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Re: [PATCH v2 2/3] x86: detect PIC aliasing on ports other than 0x[2A][01]
- To: Jan Beulich <jbeulich@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Jason Andryuk <jason.andryuk@xxxxxxx>
- Date: Thu, 9 May 2024 12:06:40 -0400
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- Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>
- Delivery-date: Thu, 09 May 2024 16:07:04 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 2023-12-18 09:48, Jan Beulich wrote:
... in order to also deny Dom0 access through the alias ports. Without
this it is only giving the impression of denying access to both PICs.
Unlike for CMOS/RTC, do detection very early, to avoid disturbing normal
operation later on.
Like for CMOS/RTC a fundamental assumption of the probing is that reads
from the probed alias port won't have side effects in case it does not
alias the respective PIC's one.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Code-wise
Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
I appreciate what Jan is trying to achieve. I also share Roger's
concern about reading IO ports since we don't know what is there.
I also don't have a good alternative to suggest...
Regards,
Jason
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