Re: [PATCH 1/1] iommu/amd: Preserve default DTE fields when updating Host Page Table Root
From: Vasant Hegde
Date: Fri Feb 28 2025 - 04:55:27 EST
On 2/26/2025 9:49 PM, Alejandro Jimenez wrote:
>
>
> On 1/7/25 13:01, Jason Gunthorpe wrote:
>> On Tue, Jan 07, 2025 at 05:45:38PM +0530, Vasant Hegde wrote:
>>>> @@ -2052,12 +2052,12 @@ static void set_dte_entry(struct amd_iommu *iommu,
>>>> make_clear_dte(dev_data, dte, &new);
>>>
>>> This fix is fine. But with all changes we have done in this code does, do we
>>> really need make_clear_dte()?
>>
>>> How about removing `make_clear_dte()` and moving DTE_FLAG_V to
>>> write_dte_lower128() ?
>>
>> The V flag should just be set by the functions building the DTE,
>> write_dte_lower() should accept a fully formed dte as a matter of
>> layering.
>>
>> I'm hopefull Suravee will come with something like this:
>>
>> https://lore.kernel.org/linux-iommu/20241016142237.GP3559746@xxxxxxxxxx/
>>
>
> Suravee did say he would implement the suggestions above in the series for
> nested translation support, but that might take a while considering where
> we are in the cycle. Given that this fix is straightforward and has been
> reviewed by Dheeraj, are there any concerns with merging it in its current
> form?
Ack. I think its fine to pull current patch for now.
Reviewed-by: Vasant Hegde <vasant.hegde@xxxxxxx>
-Vasant