mine. And I further think that with the now
> (v2) even more obvious dependency of the shadow code on
> this behavior, the change should really be taken as is.
Also, I've just managed to invalidate my own objection to this change on
the basis that it will break migration.
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
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