From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org
Cc: Brian J King <bjking1@us.ibm.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Oliver O'Halloran <oohall@gmail.com>,
David Gibson <david@gibson.dropbear.id.au>,
Wen Xiong <wenxiong@us.ibm.com>
Subject: Re: [PATCH kernel] powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent memory
Date: Mon, 6 Apr 2020 23:05:47 +1000 (AEST) [thread overview]
Message-ID: <48wrPp3nXMz9sSJ@ozlabs.org> (raw)
In-Reply-To: <20200331012338.23773-1-aik@ozlabs.ru>
On Tue, 2020-03-31 at 01:23:38 UTC, Alexey Kardashevskiy wrote:
> Unlike normal memory ("memory" compatible type in the FDT),
> the persistent memory ("ibm,pmemory" in the FDT) can be mapped anywhere
> in the guest physical space and it can be used for DMA.
>
> In order to maintain 1:1 mapping via the huge DMA window, we need to
> know the maximum physical address at the time of the window setup.
> So far we've been looking at "memory" nodes but "ibm,pmemory" does not
> have fixed addresses and the persistent memory may be mapped afterwards.
>
> Since the persistent memory is still backed with page structs,
> use MAX_PHYSMEM_BITS as the upper limit.
>
> This effectively disables huge DMA window in LPAR under pHyp if
> persistent memory is present but this is the best we can do.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/54fc3c681ded9437e4548e2501dc1136b23cfa9a
cheers
prev parent reply other threads:[~2020-04-06 13:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-31 1:23 [PATCH kernel] powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent memory Alexey Kardashevskiy
[not found] ` <OFAFE8A91E.912BDABA-ON0025853E.00788BCA-0025853E.0079C2C8@notes.na.collabserv.com>
2020-04-03 8:06 ` Alexey Kardashevskiy
2020-04-03 10:04 ` Vaibhav Jain
2020-04-06 13:05 ` Michael Ellerman [this message]
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=48wrPp3nXMz9sSJ@ozlabs.org \
--to=patch-notifications@ellerman.id.au \
--cc=aik@ozlabs.ru \
--cc=aneesh.kumar@linux.ibm.com \
--cc=bjking1@us.ibm.com \
--cc=david@gibson.dropbear.id.au \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=oohall@gmail.com \
--cc=wenxiong@us.ibm.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).