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From:   Juergen Gross <jgross@suse.com>
To:     linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org,
        x86@kernel.org
Cc:     Juergen Gross <jgross@suse.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
Date:   Fri,  4 Nov 2022 08:27:00 +0100
Message-Id: <20221104072701.20283-5-jgross@suse.com>
In-Reply-To: <20221104072701.20283-1-jgross@suse.com>
References: <20221104072701.20283-1-jgross@suse.com>
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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 not supporting
32-bit mode.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- new patch
---
 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 6c2f1b76a0b6..42cd96e7d733 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
 
-- 
2.35.3