From: Jason Wang <jasowang@redhat.com>
To: Xie Yongji <xieyongji@bytedance.com>,
mst@redhat.com, stefanha@redhat.com, sgarzare@redhat.com,
parav@nvidia.com, hch@infradead.org,
christian.brauner@canonical.com, rdunlap@infradead.org,
willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk,
bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com,
dan.carpenter@oracle.com
Cc: linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v6 08/10] vduse: Implement an MMU-based IOMMU driver
Date: Thu, 8 Apr 2021 11:25:49 +0800 [thread overview]
Message-ID: <30862242-293b-f42f-d8ce-2c31a52e3697@redhat.com> (raw)
In-Reply-To: <20210331080519.172-9-xieyongji@bytedance.com>
在 2021/3/31 下午4:05, Xie Yongji 写道:
> This implements an MMU-based IOMMU driver to support mapping
> kernel dma buffer into userspace. The basic idea behind it is
> treating MMU (VA->PA) as IOMMU (IOVA->PA). The driver will set
> up MMU mapping instead of IOMMU mapping for the DMA transfer so
> that the userspace process is able to use its virtual address to
> access the dma buffer in kernel.
>
> And to avoid security issue, a bounce-buffering mechanism is
> introduced to prevent userspace accessing the original buffer
> directly.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
With some nits:
> ---
> drivers/vdpa/vdpa_user/iova_domain.c | 521 +++++++++++++++++++++++++++++++++++
> drivers/vdpa/vdpa_user/iova_domain.h | 70 +++++
> 2 files changed, 591 insertions(+)
> create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
> create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h
[...]
> +static void vduse_domain_bounce(struct vduse_iova_domain *domain,
> + dma_addr_t iova, size_t size,
> + enum dma_data_direction dir)
> +{
> + struct vduse_bounce_map *map;
> + unsigned int offset;
> + void *addr;
> + size_t sz;
> +
> + while (size) {
> + map = &domain->bounce_maps[iova >> PAGE_SHIFT];
> + offset = offset_in_page(iova);
> + sz = min_t(size_t, PAGE_SIZE - offset, size);
> +
> + if (WARN_ON(!map->bounce_page ||
> + map->orig_phys == INVALID_PHYS_ADDR))
> + return;
> +
> + addr = page_address(map->bounce_page) + offset;
> + do_bounce(map->orig_phys + offset, addr, sz, dir);
> + size -= sz;
> + iova += sz;
> + }
> +}
> +
> +static struct page *
> +vduse_domain_get_mapping_page(struct vduse_iova_domain *domain, u64 iova)
It's better to rename this as "vduse_domain_get_coherent_page?".
> +{
> + u64 start = iova & PAGE_MASK;
> + u64 last = start + PAGE_SIZE - 1;
> + struct vhost_iotlb_map *map;
> + struct page *page = NULL;
> +
> + spin_lock(&domain->iotlb_lock);
> + map = vhost_iotlb_itree_first(domain->iotlb, start, last);
> + if (!map)
> + goto out;
> +
> + page = pfn_to_page((map->addr + iova - map->start) >> PAGE_SHIFT);
> + get_page(page);
> +out:
> + spin_unlock(&domain->iotlb_lock);
> +
> + return page;
> +}
> +
[...]
> +
> +static dma_addr_t
> +vduse_domain_alloc_iova(struct iova_domain *iovad,
> + unsigned long size, unsigned long limit)
> +{
> + unsigned long shift = iova_shift(iovad);
> + unsigned long iova_len = iova_align(iovad, size) >> shift;
> + unsigned long iova_pfn;
> +
> + if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
> + iova_len = roundup_pow_of_two(iova_len);
Let's add a comment as what has been done in dma-iommu.c?
(In the future, it looks to me it's better to move them to
alloc_iova_fast()).
Thanks
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-04-08 3:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210331080519.172-1-xieyongji@bytedance.com>
[not found] ` <20210331080519.172-2-xieyongji@bytedance.com>
[not found] ` <20210331091545.lr572rwpyvrnji3w@wittgenstein>
2021-03-31 9:26 ` [PATCH v6 01/10] file: Export receive_fd() to modules Dan Carpenter
[not found] ` <20210331080519.172-8-xieyongji@bytedance.com>
2021-04-08 2:36 ` [PATCH v6 07/10] vdpa: Support transferring virtual addressing during DMA mapping Jason Wang
[not found] ` <20210331080519.172-9-xieyongji@bytedance.com>
2021-04-08 3:25 ` Jason Wang [this message]
[not found] ` <20210331080519.172-10-xieyongji@bytedance.com>
2021-04-08 6:57 ` [PATCH v6 09/10] vduse: Introduce VDUSE - vDPA Device in Userspace Jason Wang
[not found] ` <CACycT3v_KFQXoxRbEj8c0Ve6iKn9RbibtBDgBFs=rf0ZOmTBBQ@mail.gmail.com>
2021-04-09 5:36 ` Jason Wang
[not found] ` <CACycT3vwATp4+Ao0fjuyeeLQN+xHH=dXF+JUyuitkn4k8hELnA@mail.gmail.com>
2021-04-12 7:16 ` Jason Wang
[not found] ` <CACycT3vxO21Yt6+px2c2Q8DONNUNehdo2Vez_RKQCKe76CM2TA@mail.gmail.com>
2021-04-12 9:37 ` Jason Wang
[not found] ` <CACycT3vbDhUKM0OX-zo02go09gh2+EEdyZ_YQuz8PXzo3EngXw@mail.gmail.com>
2021-04-13 3:35 ` Jason Wang
[not found] ` <CACycT3tHxtfgQhQgv0VyF_U523qASEv1Ydc4XuX43MFRzGVbfw@mail.gmail.com>
2021-04-14 8:18 ` Jason Wang
2021-04-16 3:24 ` Jason Wang
[not found] ` <20210331080519.172-4-xieyongji@bytedance.com>
2021-04-09 16:15 ` [PATCH v6 03/10] vhost-vdpa: protect concurrent access to vhost device iotlb Michael S. Tsirkin
[not found] ` <CACycT3tPWwpGBNEqiL4NPrwGZhmUtAVHUZMOdbSHzjhN-ytg_A@mail.gmail.com>
2021-04-11 20:48 ` Michael S. Tsirkin
[not found] ` <CACycT3v5Z8s9_pL79m0FY5jxx3fTRHHbtARfg0On3xTnNCOdkg@mail.gmail.com>
2021-04-12 9:00 ` Michael S. Tsirkin
2021-04-14 7:34 ` [PATCH v6 00/10] Introduce VDUSE - vDPA Device in Userspace Michael S. Tsirkin
2021-04-14 7:49 ` Jason Wang
[not found] ` <20210331080519.172-11-xieyongji@bytedance.com>
2021-04-08 7:18 ` [PATCH v6 10/10] Documentation: Add documentation for VDUSE Jason Wang
2021-04-14 14:14 ` Stefan Hajnoczi
[not found] ` <CACycT3uNR+nZY5gY0UhPkeOyi7Za6XkX4b=hasuDcgqdc7fqfg@mail.gmail.com>
2021-04-15 7:19 ` Stefan Hajnoczi
2021-04-15 8:36 ` Jason Wang
2021-04-15 9:04 ` Jason Wang
[not found] ` <CACycT3tL7URz3n-KhMAwYH+Sn1e1TSyfU+RKcc8jpPDJ7WcZ2w@mail.gmail.com>
2021-04-16 2:20 ` Jason Wang
[not found] ` <CACycT3tyksBYxgbQLFJ-mFCKkaWotucM5_ho_K3q4wMpR0P=gw@mail.gmail.com>
2021-04-16 3:02 ` Jason Wang
2021-04-15 14:38 ` Stefan Hajnoczi
2021-04-16 2:23 ` Jason Wang
[not found] ` <CACycT3u_qAE=D_ezLPU9SpXPMACErmpqpH5pMg0TZAb3CZVGdg@mail.gmail.com>
2021-04-16 5:39 ` Jason Wang
[not found] ` <CACycT3tRN1n_PJm1mu3=s1dK941Pac15cpaysqZZKLR6xKaXSg@mail.gmail.com>
2021-04-15 14:17 ` Re: " Stefan Hajnoczi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=30862242-293b-f42f-d8ce-2c31a52e3697@redhat.com \
--to=jasowang@redhat.com \
--cc=axboe@kernel.dk \
--cc=bcrl@kvack.org \
--cc=christian.brauner@canonical.com \
--cc=corbet@lwn.net \
--cc=dan.carpenter@oracle.com \
--cc=hch@infradead.org \
--cc=kvm@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=mika.penttila@nextfour.com \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=parav@nvidia.com \
--cc=rdunlap@infradead.org \
--cc=sgarzare@redhat.com \
--cc=stefanha@redhat.com \
--cc=viro@zeniv.linux.org.uk \
--cc=virtualization@lists.linux-foundation.org \
--cc=willy@infradead.org \
--cc=xieyongji@bytedance.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).