0004-x86-S3-Restore-Xen-s-MSR_PAT-value-on-S3-resume.patch


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From 7b1b9849e8a0d7791866d6d21c45993dfe27836c Mon Sep 17 00:00:00 2001
From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Tue, 7 Feb 2023 17:03:09 +0100
Subject: [PATCH 04/61] x86/S3: Restore Xen's MSR_PAT value on S3 resume

There are two paths in the trampoline, and Xen's PAT needs setting up in both,
not just the boot path.

Fixes: 4304ff420e51 ("x86/S3: Drop {save,restore}_rest_processor_state() completely")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 4d975798e11579fdf405b348543061129e01b0fb
master date: 2023-01-10 21:21:30 +0000
---
 xen/arch/x86/boot/wakeup.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xen/arch/x86/boot/wakeup.S b/xen/arch/x86/boot/wakeup.S
index c17d613b61..08447e1934 100644
--- a/xen/arch/x86/boot/wakeup.S
+++ b/xen/arch/x86/boot/wakeup.S
@@ -130,6 +130,11 @@ wakeup_32:
         and     %edi, %edx
         wrmsr
 1:
+        /* Set up PAT before enabling paging. */
+        mov     $XEN_MSR_PAT & 0xffffffff, %eax
+        mov     $XEN_MSR_PAT >> 32, %edx
+        mov     $MSR_IA32_CR_PAT, %ecx
+        wrmsr
 
         /* Set up EFER (Extended Feature Enable Register). */
         movl    $MSR_EFER,%ecx
-- 
2.40.0