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Date:   Mon, 2 Aug 2021 15:20:03 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Tianyu Lan <ltykernel@gmail.com>
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Subject: Re: [PATCH 13/13] HV/Storvsc: Add Isolation VM support for storvsc
 driver
Message-ID: <YQfxA/AYfOqyqNh0@8bytes.org>
References: <20210728145232.285861-1-ltykernel@gmail.com>
 <20210728145232.285861-14-ltykernel@gmail.com>
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On Wed, Jul 28, 2021 at 10:52:28AM -0400, Tianyu Lan wrote:
> In Isolation VM, all shared memory with host needs to mark visible
> to host via hvcall. vmbus_establish_gpadl() has already done it for
> storvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_
> mpb_desc() still need to handle. Use DMA API to map/umap these
> memory during sending/receiving packet and Hyper-V DMA ops callback
> will use swiotlb function to allocate bounce buffer and copy data
> from/to bounce buffer.

I am wondering why you dont't use DMA-API unconditionally? It provides
enough abstraction to do the right thing for isolated and legacy VMs.

Regards,

	Joerg