From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Kai Huang <kai.huang@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv2 12/14] x86/mm: Implement page_keyid() using page_ext
Date: Thu, 29 Mar 2018 15:43:38 +0300 [thread overview]
Message-ID: <20180329124338.vxzjpkz3ecyor5uc@node.shutemov.name> (raw)
In-Reply-To: <b4498b2b-5092-b347-e92d-6ebd375fd947@intel.com>
On Wed, Mar 28, 2018 at 09:59:23AM -0700, Dave Hansen wrote:
> On 03/28/2018 09:55 AM, Kirill A. Shutemov wrote:
> > +static inline int page_keyid(struct page *page)
> > +{
> > + if (!mktme_nr_keyids)
> > + return 0;
> > +
> > + return lookup_page_ext(page)->keyid;
> > +}
>
> This doesn't look very optimized. Don't we normally try to use
> X86_FEATURE_* for these checks so that we get the runtime patching *and*
> compile-time optimizations?
I didn't go to micro optimization just yet. I would like to see whole
stack functioning first.
It doesn't make sense to use cpu_feature_enabledX86_FEATURE_TME) as it
would produce false-positives: MKTME enumeration requires MSR read.
We may change mktme_nr_keyids check to a static key here. But this is not
urgent.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2018-03-29 12:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-28 16:55 [PATCHv2 00/14] Partial MKTME enabling Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 01/14] x86/mm: Decouple dynamic __PHYSICAL_MASK from AMD SME Kirill A. Shutemov
2018-04-02 21:12 ` Tom Lendacky
2018-03-28 16:55 ` [PATCHv2 02/14] x86/mm: Mask out KeyID bits from page table entry pfn Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 03/14] mm/shmem: Zero out unused vma fields in shmem_pseudo_vma_init() Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 04/14] mm: Do no merge vma with different encryption KeyIDs Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 05/14] mm/khugepaged: Do not collapse pages in encrypted VMAs Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 06/14] mm/page_alloc: Propagate encryption KeyID through page allocator Kirill A. Shutemov
2018-03-28 17:15 ` Dave Hansen
2018-03-29 12:38 ` Kirill A. Shutemov
2018-03-29 11:20 ` Michal Hocko
2018-03-29 12:37 ` Kirill A. Shutemov
2018-03-29 12:52 ` Michal Hocko
2018-03-29 13:13 ` Kirill A. Shutemov
2018-03-29 13:37 ` Michal Hocko
2018-03-29 14:33 ` Kirill A. Shutemov
2018-03-30 8:07 ` Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 07/14] mm/page_alloc: Add hook in page allocation path for encrypted pages Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 08/14] mm/page_ext: Drop definition of unused PAGE_EXT_DEBUG_POISON Kirill A. Shutemov
2018-03-29 5:32 ` Vinayak Menon
2018-03-28 16:55 ` [PATCHv2 09/14] x86/mm: Introduce variables to store number, shift and mask of KeyIDs Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 10/14] x86/mm: Preserve KeyID on pte_modify() and pgprot_modify() Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 11/14] x86/mm: Implement vma_is_encrypted() and vma_keyid() Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 12/14] x86/mm: Implement page_keyid() using page_ext Kirill A. Shutemov
2018-03-28 16:59 ` Dave Hansen
2018-03-29 12:43 ` Kirill A. Shutemov [this message]
2018-03-28 16:55 ` [PATCHv2 13/14] x86/mm: Implement prep_encrypted_page() Kirill A. Shutemov
2018-03-28 16:55 ` [PATCHv2 14/14] x86: Introduce CONFIG_X86_INTEL_MKTME Kirill A. Shutemov
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=20180329124338.vxzjpkz3ecyor5uc@node.shutemov.name \
--to=kirill@shutemov.name \
--cc=dave.hansen@intel.com \
--cc=hpa@zytor.com \
--cc=kai.huang@linux.intel.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.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