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: Tue, 15 Jun 2021 22:31:31 +0800 [thread overview]
Message-ID: <7d86307f-83ff-03ad-c6e9-87b455c559b8@gmail.com> (raw)
In-Reply-To: <20210614153339.GB1741@lst.de>
On 6/14/2021 11:33 PM, Christoph Hellwig wrote:
> On Mon, Jun 14, 2021 at 10:04:06PM +0800, Tianyu Lan wrote:
>> 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.
>
> So why do we have all that PFN magic instead of using struct page or
> the usual kernel I/O buffers that contain a page pointer?
>
These PFNs originally is part of Hyper-V protocol data and will be sent
to host. Host accepts these GFN and copy data from/to guest memory. The
translation from va to pa is done by caller that populates the
hv_page_buffer array. I will try calling dma map function before
populating struct hv_page_buffer and this can avoid redundant
translation between PA and VA.
next prev parent reply other threads:[~2021-06-15 14:32 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
2021-06-14 15:33 ` Christoph Hellwig
2021-06-15 14:31 ` Tianyu Lan [this message]
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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