On 19/06/18 23:30, Brian Woods wrote:
> I'm currently seeing an issue where when booting from a recent Linux
> kernel without nospec_store_bypass_disable. There's a NULL pointer
> having to do with a lock. I put some printks in and it seems that in
> arch/x86/kernel/process.c
> that speculative_store_bypass_ht_init isn't getting called which
> initializes the spin lock.
Brian, would you please give the attached patch a try?
Juergen
>From 90a49beee17fe77075a7fdf433c74c5672cfe0d2 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgr...@suse.com>
Date: Wed, 20 Jun 2018 08:21:33 +0200
Subject: [PATCH] x86/xen: add call of speculative_store_bypass_ht_init() to pv
paths
Commit 1f50ddb4f4189243c05926b842dc1a0332195f31 ("x86/speculation:
Handle HT correctly on AMD") added speculative_store_bypass_ht_init()
to the per-cpu initialization sequence.
speculative_store_bypass_ht_init() needs to be called on each cpu for
pv guests, too.
Reported-by: Brian Woods <brian.wo...@amd.com>
Fixes: 1f50ddb4f4189243c05926b842dc1a0332195f31 ("x86/speculation: Handle HT correctly on AMD")
Cc: <sta...@vger.kernel.org>
Signed-off-by: Juergen Gross <jgr...@suse.com>
---
arch/x86/xen/smp_pv.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 2e20ae2fa2d6..e3b18ad49889 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -32,6 +32,7 @@
#include <xen/interface/vcpu.h>
#include <xen/interface/xenpmu.h>
+#include <asm/spec-ctrl.h>
#include <asm/xen/interface.h>
#include <asm/xen/hypercall.h>
@@ -70,6 +71,8 @@ static void cpu_bringup(void)
cpu_data(cpu).x86_max_cores = 1;
set_cpu_sibling_map(cpu);
+ speculative_store_bypass_ht_init();
+
xen_setup_cpu_clockevents();
notify_cpu_starting(cpu);
@@ -250,6 +253,8 @@ static void __init xen_pv_smp_prepare_cpus(unsigned int max_cpus)
}
set_cpu_sibling_map(0);
+ speculative_store_bypass_ht_init();
+
xen_pmu_init(0);
if (xen_smp_intr_init(0) || xen_smp_intr_init_pv(0))
--
2.13.7
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