From: Tom Lendacky <thomas.lendacky@amd.com>
To: <linux-arch@vger.kernel.org>, <linux-efi@vger.kernel.org>,
<kvm@vger.kernel.org>, <linux-doc@vger.kernel.org>,
<x86@kernel.org>, <linux-kernel@vger.kernel.org>,
<kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
<iommu@lists.linux-foundation.org>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Jonathan Corbet" <corbet@lwn.net>,
"Matt Fleming" <matt@codeblueprint.co.uk>,
"Joerg Roedel" <joro@8bytes.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Alexander Potapenko" <glider@google.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Dmitry Vyukov" <dvyukov@google.com>
Subject: [RFC PATCH v1 01/18] x86: Set the write-protect cache mode for AMD processors
Date: Tue, 26 Apr 2016 17:45:20 -0500 [thread overview]
Message-ID: <20160426224520.13079.67248.stgit@tlendack-t1.amdoffice.net> (raw)
In-Reply-To: <20160426224508.13079.90373.stgit@tlendack-t1.amdoffice.net>
For AMD processors that support PAT, set the write-protect cache mode
(_PAGE_CACHE_MODE_WP) entry to the actual write-protect value (x05).
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/mm/pat.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index fb0604f..dda78ed 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -345,6 +345,8 @@ void pat_init(void)
* we lose performance without causing a correctness issue.
* Pentium 4 erratum N46 is an example for such an erratum,
* although we try not to use PAT at all on affected CPUs.
+ * AMD processors support write-protect so initialize the
+ * PAT slot 5 appropriately.
*
* PTE encoding:
* PAT
@@ -356,7 +358,7 @@ void pat_init(void)
* 010 2 UC-: _PAGE_CACHE_MODE_UC_MINUS
* 011 3 UC : _PAGE_CACHE_MODE_UC
* 100 4 WB : Reserved
- * 101 5 WC : Reserved
+ * 101 5 WC : Reserved (AMD: _PAGE_CACHE_MODE_WP)
* 110 6 UC-: Reserved
* 111 7 WT : _PAGE_CACHE_MODE_WT
*
@@ -364,7 +366,12 @@ void pat_init(void)
* corresponding types in the presence of PAT errata.
*/
pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
- PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, WT);
+ PAT(4, WB) | PAT(6, UC_MINUS) | PAT(7, WT);
+
+ if (c->x86_vendor == X86_VENDOR_AMD)
+ pat |= PAT(5, WP);
+ else
+ pat |= PAT(5, WC);
}
if (!boot_cpu_done) {
next prev parent reply other threads:[~2016-04-26 23:01 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-26 22:45 [RFC PATCH v1 00/18] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-04-26 22:45 ` Tom Lendacky [this message]
2016-04-26 22:45 ` [RFC PATCH v1 02/18] x86: Secure Memory Encryption (SME) build enablement Tom Lendacky
2016-04-26 22:45 ` [RFC PATCH v1 03/18] x86: Secure Memory Encryption (SME) support Tom Lendacky
2016-04-26 22:45 ` [RFC PATCH v1 04/18] x86: Add the Secure Memory Encryption cpu feature Tom Lendacky
2016-04-26 22:46 ` [RFC PATCH v1 05/18] x86: Handle reduction in physical address size with SME Tom Lendacky
2016-04-26 22:46 ` [RFC PATCH v1 06/18] x86: Provide general kernel support for memory encryption Tom Lendacky
2016-04-26 22:46 ` [RFC PATCH v1 07/18] x86: Extend the early_memmap support with additional attrs Tom Lendacky
2016-04-26 22:46 ` [RFC PATCH v1 08/18] x86: Add support for early encryption/decryption of memory Tom Lendacky
2016-04-26 22:46 ` [RFC PATCH v1 09/18] x86: Insure that memory areas are encrypted when possible Tom Lendacky
2016-04-26 22:47 ` [RFC PATCH v1 10/18] x86/efi: Access EFI related tables in the clear Tom Lendacky
2016-04-26 22:55 [RFC PATCH v1 00/18] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-04-26 22:56 ` [RFC PATCH v1 01/18] x86: Set the write-protect cache mode for AMD processors Tom Lendacky
2016-04-27 14:33 ` Andy Lutomirski
2016-04-27 14:44 ` Tom Lendacky
2016-04-27 14:47 ` Andy Lutomirski
2016-04-27 15:05 ` Tom Lendacky
2016-04-27 15:12 ` Andy Lutomirski
2016-04-27 15:31 ` Borislav Petkov
2016-04-27 15:34 ` Andy Lutomirski
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