Re: [PATCH 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM

To: Tianyu Lan <ltykernel@xxxxxxxxx>
Subject: Re: [PATCH 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM
From: Christoph Hellwig <hch@xxxxxx>
Date: Wed, 17 Nov 2021 11:01:42 +0100
Cc: dave.hansen@xxxxxxxxxxxxxxx, luto@xxxxxxxxxx, peterz@xxxxxxxxxxxxx, tglx@xxxxxxxxxxxxx, mingo@xxxxxxxxxx, bp@xxxxxxxxx, x86@xxxxxxxxxx, hpa@xxxxxxxxx, jgross@xxxxxxxx, sstabellini@xxxxxxxxxx, boris.ostrovsky@xxxxxxxxxx, kys@xxxxxxxxxxxxx, haiyangz@xxxxxxxxxxxxx, sthemmin@xxxxxxxxxxxxx, wei.liu@xxxxxxxxxx, decui@xxxxxxxxxxxxx, joro@xxxxxxxxxx, will@xxxxxxxxxx, davem@xxxxxxxxxxxxx, kuba@xxxxxxxxxx, jejb@xxxxxxxxxxxxx, martin.petersen@xxxxxxxxxx, hch@xxxxxx, m.szyprowski@xxxxxxxxxxx, robin.murphy@xxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxxx, michael.h.kelley@xxxxxxxxxxxxx, Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>, iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx, linux-hyperv@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, linux-scsi@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx, vkuznets@xxxxxxxxxx, brijesh.singh@xxxxxxx, konrad.wilk@xxxxxxxxxx, parri.andrea@xxxxxxxxx, thomas.lendacky@xxxxxxx, dave.hansen@xxxxxxxxx
In-reply-to: <20211116153923.196763-4-ltykernel@gmail.com>
User-agent: Mutt/1.5.17 (2007-11-01)

This doesn't really have much to do with normal DMA mapping,
so why does this direct through the dma ops?

Follow-Ups:
- Re: [PATCH 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM
  - From: Tianyu Lan

References:
- [PATCH 0/5] x86/Hyper-V: Add Hyper-V Isolation VM support(Second part)
  - From: Tianyu Lan
- [PATCH 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM
  - From: Tianyu Lan