OS-7149 HT exclusion needs cleanup

Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Jerry Jelinek <jerry.jelinek@joyent.com>

6 files changed, 57 insertions, 27 deletions

diff --git a/usr/src/pkg/manifests/system-header.mf b/usr/src/pkg/manifests/system-header.mf
index f3721b3ce8..3f62bda986 100644
--- a/usr/src/pkg/manifests/system-header.mf
+++ b/usr/src/pkg/manifests/system-header.mf
@@ -1675,6 +1675,7 @@ $(i386_ONLY)file path=usr/platform/i86pc/include/sys/cram.h
 $(i386_ONLY)file path=usr/platform/i86pc/include/sys/ddi_subrdefs.h
 $(i386_ONLY)file path=usr/platform/i86pc/include/sys/debug_info.h
 $(i386_ONLY)file path=usr/platform/i86pc/include/sys/fastboot.h
+$(i386_ONLY)file path=usr/platform/i86pc/include/sys/ht.h
 $(i386_ONLY)file path=usr/platform/i86pc/include/sys/mach_mmu.h
 $(i386_ONLY)file path=usr/platform/i86pc/include/sys/machclock.h
 $(i386_ONLY)file path=usr/platform/i86pc/include/sys/machcpuvar.h
@@ -1730,6 +1731,7 @@ $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/errclassify.h
 $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/fhc.h
 $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/gpio_87317.h
 $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/hpc3130_events.h
+$(sparc_ONLY)file path=usr/platform/sun4u/include/sys/ht.h
 $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/i2c/clients/hpc3130.h
 $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/i2c/clients/i2c_client.h
 $(sparc_ONLY)file path=usr/platform/sun4u/include/sys/i2c/clients/lm75.h
@@ -1793,6 +1795,7 @@ $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/dvma.h
 $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/eeprom.h
 $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/fcode.h
 $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/hsvc.h
+$(sparc_ONLY)file path=usr/platform/sun4v/include/sys/ht.h
 $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/hypervisor_api.h
 $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/idprom.h
 $(sparc_ONLY)file path=usr/platform/sun4v/include/sys/intr.h
diff --git a/usr/src/uts/i86pc/io/apix/apix_utils.c b/usr/src/uts/i86pc/io/apix/apix_utils.c
index 0bdc7c6cc9..268aa5a391 100644
--- a/usr/src/uts/i86pc/io/apix/apix_utils.c
+++ b/usr/src/uts/i86pc/io/apix/apix_utils.c
@@ -29,6 +29,7 @@
 /*
  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  * Copyright 2013 Pluribus Networks, Inc.
+ * Copyright 2018 Joyent, Inc.
  */
 
 #include <sys/processor.h>
@@ -66,6 +67,7 @@
 #include <sys/x_call.h>
 #include <sys/reboot.h>
 #include <sys/apix.h>
+#include <sys/ht.h>
 
 static int apix_get_avail_vector_oncpu(uint32_t, int, int);
 static apix_vector_t *apix_init_vector(processorid_t, uchar_t);
@@ -803,6 +805,9 @@ apix_insert_av(apix_vector_t *vecp, void *intr_id, avfunc f, caddr_t arg1,
 
 	vecp->v_share++;
 	vecp->v_pri = (ipl > vecp->v_pri) ? ipl : vecp->v_pri;
+
+	ht_intr_alloc_pil(vecp->v_pri);
+
 	if (vecp->v_autovect == NULL) {	/* Nothing on list - put it at head */
 		vecp->v_autovect = mem;
 		return;
@@ -1468,7 +1473,7 @@ apix_rebind(apix_vector_t *vecp, processorid_t newcpu, int count)
 	if (!apix_is_cpu_enabled(newcpu))
 		return (NULL);
 
-	if (vecp->v_cpuid == newcpu) 	/* rebind to the same cpu */
+	if (vecp->v_cpuid == newcpu)	/* rebind to the same cpu */
 		return (vecp);
 
 	APIX_ENTER_CPU_LOCK(oldcpu);
diff --git a/usr/src/uts/i86pc/io/pcplusmp/apic.c b/usr/src/uts/i86pc/io/pcplusmp/apic.c
index 0649afa3f3..9d1f0962fc 100644
--- a/usr/src/uts/i86pc/io/pcplusmp/apic.c
+++ b/usr/src/uts/i86pc/io/pcplusmp/apic.c
@@ -82,6 +82,7 @@
 #include <sys/hpet.h>
 #include <sys/apic_common.h>
 #include <sys/apic_timer.h>
+#include <sys/ht.h>
 
 /*
  *	Local Function Prototypes
@@ -300,6 +301,11 @@ apic_init(void)
 		apic_ipltopri[j] = (i << APIC_IPL_SHIFT) + APIC_BASE_VECT;
 	apic_init_common();
 
+	/*
+	 * For pcplusmp, we'll keep things simple and always disable this.
+	 */
+	ht_intr_alloc_pil(XC_CPUPOKE_PIL);
+
 	apic_pir_vect = apic_get_ipivect(XC_CPUPOKE_PIL, -1);
 
 #if !defined(__amd64)
diff --git a/usr/src/uts/i86pc/os/ht.c b/usr/src/uts/i86pc/os/ht.c
index f82c51ac08..6e13eaedae 100644
--- a/usr/src/uts/i86pc/os/ht.c
+++ b/usr/src/uts/i86pc/os/ht.c
@@ -138,6 +138,8 @@ CTASSERT(CM_POISONED < (1 << CS_SHIFT));
 CTASSERT(CM_POISONED > CM_VCPU);
 CTASSERT(CM_VCPU > CM_UNSAFE);
 
+static uint_t empty_pil = XC_CPUPOKE_PIL;
+
 /*
  * If disabled, no HT exclusion is performed, and system is potentially
  * vulnerable to L1TF if hyper-threading is enabled, and we don't have the "not
@@ -212,6 +214,23 @@ ht_init(void)
 }
 
 /*
+ * We're adding an interrupt handler of some kind at the given PIL.  If this
+ * happens to be the same PIL as XC_CPUPOKE_PIL, then we need to disable our
+ * pil_needs_kick() optimization, as there is now potentially an unsafe
+ * interrupt handler at that PIL.  This typically won't occur, so we're not that
+ * careful about what's actually getting added, which CPU it's on, or if it gets
+ * removed.  This also presumes that softints can't cover our empty_pil.
+ */
+void
+ht_intr_alloc_pil(uint_t pil)
+{
+	ASSERT(pil <= PIL_MAX);
+
+	if (empty_pil == pil)
+		empty_pil = PIL_MAX + 1;
+}
+
+/*
  * If our sibling is also a VCPU thread from a different zone, we need one of
  * them to give up, otherwise they will just battle each other for exclusion
  * until they exhaust their quantum.
@@ -370,41 +389,36 @@ ht_kick(cpu_ht_t *ht, zoneid_t zoneid)
 
 	poke_cpu(ht->ch_sib->cpu_id);
 
+	membar_consumer();
+	sibstate = ht->ch_sibstate;
+
+	if (CS_MARK(sibstate) != CM_POISONED || CS_ZONE(sibstate) == zoneid)
+		return;
+
+	lock_clear(&ht->ch_lock);
+
+	/*
+	 * Spin until we can see the sibling has been kicked out or is otherwise
+	 * OK.
+	 */
 	for (;;) {
 		membar_consumer();
 		sibstate = ht->ch_sibstate;
 
 		if (CS_MARK(sibstate) != CM_POISONED ||
 		    CS_ZONE(sibstate) == zoneid)
-			return;
-
-		lock_clear(&ht->ch_lock);
-
-		for (;;) {
-			membar_consumer();
-			sibstate = ht->ch_sibstate;
-
-			if (CS_MARK(sibstate) != CM_POISONED ||
-			    CS_ZONE(sibstate) == zoneid) {
-				lock_set(&ht->ch_lock);
-				return;
-			}
-
-			SMT_PAUSE();
-		}
+			break;
 
-		lock_set(&ht->ch_lock);
+		SMT_PAUSE();
 	}
+
+	lock_set(&ht->ch_lock);
 }
 
-/*
- * FIXME: do we need a callback in case somebody installs a handler at this PIL
- * ever?
- */
 static boolean_t
 pil_needs_kick(uint_t pil)
 {
-	return (pil != XC_CPUPOKE_PIL);
+	return (pil != empty_pil);
 }
 
 void
@@ -413,6 +427,8 @@ ht_begin_intr(uint_t pil)
 	ulong_t flags;
 	cpu_ht_t *ht;
 
+	ASSERT(pil <= PIL_MAX);
+
 	flags = intr_clear();
 	ht = &CPU->cpu_m.mcpu_ht;
 
@@ -581,8 +597,6 @@ ht_should_run(kthread_t *t, cpu_t *cp)
 pri_t
 ht_adjust_cpu_score(kthread_t *t, struct cpu *cp, pri_t score)
 {
-	cpu_t *sib;
-
 	if (ht_should_run(t, cp))
 		return (score);
 
diff --git a/usr/src/uts/i86pc/sys/ht.h b/usr/src/uts/i86pc/sys/ht.h
index 6b1bfcdd2b..8bb5a0d6d2 100644
--- a/usr/src/uts/i86pc/sys/ht.h
+++ b/usr/src/uts/i86pc/sys/ht.h
@@ -26,6 +26,7 @@ extern "C" {
 struct cpu;
 
 extern void ht_init(void);
+extern void ht_intr_alloc_pil(uint_t);
 
 extern int ht_acquire(void);
 extern void ht_release(void);
diff --git a/usr/src/uts/sun4/sys/ht.h b/usr/src/uts/sun4/sys/ht.h
index 831891979f..6d7b3e37cc 100644
--- a/usr/src/uts/sun4/sys/ht.h
+++ b/usr/src/uts/sun4/sys/ht.h
@@ -27,8 +27,9 @@ extern "C" {
 
 #define	ht_should_run(t, c) (B_TRUE)
 #define	ht_adjust_cpu_score(t, c, p) (p)
-#define	ht_mark_safe(void) {}
-#define	ht_mark_unsafe(void) {}
+#define	ht_begin_unsafe(void) {}
+#define	ht_end_unsafe(void) {}
+#define	ht_end_intr(void) {}
 
 #ifdef	__cplusplus
 }