lkml.org 
[lkml]   [2018]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/mm] x86/mm: Update comment in detect_tme() regarding x86_phys_bits
Commit-ID:  547edaca247abf910e32f0cd883ba83b8fc6d0ed
Gitweb: https://git.kernel.org/tip/547edaca247abf910e32f0cd883ba83b8fc6d0ed
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Thu, 15 Mar 2018 16:49:06 +0300
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 27 Mar 2018 11:49:58 +0200

x86/mm: Update comment in detect_tme() regarding x86_phys_bits

As Kai pointed out, the primary reason for adjusting x86_phys_bits is to
reflect that the the address space is reduced and not the ability to
communicate the available physical address space to virtual machines.

Suggested-by: Kai Huang <kai.huang@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: linux-mm@kvack.org
Link: https://lkml.kernel.org/r/20180315134907.9311-2-kirill.shutemov@linux.intel.com

---
arch/x86/kernel/cpu/intel.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 3f8d7a3b6447..6106d11ceb6b 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -587,11 +587,8 @@ detect_keyid_bits:
}

/*
- * Exclude KeyID bits from physical address bits.
- *
- * We have to do this even if we are not going to use KeyID bits
- * ourself. VM guests still have to know that these bits are not usable
- * for physical address.
+ * KeyID bits effectively lower the number of physical address
+ * bits. Update cpuinfo_x86::x86_phys_bits accordingly.
*/
c->x86_phys_bits -= keyid_bits;
}
\
 
 \ /
  Last update: 2018-03-27 11:56    [W:0.054 / U:0.340 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site