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From: Christoph Hellwig <hch@lst.de>
To: Tianyu Lan <ltykernel@gmail.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
	sthemmin@microsoft.com, wei.liu@kernel.org, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
	arnd@arndb.de, akpm@linux-foundation.org,
	gregkh@linuxfoundation.org, konrad.wilk@oracle.com, hch@lst.de,
	m.szyprowski@samsung.com, robin.murphy@arm.com, joro@8bytes.org,
	will@kernel.org, davem@davemloft.net, kuba@kernel.org,
	jejb@linux.ibm.com, martin.petersen@oracle.com,
	Tianyu Lan <Tianyu.Lan@microsoft.com>,
	iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org,
	linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux-scsi@vger.kernel.org,
	netdev@vger.kernel.org, vkuznets@redhat.com,
	thomas.lendacky@amd.com, brijesh.singh@amd.com,
	sunilmut@microsoft.com
Subject: Re: [Resend RFC PATCH V2 10/12] HV/IOMMU: Add Hyper-V dma ops support
Date: Wed, 14 Apr 2021 17:47:29 +0200
Message-ID: <20210414154729.GD32045@lst.de> (raw)
In-Reply-To: <20210414144945.3460554-11-ltykernel@gmail.com>

> +static dma_addr_t hyperv_map_page(struct device *dev, struct page *page,
> +				  unsigned long offset, size_t size,
> +				  enum dma_data_direction dir,
> +				  unsigned long attrs)
> +{
> +	phys_addr_t map, phys = (page_to_pfn(page) << PAGE_SHIFT) + offset;
> +
> +	if (!hv_is_isolation_supported())
> +		return phys;
> +
> +	map = swiotlb_tbl_map_single(dev, phys, size, HV_HYP_PAGE_SIZE, dir,
> +				     attrs);
> +	if (map == (phys_addr_t)DMA_MAPPING_ERROR)
> +		return DMA_MAPPING_ERROR;
> +
> +	return map;
> +}

This largerly duplicates what dma-direct + swiotlb does.  Please use
force_dma_unencrypted to force bounce buffering and just use the generic
code.

> +	if (hv_isolation_type_snp()) {
> +		ret = hv_set_mem_host_visibility(
> +				phys_to_virt(hyperv_io_tlb_start),
> +				hyperv_io_tlb_size,
> +				VMBUS_PAGE_VISIBLE_READ_WRITE);
> +		if (ret)
> +			panic("%s: Fail to mark Hyper-v swiotlb buffer visible to host. err=%d\n",
> +			      __func__, ret);
> +
> +		hyperv_io_tlb_remap = ioremap_cache(hyperv_io_tlb_start
> +					    + ms_hyperv.shared_gpa_boundary,
> +						    hyperv_io_tlb_size);
> +		if (!hyperv_io_tlb_remap)
> +			panic("%s: Fail to remap io tlb.\n", __func__);
> +
> +		memset(hyperv_io_tlb_remap, 0x00, hyperv_io_tlb_size);
> +		swiotlb_set_bounce_remap(hyperv_io_tlb_remap);

And this really needs to go into a common hook where we currently just
call set_memory_decrypted so that all the different schemes for these
trusted VMs (we have about half a dozen now) can share code rather than
reinventing it.

  reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-14 14:49 [Resend RFC PATCH V2 00/12] x86/Hyper-V: Add Hyper-V Isolation VM support Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 01/12] x86/HV: Initialize GHCB page in Isolation VM Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 02/12] x86/HV: Initialize shared memory boundary " Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 03/12] x86/Hyper-V: Add new hvcall guest address host visibility support Tianyu Lan
2021-04-14 15:40   ` Christoph Hellwig
2021-04-15  8:13     ` Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 04/12] HV: Add Write/Read MSR registers via ghcb Tianyu Lan
2021-04-14 15:41   ` Christoph Hellwig
2021-04-15  8:19     ` Tianyu Lan
2021-04-15 18:11   ` Konrad Rzeszutek Wilk
2021-04-14 14:49 ` [Resend RFC PATCH V2 05/12] HV: Add ghcb hvcall support for SNP VM Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 06/12] HV/Vmbus: Add SNP support for VMbus channel initiate message Tianyu Lan
2021-04-15 18:52   ` Konrad Rzeszutek Wilk
2021-04-14 14:49 ` [Resend RFC PATCH V2 07/12] HV/Vmbus: Initialize VMbus ring buffer for Isolation VM Tianyu Lan
2021-04-15 20:24   ` Konrad Rzeszutek Wilk
2021-04-19  6:36     ` Christoph Hellwig
2021-04-14 14:49 ` [Resend RFC PATCH V2 08/12] UIO/Hyper-V: Not load UIO HV driver in the isolation VM Tianyu Lan
2021-04-14 15:42   ` Christoph Hellwig
2021-04-14 15:45   ` Greg KH
2021-04-14 16:17     ` Stephen Hemminger
2021-04-15 12:54       ` Tianyu Lan
2021-04-15 13:09     ` Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 09/12] swiotlb: Add bounce buffer remap address setting function Tianyu Lan
2021-04-15 20:28   ` Konrad Rzeszutek Wilk
2021-04-14 14:49 ` [Resend RFC PATCH V2 10/12] HV/IOMMU: Add Hyper-V dma ops support Tianyu Lan
2021-04-14 15:47   ` Christoph Hellwig [this message]
2021-05-12 16:01     ` Tianyu Lan
2021-05-12 17:29       ` Robin Murphy
2021-05-13  3:19       ` Lu Baolu
2021-04-14 14:49 ` [Resend RFC PATCH V2 11/12] HV/Netvsc: Add Isolation VM support for netvsc driver Tianyu Lan
2021-04-14 15:50   ` Christoph Hellwig
2021-04-15  8:39     ` Tianyu Lan
2021-04-14 14:49 ` [Resend RFC PATCH V2 12/12] HV/Storvsc: Add Isolation VM support for storvsc driver Tianyu Lan
2021-04-14 15:51   ` Christoph Hellwig

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