From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, Borislav Petkov <bp@alien8.de>,
Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v3 3/7] mm: Add vm_insert_pfn_prot
Date: Tue, 29 Dec 2015 20:12:20 -0800 [thread overview]
Message-ID: <d2938d1eb37be7a5e4f86182db646551f11e45aa.1451446564.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1451446564.git.luto@kernel.org>
In-Reply-To: <cover.1451446564.git.luto@kernel.org>
The x86 vvar vma conntains pages with differing cacheability
flags. x86 currently implements this by manually inserting all the ptes
using (io_)remap_pfn_range when the vma is set up.
x86 wants to move to using .fault with VM_FAULT_NOPAGE to set up the
mappings as needed. The correct API to use to insert a pfn in
.fault is vm_insert_pfn, but vm_insert_pfn can't override the vma's
cache mode, and the HPET page in particular needs to be uncached
despite the fact that the rest of the VMA is cached.
Add vm_insert_pfn_prot to support varying cacheability within the
same non-COW VMA in a more sane manner.
x86 could alternatively use multiple VMAs, but that's messy, would
break CRIU, and would create unnecessary VMAs that would waste
memory.
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
include/linux/mm.h | 2 ++
mm/memory.c | 25 +++++++++++++++++++++++--
2 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 00bad7793788..87ef1d7730ba 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2080,6 +2080,8 @@ int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
+int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, pgprot_t pgprot);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
diff --git a/mm/memory.c b/mm/memory.c
index c387430f06c3..a29f0b90fc56 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1564,8 +1564,29 @@ out:
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn)
{
+ return vm_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_pfn);
+
+/**
+ * vm_insert_pfn_prot - insert single pfn into user vma with specified pgprot
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @pfn: source kernel pfn
+ * @pgprot: pgprot flags for the inserted page
+ *
+ * This is exactly like vm_insert_pfn, except that it allows drivers to
+ * to override pgprot on a per-page basis.
+ *
+ * This only makes sense for IO mappings, and it makes no sense for
+ * cow mappings. In general, using multiple vmas is preferable;
+ * vm_insert_pfn_prot should only be used if using multiple VMAs is
+ * impractical.
+ */
+int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, pgprot_t pgprot)
+{
int ret;
- pgprot_t pgprot = vma->vm_page_prot;
/*
* Technically, architectures with pte_special can avoid all these
* restrictions (same for remap_pfn_range). However we would like
@@ -1587,7 +1608,7 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
return ret;
}
-EXPORT_SYMBOL(vm_insert_pfn);
+EXPORT_SYMBOL(vm_insert_pfn_prot);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn)
--
2.5.0
next prev parent reply other threads:[~2015-12-30 4:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-30 4:12 [PATCH v3 0/7] mm, x86/vdso: Special IO mapping improvements Andy Lutomirski
2015-12-30 4:12 ` [PATCH v3 1/7] x86/vsdo: Fix build on PARAVIRT_CLOCK=y, KVM_GUEST=n Andy Lutomirski
2016-01-05 19:21 ` Borislav Petkov
2016-01-06 9:54 ` [tip:x86/asm] x86/vsdo: Fix build on PARAVIRT_CLOCK=y, KVM_GUEST= n tip-bot for Andy Lutomirski
2015-12-30 4:12 ` [PATCH v3 2/7] mm: Add a vm_special_mapping .fault method Andy Lutomirski
2016-01-12 12:02 ` [tip:x86/asm] mm: Add a vm_special_mapping.fault() method tip-bot for Andy Lutomirski
2015-12-30 4:12 ` Andy Lutomirski [this message]
2016-01-12 12:02 ` [tip:x86/asm] mm: Add vm_insert_pfn_prot() tip-bot for Andy Lutomirski
2015-12-30 4:12 ` [PATCH v3 4/7] x86/vdso: Track each mm's loaded vdso image as well as its base Andy Lutomirski
2016-01-12 12:03 ` [tip:x86/asm] x86/vdso: Track each mm' s loaded vDSO " tip-bot for Andy Lutomirski
2015-12-30 4:12 ` [PATCH v3 5/7] x86,vdso: Use .fault for the vdso text mapping Andy Lutomirski
2016-01-12 12:03 ` [tip:x86/asm] x86/vdso: Use .fault for the vDSO " tip-bot for Andy Lutomirski
2015-12-30 4:12 ` [PATCH v3 6/7] x86,vdso: Use .fault instead of remap_pfn_range for the vvar mapping Andy Lutomirski
2016-01-12 12:04 ` [tip:x86/asm] x86/vdso: Use ->fault() instead of remap_pfn_range( ) " tip-bot for Andy Lutomirski
2015-12-30 4:12 ` [PATCH v3 7/7] x86/vdso: Disallow vvar access to vclock IO for never-used vclocks Andy Lutomirski
2016-01-12 12:04 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-01-05 0:02 ` [PATCH v3 0/7] mm, x86/vdso: Special IO mapping improvements Kees Cook
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=d2938d1eb37be7a5e4f86182db646551f11e45aa.1451446564.git.luto@kernel.org \
--to=luto@kernel.org \
--cc=bp@alien8.de \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=x86@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).