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Re: [PATCH v3 1/4] xen/arm/static-shmem: Static-shmem should be direct-mapped for direct-mapped domains
- To: Michal Orzel <michal.orzel@xxxxxxx>
- From: Luca Fancellu <Luca.Fancellu@xxxxxxx>
- Date: Mon, 20 May 2024 12:18:08 +0000
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- Cc: Henry Wang <xin.wang2@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
- Delivery-date: Mon, 20 May 2024 12:18:38 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
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- Thread-topic: [PATCH v3 1/4] xen/arm/static-shmem: Static-shmem should be direct-mapped for direct-mapped domains
> On 20 May 2024, at 12:24, Michal Orzel <michal.orzel@xxxxxxx> wrote:
>
> Hi Henry,
>
> +CC: Luca
>
> On 17/05/2024 05:21, Henry Wang wrote:
>>
>>
>> Currently, users are allowed to map static shared memory in a
>> non-direct-mapped way for direct-mapped domains. This can lead to
>> clashing of guest memory spaces. Also, the current extended region
>> finding logic only removes the host physical addresses of the
>> static shared memory areas for direct-mapped domains, which may be
>> inconsistent with the guest memory map if users map the static
>> shared memory in a non-direct-mapped way. This will lead to incorrect
>> extended region calculation results.
>>
>> To make things easier, add restriction that static shared memory
>> should also be direct-mapped for direct-mapped domains. Check the
>> host physical address to be matched with guest physical address when
>> parsing the device tree. Document this restriction in the doc.
> I'm ok with this restriction.
>
> @Luca, do you have any use case preventing us from making this restriction?
Hi Michal, Henry,
I think it’s sensible, I don’t think we have any use case for direct-mapped
domains using
non direct mapped static shared memory.
Cheers,
Luca
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