From: David Hildenbrand <david@redhat.com>
To: Logan Gunthorpe <logang@deltatee.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, platform-driver-x86@vger.kernel.org,
linux-mm@kvack.org, Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 5/6] mm, memory_hotplug: Provide argument for the pgprot_t in arch_add_memory()
Date: Mon, 9 Dec 2019 20:23:33 +0100 [thread overview]
Message-ID: <ce50d9da-c60e-05a1-a86b-3bb3629de502@redhat.com> (raw)
In-Reply-To: <20191209191346.5197-6-logang@deltatee.com>
On 09.12.19 20:13, Logan Gunthorpe wrote:
> devm_memremap_pages() is currently used by the PCI P2PDMA code to create
> struct page mappings for IO memory. At present, these mappings are created
> with PAGE_KERNEL which implies setting the PAT bits to be WB. However, on
> x86, an mtrr register will typically override this and force the cache
> type to be UC-. In the case firmware doesn't set this register it is
> effectively WB and will typically result in a machine check exception
> when it's accessed.
>
> Other arches are not currently likely to function correctly seeing they
> don't have any MTRR registers to fall back on.
>
> To solve this, add an argument to arch_add_memory() to explicitly
> set the pgprot value to a specific value.
>
> Of the arches that support MEMORY_HOTPLUG: x86_64, s390 and arm64 is a
> simple change to pass the pgprot_t down to their respective functions
> which set up the page tables. For x86_32, set the page tables explicitly
> using _set_memory_prot() (seeing they are already mapped). For sh, reject
> anything but PAGE_KERNEL settings -- this should be fine, for now, seeing
> sh doesn't support ZONE_DEVICE anyway.
>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
> arch/arm64/mm/mmu.c | 4 ++--
> arch/ia64/mm/init.c | 5 ++++-
> arch/powerpc/mm/mem.c | 4 ++--
> arch/s390/mm/init.c | 4 ++--
> arch/sh/mm/init.c | 5 ++++-
> arch/x86/mm/init_32.c | 7 ++++++-
> arch/x86/mm/init_64.c | 4 ++--
> include/linux/memory_hotplug.h | 2 +-
> mm/memory_hotplug.c | 2 +-
> mm/memremap.c | 2 +-
> 10 files changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 60c929f3683b..48b65272df15 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -1050,7 +1050,7 @@ int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
> }
>
> #ifdef CONFIG_MEMORY_HOTPLUG
> -int arch_add_memory(int nid, u64 start, u64 size,
> +int arch_add_memory(int nid, u64 start, u64 size, pgprot_t prot,
> struct mhp_restrictions *restrictions)
Can we fiddle that into "struct mhp_restrictions" instead?
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-12-09 19:23 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 19:13 [PATCH 0/6] Allow setting caching mode in arch_add_memory() for P2PDMA Logan Gunthorpe
2019-12-09 19:13 ` [PATCH 1/6] x86/mm: Thread pgprot_t through init_memory_mapping() Logan Gunthorpe
2019-12-09 19:13 ` [PATCH 2/6] x86/mm: Introduce _set_memory_prot() Logan Gunthorpe
2019-12-09 19:13 ` [PATCH 3/6] powerpc/mm: Thread pgprot_t through create_section_mapping() Logan Gunthorpe
2019-12-09 19:13 ` [PATCH 4/6] s390/mm: Thread pgprot_t through vmem_add_mapping() Logan Gunthorpe
2019-12-09 19:13 ` [PATCH 5/6] mm, memory_hotplug: Provide argument for the pgprot_t in arch_add_memory() Logan Gunthorpe
2019-12-09 19:23 ` David Hildenbrand [this message]
2019-12-09 20:24 ` Logan Gunthorpe
2019-12-09 20:41 ` Michal Hocko
2019-12-09 21:00 ` Dan Williams
2019-12-09 21:27 ` Logan Gunthorpe
2019-12-09 21:24 ` Logan Gunthorpe
2019-12-10 9:56 ` Michal Hocko
2019-12-09 20:43 ` Dan Williams
2019-12-09 20:52 ` David Hildenbrand
2019-12-10 10:04 ` Michal Hocko
2019-12-10 10:09 ` David Hildenbrand
2019-12-10 10:34 ` Michal Hocko
2019-12-10 11:25 ` David Hildenbrand
2019-12-10 23:52 ` Logan Gunthorpe
2019-12-11 8:37 ` Michal Hocko
2019-12-09 19:13 ` [PATCH 6/6] mm/memremap: Set caching mode for PCI P2PDMA memory to WC Logan Gunthorpe
2019-12-09 20:43 ` [PATCH 0/6] Allow setting caching mode in arch_add_memory() for P2PDMA Christoph Hellwig
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=ce50d9da-c60e-05a1-a86b-3bb3629de502@redhat.com \
--to=david@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=benh@kernel.crashing.org \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=hch@lst.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=logang@deltatee.com \
--cc=luto@kernel.org \
--cc=mhocko@suse.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=platform-driver-x86@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=will@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).