This is a note to let you know that I've just added the patch titled
x86/xen: Fix secondary processors' FPU initialization
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-xen-fix-secondary-processors-fpu-initialization.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fe3e0a13e597c1c8617814bf9b42ab732db5c26e Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@xxxxxxxx>
Date: Mon, 3 Jul 2023 15:00:32 +0200
Subject: x86/xen: Fix secondary processors' FPU initialization
From: Juergen Gross <jgross@xxxxxxxx>
commit fe3e0a13e597c1c8617814bf9b42ab732db5c26e upstream.
Moving the call of fpu__init_cpu() from cpu_init() to start_secondary()
broke Xen PV guests, as those don't call start_secondary() for APs.
Call fpu__init_cpu() in Xen's cpu_bringup(), which is the Xen PV
replacement of start_secondary().
Fixes: b81fac906a8f ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230703130032.22916-1-jgross@xxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/xen/smp_pv.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -30,6 +30,7 @@
#include <asm/desc.h>
#include <asm/cpu.h>
#include <asm/io_apic.h>
+#include <asm/fpu/internal.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
@@ -63,6 +64,7 @@ static void cpu_bringup(void)
cr4_init();
cpu_init();
+ fpu__init_cpu();
touch_softlockup_watchdog();
/* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
Patches currently in stable-queue which might be from jgross@xxxxxxxx are
queue-5.15/x86-mm-fix-poking_init-for-xen-pv-guests.patch
queue-5.15/x86-xen-fix-secondary-processors-fpu-initialization.patch
queue-5.15/xen-netback-fix-buffer-overrun-triggered-by-unusual-packet.patch
