[PATCH 4.9 089/107] x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicolai Stange <nsta...@suse.de>

commit ffcba43ff66c7dab34ec700debd491d2a4d319b4 upstream

The last missing piece to having vmx_l1d_flush() take interrupts after
VMEXIT into account is to set the kvm_cpu_l1tf_flush_l1d per-cpu flag on
irq entry.

Issue calls to kvm_set_cpu_l1tf_flush_l1d() from entering_irq(),
ipi_entering_ack_irq(), smp_reschedule_interrupt() and
uv_bau_message_interrupt().

Suggested-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Nicolai Stange <nsta...@suse.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/x86/include/asm/apic.h   |    3 +++
 arch/x86/kernel/smp.c         |    1 +
 arch/x86/platform/uv/tlb_uv.c |    1 +
 3 files changed, 5 insertions(+)

--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -12,6 +12,7 @@
 #include <asm/mpspec.h>
 #include <asm/msr.h>
 #include <asm/idle.h>
+#include <asm/hardirq.h>
 
 #define ARCH_APICTIMER_STOPS_ON_C3     1
 
@@ -647,6 +648,7 @@ static inline void entering_irq(void)
 {
        irq_enter();
        exit_idle();
+       kvm_set_cpu_l1tf_flush_l1d();
 }
 
 static inline void entering_ack_irq(void)
@@ -659,6 +661,7 @@ static inline void ipi_entering_ack_irq(
 {
        irq_enter();
        ack_APIC_irq();
+       kvm_set_cpu_l1tf_flush_l1d();
 }
 
 static inline void exiting_irq(void)
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -271,6 +271,7 @@ __visible void __irq_entry smp_reschedul
        /*
         * KVM uses this interrupt to force a cpu out of guest mode
         */
+       kvm_set_cpu_l1tf_flush_l1d();
 }
 
 __visible void __irq_entry smp_trace_reschedule_interrupt(struct pt_regs *regs)
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1283,6 +1283,7 @@ void uv_bau_message_interrupt(struct pt_
        struct msg_desc msgdesc;
 
        ack_APIC_irq();
+       kvm_set_cpu_l1tf_flush_l1d();
        time_start = get_cycles();
 
        bcp = &per_cpu(bau_control, smp_processor_id());