RE: [PATCH v2 16/17] intel_iommu: Introduce a property to control FS1GP cap bit setting

[Duan, Zhenzhong]

>-----Original Message-----
>From: Liu, Yi L <yi.l.liu@intel.com>
>Subject: Re: [PATCH v2 16/17] intel_iommu: Introduce a property to control
>FS1GP cap bit setting
>
>On 2024/8/5 14:27, Zhenzhong Duan wrote:
>> When host IOMMU doesn't support FS1GP but vIOMMU does, host
>IOMMU
>> can't translate stage-1 page table from guest correctly.
>
>this series is for emulated devices, so the above statement does not
>belong to this series. Is there any other reason to have this option?

Good catch, will remove this comment.
In fact, this patch is mainly for passthrough device where host IOMMU doesn't 
support fs1gp.

>
>> Add a property x-cap-fs1gp for user to turn FS1GP off so that
>> nested page table on host side works.
>
>I guess you would need to sync the FS1GP cap with host before reporting it
>in vIOMMU when comes to support passthrough devices.

Yes, we already have this check, see 
https://github.com/yiliu1765/qemu/commit/b7ac7ce3a2e21eb1b3172743ee6f73e80fe67b3a

Thanks
Zhenzhong