From: Tianyu Lan <ltykernel@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
x86@kernel.org, hpa@zytor.com, arnd@arndb.de,
dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, akpm@linux-foundation.org,
kirill.shutemov@linux.intel.com, rppt@kernel.org,
hannes@cmpxchg.org, cai@lca.pw, krish.sadhukhan@oracle.com,
saravanand@fb.com, Tianyu.Lan@microsoft.com,
konrad.wilk@oracle.com, m.szyprowski@samsung.com,
robin.murphy@arm.com, boris.ostrovsky@oracle.com,
jgross@suse.com, sstabellini@kernel.org, joro@8bytes.org,
will@kernel.org, xen-devel@lists.xenproject.org,
davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com,
martin.petersen@oracle.com, iommu@lists.linux-foundation.org,
linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-kernel@vger.kernel.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: [RFC PATCH V3 10/11] HV/Netvsc: Add Isolation VM support for netvsc driver
Date: Mon, 14 Jun 2021 22:04:06 +0800 [thread overview]
Message-ID: <e10c2696-23c3-befe-4f4d-25e18918132f@gmail.com> (raw)
In-Reply-To: <20210614070903.GA29976@lst.de>
On 6/14/2021 3:09 PM, Christoph Hellwig wrote:
> On Mon, Jun 07, 2021 at 11:21:20PM +0800, Tianyu Lan wrote:
>>> dma_map_single can only be used on page baked memory, and if this is
>>> using page backed memory you wouldn't need to do thee phys_to_virt
>>> tricks. Can someone explain the mess here in more detail?
>>
>> Sorry. Could you elaborate the issue? These pages in the pb array are not
>> allocated by DMA API and using dma_map_single() here is to map these pages'
>> address to bounce buffer physical address.
>
> dma_map_single just calls dma_map_page using virt_to_page. So this
> can't work on addresses not in the kernel linear mapping.
>
The pages in the hv_page_buffer array here are in the kernel linear
mapping. The packet sent to host will contain an array which contains
transaction data. In the isolation VM, data in the these pages needs to
be copied to bounce buffer and so call dma_map_single() here to map
these data pages with bounce buffer. The vmbus has ring buffer where the
send/receive packets are copied to/from. The ring buffer has been
remapped to the extra space above shared gpa boundary/vTom during
probing Netvsc driver and so not call dma map function for vmbus ring
buffer.
next prev parent reply other threads:[~2021-06-14 14:04 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-30 15:06 [RFC PATCH V3 00/11] x86/Hyper-V: Add Hyper-V Isolation VM support Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 01/11] x86/HV: Initialize GHCB page in Isolation VM Tianyu Lan
2021-06-07 6:41 ` Christoph Hellwig
2021-06-07 8:14 ` Tianyu Lan
2021-06-09 12:38 ` Joerg Roedel
2021-06-10 14:13 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 02/11] x86/HV: Initialize shared memory boundary in the " Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 03/11] x86/Hyper-V: Add new hvcall guest address host visibility support Tianyu Lan
2021-05-30 18:25 ` Borislav Petkov
2021-05-31 4:08 ` Tianyu Lan
2021-06-10 9:47 ` Vitaly Kuznetsov
2021-06-10 14:18 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 04/11] HV: Add Write/Read MSR registers via ghcb Tianyu Lan
2021-06-09 12:46 ` Joerg Roedel
2021-06-10 14:15 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 05/11] HV: Add ghcb hvcall support for SNP VM Tianyu Lan
2021-06-09 12:49 ` Joerg Roedel
2021-05-30 15:06 ` [RFC PATCH V3 06/11] HV/Vmbus: Add SNP support for VMbus channel initiate message Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 07/11] HV/Vmbus: Initialize VMbus ring buffer for Isolation VM Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 08/11] swiotlb: Add bounce buffer remap address setting function Tianyu Lan
2021-06-07 6:43 ` Christoph Hellwig
2021-06-07 14:56 ` Tianyu Lan
2021-06-10 14:25 ` Tianyu Lan
2021-06-14 7:12 ` Christoph Hellwig
2021-06-14 13:29 ` Tom Lendacky
2021-06-14 13:37 ` Tianyu Lan
2021-06-14 13:42 ` Tianyu Lan
2021-06-14 13:49 ` Robin Murphy
2021-06-14 15:32 ` Christoph Hellwig
2021-06-15 15:24 ` Tianyu Lan
2021-07-12 9:40 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 09/11] HV/IOMMU: Enable swiotlb bounce buffer for Isolation VM Tianyu Lan
2021-06-02 1:16 ` Boris Ostrovsky
2021-06-02 15:01 ` Tianyu Lan
2021-06-02 16:02 ` Boris Ostrovsky
2021-06-03 15:37 ` Tianyu Lan
2021-06-03 17:04 ` Boris Ostrovsky
2021-06-07 6:44 ` Christoph Hellwig
2021-05-30 15:06 ` [RFC PATCH V3 10/11] HV/Netvsc: Add Isolation VM support for netvsc driver Tianyu Lan
2021-06-07 6:50 ` Christoph Hellwig
2021-06-07 15:21 ` Tianyu Lan
2021-06-14 7:09 ` Christoph Hellwig
2021-06-14 14:04 ` Tianyu Lan [this message]
2021-06-14 15:33 ` Christoph Hellwig
2021-06-15 14:31 ` Tianyu Lan
2021-06-10 9:52 ` Vitaly Kuznetsov
2021-05-30 15:06 ` [RFC PATCH V3 11/11] HV/Storvsc: Add Isolation VM support for storvsc driver Tianyu Lan
2021-06-07 6:46 ` Christoph Hellwig
2021-06-07 14:59 ` Tianyu Lan
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