linux-kernel - [PATCH v2] x86/xen/pvh: Enable PAE mode for 32-bit guest only when CONFIG_X86

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <0469c27833be58aa66471920aa77922489d86c63.1713873613.git.houwenlong.hwl@antgroup.com>
Date: Tue, 23 Apr 2024 20:00:58 +0800
From: "Hou Wenlong" <houwenlong.hwl@...group.com>
To: linux-kernel@...r.kernel.org
Cc: "Hou Wenlong" <houwenlong.hwl@...group.com>,
  "Juergen Gross" <jgross@...e.com>,
  "Boris Ostrovsky" <boris.ostrovsky@...cle.com>,
  "Thomas Gleixner" <tglx@...utronix.de>,
  "Ingo Molnar" <mingo@...hat.com>,
  "Borislav Petkov" <bp@...en8.de>,
  "Dave Hansen" <dave.hansen@...ux.intel.com>,
   <x86@...nel.org>,
  "H. Peter Anvin" <hpa@...or.com>,
   <xen-devel@...ts.xenproject.org>
Subject: [PATCH v2] x86/xen/pvh: Enable PAE mode for 32-bit guest only when CONFIG_X86_PAE is set

The PVH entry is available for 32-bit KVM guests, and 32-bit KVM guests
do not depend on CONFIG_X86_PAE. However, mk_early_pgtbl_32() builds
different pagetables depending on whether CONFIG_X86_PAE is set.
Therefore, enabling PAE mode for 32-bit KVM guests without
CONFIG_X86_PAE being set would result in a boot failure during CR3
loading.

Signed-off-by: Hou Wenlong <houwenlong.hwl@...group.com>
Reviewed-by: Juergen Gross <jgross@...e.com>
---
v1 -> v2: Add the "Reviewed-by" tag from Juergen
v1: https://lore.kernel.org/lkml/8c5448eeebbba998a7fff9ed9b2f7e7f3e437967.1697792461.git.houwenlong.hwl@antgroup.com
---
 arch/x86/platform/pvh/head.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S
index f7235ef87bc3..18c69d213458 100644
--- a/arch/x86/platform/pvh/head.S
+++ b/arch/x86/platform/pvh/head.S
@@ -71,10 +71,12 @@ SYM_CODE_START_LOCAL(pvh_start_xen)

 	mov $_pa(early_stack_end), %esp

+#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
 	/* Enable PAE mode. */
 	mov %cr4, %eax
 	orl $X86_CR4_PAE, %eax
 	mov %eax, %cr4
+#endif

 #ifdef CONFIG_X86_64
 	/* Enable Long mode. */
-- 
2.31.1