The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 74899d92e66663dc7671a8017b3146dcd4735f3b Mon Sep 17 00:00:00 2001

From: Juergen Gross jgross@suse.com Date: Thu, 21 Jun 2018 10:43:31 +0200 Subject: [PATCH] x86/xen: Add call of speculative_store_bypass_ht_init() to PV paths

Commit:

1f50ddb4f418 ("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.woods@amd.com Tested-by: Brian Woods brian.woods@amd.com Signed-off-by: Juergen Gross jgross@suse.com Cc: stable@vger.kernel.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: boris.ostrovsky@oracle.com Cc: xen-devel@lists.xenproject.org Fixes: 1f50ddb4f4189243c05926b842dc1a0332195f31 ("x86/speculation: Handle HT correctly on AMD") Link: https://lore.kernel.org/lkml/20180621084331.21228-1-jgross@suse.com Signed-off-by: Ingo Molnar mingo@kernel.org

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))