linux-kernel - [tip: x86/cpu] x86/cpu: Remove X86_FEATURE_XENPV usage in setup_cpu_entry

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Date:   Tue, 22 Nov 2022 18:04:47 -0000
From:   "tip-bot2 for Juergen Gross" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Juergen Gross <jgross@...e.com>, Borislav Petkov <bp@...e.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/cpu] x86/cpu: Remove X86_FEATURE_XENPV usage in
 setup_cpu_entry_area()

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     d76c4f7a610ac56c5b06e34258859945e77d190c
Gitweb:        https://git.kernel.org/tip/d76c4f7a610ac56c5b06e34258859945e77d190c
Author:        Juergen Gross <jgross@...e.com>
AuthorDate:    Fri, 04 Nov 2022 08:27:00 +01:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Tue, 22 Nov 2022 16:16:25 +01:00

x86/cpu: Remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()

Testing of X86_FEATURE_XENPV in setup_cpu_entry_area() can be removed,
as this code path is 32-bit only, and Xen PV guests are 64-bit only.

Signed-off-by: Juergen Gross <jgross@...e.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Acked-by: Dave Hansen <dave.hansen@...ux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-5-jgross@suse.com
---
 arch/x86/mm/cpu_entry_area.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 6c2f1b7..42cd96e 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -138,17 +138,13 @@ static void __init setup_cpu_entry_area(unsigned int cpu)
 	pgprot_t tss_prot = PAGE_KERNEL_RO;
 #else
 	/*
-	 * On native 32-bit systems, the GDT cannot be read-only because
+	 * On 32-bit systems, the GDT cannot be read-only because
 	 * our double fault handler uses a task gate, and entering through
 	 * a task gate needs to change an available TSS to busy.  If the
 	 * GDT is read-only, that will triple fault.  The TSS cannot be
 	 * read-only because the CPU writes to it on task switches.
-	 *
-	 * On Xen PV, the GDT must be read-only because the hypervisor
-	 * requires it.
 	 */
-	pgprot_t gdt_prot = boot_cpu_has(X86_FEATURE_XENPV) ?
-		PAGE_KERNEL_RO : PAGE_KERNEL;
+	pgprot_t gdt_prot = PAGE_KERNEL;
 	pgprot_t tss_prot = PAGE_KERNEL;
 #endif