From: Greg KH <greg@kroah.com>
To: Jianxiong Gao <jxgao@google.com>
Cc: stable@vger.kernel.org
Subject: Re: [PATCH v5.10 0/8] preserve DMA offsets when using swiotlb
Date: Fri, 23 Apr 2021 17:14:18 +0200 [thread overview]
Message-ID: <YILkSsR4ejv5CraF@kroah.com> (raw)
In-Reply-To: <CAMGD6P1OEhOXfFV5JpPfTjWPhjjr8KCGTEhVzB74zpnmdLb4sw@mail.gmail.com>
On Tue, Apr 20, 2021 at 04:38:13PM -0700, Jianxiong Gao wrote:
> On Wed, Apr 7, 2021 at 5:51 AM Greg KH <greg@kroah.com> wrote:
> >
> > On Mon, Apr 05, 2021 at 09:02:22PM +0000, Jianxiong Gao wrote:
> > > Hi all,
> > >
> > > This series of backports fixes the SWIOTLB library to maintain the
> > > page offset when mapping a DMA address. The bug that motivated this
> > > patch series manifested when running a 5.4 kernel as a SEV guest with
> > > an NVMe device. However, any device that infers information from the
> > > page offset and is accessed through the SWIOTLB will benefit from this
> > > bug fix.
> >
> > But this is 5.10, not 5.4, why mention 5.4 here?
> Oops. The cover letter shouldn't mention the kernel version. The bug
> is present in both 5.4 and 5.10. Sorry for the confusion.>
> > And you are backporting a 5.12-rc feature to 5.10, what happened to
> > 5.11?
> No. The goal is to backport a bug fix to the LTS releases.
> > Why not just use 5.12 to get this new feature instead of using an older
> > kernel? It's not like this has ever worked before, right?
> >
> It's true, that a new feature (SEV virtualization) is what motivated
> the bug fix. However, I still think this makes sense to backport to
> the LTS releases because it does fix a pre-existing bug that may be
> impacting pre-existing setups.
How? Anything that installed 5.10 when it was released never had this
working, they had to move to 5.12 to get that to work.
> In particular, while working on these patches, I got the following feedback:
> "There are plenty of other hardware designs that rely on dma mapping
> not adding offsets that did not exist, e.g. ahci and various RDMA
> NICs."
I do not understand that statement, how does that pertain to this patch
set?
confused,
greg k-h
next prev parent reply other threads:[~2021-04-23 15:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 21:02 [PATCH v5.10 0/8] preserve DMA offsets when using swiotlb Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 1/8] driver core: add a min_align_mask field to struct device_dma_parameters Jianxiong Gao
2021-04-07 12:50 ` Greg KH
2021-04-05 21:02 ` [PATCH v5.10 2/8] swiotlb: factor out an io_tlb_offset helper Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 3/8] swiotlb: factor out a nr_slots helper Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 4/8] swiotlb: clean up swiotlb_tbl_unmap_single Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 5/8] swiotlb: refactor swiotlb_tbl_map_single Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 6/8] swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 7/8] swiotlb: respect min_align_mask Jianxiong Gao
2021-04-05 21:02 ` [PATCH v5.10 8/8] nvme-pci: set min_align_mask Jianxiong Gao
2021-04-07 12:51 ` [PATCH v5.10 0/8] preserve DMA offsets when using swiotlb Greg KH
2021-04-20 23:38 ` Jianxiong Gao
2021-04-23 15:14 ` Greg KH [this message]
2021-04-23 17:28 ` Jianxiong Gao
2021-04-23 22:10 ` Jianxiong Gao
2021-04-23 22:33 ` Marc Orr
2021-04-24 14:43 ` Greg KH
2021-04-26 18:00 ` Jianxiong Gao
2021-04-28 16:18 ` Sasha Levin
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=YILkSsR4ejv5CraF@kroah.com \
--to=greg@kroah.com \
--cc=jxgao@google.com \
--cc=stable@vger.kernel.org \
/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).