[xen stable-4.18] x86/MTRR: hook mtrr_bp_restore() back up

[patchbot@xxxxxxx]

commit a2b5eafb624357df3aaf8c203c6d520b613b00b0
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 29 12:05:37 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 29 12:05:37 2025 +0200

    x86/MTRR: hook mtrr_bp_restore() back up
    
    Unlike stated in the offending commit's description,
    load_system_tables() wasn't the only thing left to retain from the
    earlier restore_rest_processor_state(). Note that MTRR state was still
    reloaded via mtrr_aps_sync_end(), but that happens quite a bit later in
    the resume process.
    
    While there also do Misra-related tidying for the function itself: The
    function being used from assembly only means it doesn't need to have a
    declaration.
    
    Fixes: 4304ff420e51 ("x86/S3: Drop {save,restore}_rest_processor_state() 
completely")
    Reported-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    master commit: 0414dedd6fde1a1c5c5e38dcbef4dad506e1398c
    master date: 2025-04-03 09:39:13 +0200
---
 xen/arch/x86/acpi/wakeup_prot.S | 2 ++
 xen/arch/x86/include/asm/mtrr.h | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/acpi/wakeup_prot.S b/xen/arch/x86/acpi/wakeup_prot.S
index 3855ff1ddb..66f7993399 100644
--- a/xen/arch/x86/acpi/wakeup_prot.S
+++ b/xen/arch/x86/acpi/wakeup_prot.S
@@ -124,6 +124,8 @@ ENTRY(s3_resume)
         mov     STACK_CPUINFO_FIELD(cr4)(%rbx), %rax
         mov     %rax, %cr4
 
+        call    mtrr_bp_restore
+
 .Lsuspend_err:
         pop     %r15
         pop     %r14
diff --git a/xen/arch/x86/include/asm/mtrr.h b/xen/arch/x86/include/asm/mtrr.h
index 14246e3387..a8d3944d1c 100644
--- a/xen/arch/x86/include/asm/mtrr.h
+++ b/xen/arch/x86/include/asm/mtrr.h
@@ -66,7 +66,6 @@ extern uint8_t pat_type_2_pte_flags(uint8_t pat_type);
 extern int hold_mtrr_updates_on_aps;
 extern void mtrr_aps_sync_begin(void);
 extern void mtrr_aps_sync_end(void);
-extern void mtrr_bp_restore(void);
 
 extern bool_t mtrr_var_range_msr_set(struct domain *, struct mtrr_state *,
                                      uint32_t msr, uint64_t msr_content);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.18