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Re: [Qemu-devel] [PATCH v4 2/5] memory: Add IOMMU_ATTR_HW_NESTED_PAGING
From: |
Auger Eric |
Subject: |
Re: [Qemu-devel] [PATCH v4 2/5] memory: Add IOMMU_ATTR_HW_NESTED_PAGING IOMMU memory region attribute |
Date: |
Wed, 28 Aug 2019 08:24:47 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
Hi Peter,
On 8/27/19 6:19 PM, Peter Maydell wrote:
> On Thu, 22 Aug 2019 at 18:24, Eric Auger <address@hidden> wrote:
>>
>> We introduce a new IOMMU Memory Region attribute,
>> IOMMU_ATTR_HW_NESTED_PAGING that tells whether the virtual
>> IOMMU relies on physical IOMMU HW nested paging capability
>> when protecting host assigned devices.
>
> I'm still not really happy with the name of this attribute.
> "IOMMU_ATTR_HW_NESTED_PAGING" sounds like it ought to mean
> "true if this IOMMU supports/is using hardware nested paging". What
> your commit message suggests it means is "true if this IOMMU
> *needs* hardware nested paging", but there's no NEEDS in the
> attribute name.
OK I will respin and add "_NEED_".
Thanks
Eric
>
>> Current Intel virtual IOMMU device supports "Caching
>> Mode" and does not require 2 stages at physical level to be
>> integrated with VFIO. However SMMUv3 does not implement such
>> "caching mode" and requires to use HW nested paging.
>>
>> As such SMMUv3 is the first IOMMU device to advertise this
>> attribute.
>>
>> Signed-off-by: Eric Auger <address@hidden>
>
> The code changes look good to me though.
>
> thanks
> -- PMM
>
- [Qemu-devel] [PATCH v4 0/5] ARM SMMUv3: Fix spurious notification errors and fail with VFIO, Eric Auger, 2019/08/22
- [Qemu-devel] [PATCH v4 1/5] memory: Remove unused memory_region_iommu_replay_all(), Eric Auger, 2019/08/22
- [Qemu-devel] [PATCH v4 2/5] memory: Add IOMMU_ATTR_HW_NESTED_PAGING IOMMU memory region attribute, Eric Auger, 2019/08/22
- [Qemu-devel] [PATCH v4 3/5] hw/vfio/common: Fail on VFIO/HW nested paging detection, Eric Auger, 2019/08/22
- [Qemu-devel] [PATCH v4 4/5] hw/arm/smmuv3: Log a guest error when decoding an invalid STE, Eric Auger, 2019/08/22
- [Qemu-devel] [PATCH v4 5/5] hw/arm/smmuv3: Remove spurious error messages on IOVA invalidations, Eric Auger, 2019/08/22
- Re: [Qemu-devel] [PATCH v4 0/5] ARM SMMUv3: Fix spurious notification errors and fail with VFIO, Peter Maydell, 2019/08/27