From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Tom Lendacky <thomas.lendacky@amd.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>,
Dave Hansen <dave.hansen@intel.com>,
Kai Huang <kai.huang@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/mm: Decouple dynamic __PHYSICAL_MASK from AMD SME
Date: Wed, 14 Feb 2018 07:21:21 +0300 [thread overview]
Message-ID: <20180214042121.tza3cpvrnpztjeme@node.shutemov.name> (raw)
In-Reply-To: <5199949d-6795-aa55-888c-7ba8abd406e2@amd.com>
On Tue, Feb 13, 2018 at 10:10:22PM -0600, Tom Lendacky wrote:
> On 2/8/2018 6:55 AM, Kirill A. Shutemov wrote:
> > AMD SME claims one bit from physical address to indicate whether the
> > page is encrypted or not. To achieve that we clear out the bit from
> > __PHYSICAL_MASK.
>
> I was actually working on a suggestion by Linus to use one of the software
> page table bits to indicate encryption and translate that to the hardware
> bit when writing the actual page table entry. With that, __PHYSICAL_MASK
> would go back to its original definition.
But you would need to mask it on reading of pfn from page table entry,
right? I expect it to have more overhead than this one.
And software bits are valuable. Do we still have a spare one for this?
--
Kirill A. Shutemov
next prev parent reply other threads:[~2018-02-14 4:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-08 12:55 Kirill A. Shutemov
2018-02-14 4:10 ` Tom Lendacky
2018-02-14 4:21 ` Kirill A. Shutemov [this message]
2018-02-14 4:57 ` Tom Lendacky
2018-02-14 7:30 ` Kai Huang
2018-02-14 9:02 ` Kirill A. Shutemov
2018-02-14 15:09 ` Tom Lendacky
2018-02-14 15:51 ` Kirill A. Shutemov
2018-02-14 14:30 ` Tom Lendacky
2018-04-10 9:33 Kirill A. Shutemov
2018-04-20 17:59 ` Kirill A. Shutemov
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