From: Dave Hansen <dave.hansen@linux.intel.com>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
luto@kernel.org, torvalds@linux-foundation.org,
keescook@google.com, hughd@google.com, jgross@suse.com,
x86@kernel.org
Subject: Re: [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL
Date: Fri, 16 Feb 2018 15:19:00 -0800 [thread overview]
Message-ID: <562aaaf0-fb8e-1cc8-61eb-1d74b5922714@linux.intel.com> (raw)
In-Reply-To: <DF43D1DD-42EE-4545-9F54-4BC2395D66EA@gmail.com>
On 02/16/2018 10:25 AM, Nadav Amit wrote:
>> --- a/arch/x86/mm/pageattr.c~kpti-no-global-for-kernel-mappings 2018-02-13 15:17:56.148210060 -0800
>> +++ b/arch/x86/mm/pageattr.c 2018-02-13 15:17:56.153210060 -0800
>> @@ -593,7 +593,8 @@ try_preserve_large_page(pte_t *kpte, uns
>> * different bit positions in the two formats.
>> */
>> req_prot = pgprot_4k_2_large(req_prot);
>> - req_prot = pgprot_set_on_present(req_prot, _PAGE_GLOBAL | _PAGE_PSE);
>> + req_prot = pgprot_set_on_present(req_prot,
>> + __PAGE_KERNEL_GLOBAL | _PAGE_PSE);
>> req_prot = canon_pgprot(req_prot);
> From these chunks, it seems to me as req_prot will not have the global bit
> on when a??noptia?? parameter is provided. What am I missing?
BTW, this code is broken. It's trying to unconditionally set
_PAGE_GLOBAL whenever set do change_page_attr() and friends. It gets
fixed up by canon_pgprot(), but it's wrong to do in the first place.
I've got a better fix for this coming.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2018-02-16 23:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-15 13:20 [PATCH 0/3] Use global pages with PTI Dave Hansen
2018-02-15 13:20 ` [PATCH 1/3] x86/mm: factor out conditional pageattr PTE bit setting code Dave Hansen
2018-02-15 13:20 ` [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL Dave Hansen
2018-02-16 17:47 ` Nadav Amit
2018-02-16 18:03 ` Dave Hansen
2018-02-16 18:25 ` Nadav Amit
2018-02-16 19:06 ` Dave Hansen
2018-02-16 19:54 ` Nadav Amit
2018-02-16 20:00 ` Dave Hansen
2018-02-16 23:19 ` Dave Hansen [this message]
2018-02-15 13:20 ` [PATCH 3/3] x86/pti: enable global pages for shared areas Dave Hansen
2018-02-15 17:47 ` [PATCH 0/3] Use global pages with PTI Linus Torvalds
2018-02-15 18:13 ` Dave Hansen
2018-02-15 23:55 ` Dave Hansen
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=562aaaf0-fb8e-1cc8-61eb-1d74b5922714@linux.intel.com \
--to=dave.hansen@linux.intel.com \
--cc=hughd@google.com \
--cc=jgross@suse.com \
--cc=keescook@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=nadav.amit@gmail.com \
--cc=torvalds@linux-foundation.org \
--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).