diff --git a/MAINTAINERS b/MAINTAINERS
index a5de093e5e0b..e4647c84c987 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18875,6 +18875,15 @@ S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/core
 F:	arch/x86/platform
 
+X86 PLATFORM UV HPE SUPERDOME FLEX
+M:	Steve Wahl <steve.wahl@hpe.com>
+R:	Dimitri Sivanich <dimitri.sivanich@hpe.com>
+R:	Russ Anderson <russ.anderson@hpe.com>
+S:	Supported
+F:	arch/x86/include/asm/uv/
+F:	arch/x86/kernel/apic/x2apic_uv_x.c
+F:	arch/x86/platform/uv/
+
 X86 VDSO
 M:	Andy Lutomirski <luto@kernel.org>
 L:	linux-kernel@vger.kernel.org
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index dae32d948bf2..f8a56b5dc29f 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -161,6 +161,7 @@ static void apic_update_vector(struct irq_data *irqd, unsigned int newvec,
 		apicd->move_in_progress = true;
 		apicd->prev_vector = apicd->vector;
 		apicd->prev_cpu = apicd->cpu;
+		WARN_ON_ONCE(apicd->cpu == newcpu);
 	} else {
 		irq_matrix_free(vector_matrix, apicd->cpu, apicd->vector,
 				managed);
@@ -910,7 +911,7 @@ void send_cleanup_vector(struct irq_cfg *cfg)
 		__send_cleanup_vector(apicd);
 }
 
-static void __irq_complete_move(struct irq_cfg *cfg, unsigned vector)
+void irq_complete_move(struct irq_cfg *cfg)
 {
 	struct apic_chip_data *apicd;
 
@@ -918,15 +919,16 @@ static void __irq_complete_move(struct irq_cfg *cfg, unsigned vector)
 	if (likely(!apicd->move_in_progress))
 		return;
 
-	if (vector == apicd->vector && apicd->cpu == smp_processor_id())
+	/*
+	 * If the interrupt arrived on the new target CPU, cleanup the
+	 * vector on the old target CPU. A vector check is not required
+	 * because an interrupt can never move from one vector to another
+	 * on the same CPU.
+	 */
+	if (apicd->cpu == smp_processor_id())
 		__send_cleanup_vector(apicd);
 }
 
-void irq_complete_move(struct irq_cfg *cfg)
-{
-	__irq_complete_move(cfg, ~get_irq_regs()->orig_ax);
-}
-
 /*
  * Called from fixup_irqs() with @desc->lock held and interrupts disabled.
  */
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 27aa04a95702..f5ef689dd62a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1594,14 +1594,28 @@ int native_cpu_disable(void)
 	if (ret)
 		return ret;
 
-	/*
-	 * Disable the local APIC. Otherwise IPI broadcasts will reach
-	 * it. It still responds normally to INIT, NMI, SMI, and SIPI
-	 * messages.
-	 */
-	apic_soft_disable();
 	cpu_disable_common();
 
+        /*
+         * Disable the local APIC. Otherwise IPI broadcasts will reach
+         * it. It still responds normally to INIT, NMI, SMI, and SIPI
+         * messages.
+         *
+         * Disabling the APIC must happen after cpu_disable_common()
+         * which invokes fixup_irqs().
+         *
+         * Disabling the APIC preserves already set bits in IRR, but
+         * an interrupt arriving after disabling the local APIC does not
+         * set the corresponding IRR bit.
+         *
+         * fixup_irqs() scans IRR for set bits so it can raise a not
+         * yet handled interrupt on the new destination CPU via an IPI
+         * but obviously it can't do so for IRR bits which are not set.
+         * IOW, interrupts arriving after disabling the local APIC will
+         * be lost.
+         */
+	apic_soft_disable();
+
 	return 0;
 }
 
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 30cc217b8631..651a4ad6d711 100644
--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -380,6 +380,13 @@ int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
 	unsigned int cpu, bit;
 	struct cpumap *cm;
 
+	/*
+	 * Not required in theory, but matrix_find_best_cpu() uses
+	 * for_each_cpu() which ignores the cpumask on UP .
+	 */
+	if (cpumask_empty(msk))
+		return -EINVAL;
+
 	cpu = matrix_find_best_cpu(m, msk);
 	if (cpu == UINT_MAX)
 		return -ENOSPC;