| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1396445259-27670-11-git-send-email-Waiman.Long@hp.com>
Date: Wed, 2 Apr 2014 09:27:39 -0400
From: Waiman Long <Waiman.Long@...com>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
Peter Zijlstra <peterz@...radead.org>
Cc: linux-arch@...r.kernel.org, x86@...nel.org,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux-foundation.org,
xen-devel@...ts.xenproject.org, kvm@...r.kernel.org,
Paolo Bonzini <paolo.bonzini@...il.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Rik van Riel <riel@...hat.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>,
David Vrabel <david.vrabel@...rix.com>,
Oleg Nesterov <oleg@...hat.com>,
Gleb Natapov <gleb@...hat.com>,
Aswin Chandramouleeswaran <aswin@...com>,
Scott J Norton <scott.norton@...com>,
Chegu Vinod <chegu_vinod@...com>,
Waiman Long <Waiman.Long@...com>
Subject: [PATCH v8 10/10] pvqspinlock, x86: Enable qspinlock PV support for XEN
This patch adds the necessary KVM specific code to allow XEN to support
the sleeping and CPU kicking operations needed by the queue spinlock PV
code.
Signed-off-by: Waiman Long <Waiman.Long@...com>
---
arch/x86/xen/spinlock.c | 119 +++++++++++++++++++++++++++++++++++++++++++++--
kernel/Kconfig.locks | 2 +-
2 files changed, 115 insertions(+), 6 deletions(-)
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 06f4a64..6bbe798 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -17,6 +17,12 @@
#include "xen-ops.h"
#include "debugfs.h"
+static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
+static DEFINE_PER_CPU(char *, irq_name);
+static bool xen_pvspin = true;
+
+#ifndef CONFIG_QUEUE_SPINLOCK
+
enum xen_contention_stat {
TAKEN_SLOW,
TAKEN_SLOW_PICKUP,
@@ -100,12 +106,9 @@ struct xen_lock_waiting {
__ticket_t want;
};
-static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
-static DEFINE_PER_CPU(char *, irq_name);
static DEFINE_PER_CPU(struct xen_lock_waiting, lock_waiting);
static cpumask_t waiting_cpus;
-static bool xen_pvspin = true;
__visible void xen_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
{
int irq = __this_cpu_read(lock_kicker_irq);
@@ -213,6 +216,94 @@ static void xen_unlock_kick(struct arch_spinlock *lock, __ticket_t next)
}
}
+#else /* CONFIG_QUEUE_SPINLOCK */
+
+#ifdef CONFIG_XEN_DEBUG_FS
+static u32 kick_stats; /* CPU kick count */
+static u32 kick_nohalt_stats; /* Kick but not halt count */
+static u32 halt_qhead_stats; /* Queue head halting count */
+static u32 halt_qnode_stats; /* Queue node halting count */
+static u32 wake_kick_stats; /* Wakeup by kicking count */
+static u32 wake_spur_stats; /* Spurious wakeup count */
+
+static inline void xen_kick_stats(void)
+{
+ add_smp(&kick_stats, 1);
+}
+
+static inline void xen_halt_stats(enum pv_lock_stats type)
+{
+ if (type == PV_HALT_QHEAD)
+ add_smp(&halt_qhead_stats, 1);
+ else /* type == PV_HALT_QNODE */
+ add_smp(&halt_qnode_stats, 1);
+}
+
+static inline void xen_lock_stats(enum pv_lock_stats type)
+{
+ if (type == PV_WAKE_KICKED)
+ add_smp(&wake_kick_stats, 1);
+ else if (type == PV_WAKE_SPURIOUS)
+ add_smp(&wake_spur_stats, 1);
+ else /* type == PV_KICK_NOHALT */
+ add_smp(&kick_nohalt_stats, 1);
+}
+#else /* CONFIG_XEN_DEBUG_FS */
+static inline void xen_kick_stats(void)
+{
+}
+
+static inline void xen_halt_stats(enum pv_lock_stats type)
+{
+}
+
+static inline void xen_lock_stats(enum pv_lock_stats type)
+{
+}
+#endif /* CONFIG_XEN_DEBUG_FS */
+
+static void xen_kick_cpu(int cpu)
+{
+ xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
+ xen_kick_stats();
+}
+
+/*
+ * Halt the current CPU & release it back to the host
+ */
+static void xen_hibernate(enum pv_lock_stats type)
+{
+ int irq = __this_cpu_read(lock_kicker_irq);
+ unsigned long flags;
+
+ /* If kicker interrupts not initialized yet, just spin */
+ if (irq == -1)
+ return;
+
+ /*
+ * Make sure an interrupt handler can't upset things in a
+ * partially setup state.
+ */
+ local_irq_save(flags);
+
+ xen_halt_stats(type);
+ /* clear pending */
+ xen_clear_irq_pending(irq);
+
+ /* Allow interrupts while blocked */
+ local_irq_restore(flags);
+
+ /*
+ * If an interrupt happens here, it will leave the wakeup irq
+ * pending, which will cause xen_poll_irq() to return
+ * immediately.
+ */
+
+ /* Block until irq becomes pending (or perhaps a spurious wakeup) */
+ xen_poll_irq(irq);
+}
+#endif /* CONFIG_QUEUE_SPINLOCK */
+
static irqreturn_t dummy_handler(int irq, void *dev_id)
{
BUG();
@@ -258,7 +349,6 @@ void xen_uninit_lock_cpu(int cpu)
per_cpu(irq_name, cpu) = NULL;
}
-
/*
* Our init of PV spinlocks is split in two init functions due to us
* using paravirt patching and jump labels patching and having to do
@@ -275,8 +365,14 @@ void __init xen_init_spinlocks(void)
return;
}
+#ifdef CONFIG_QUEUE_SPINLOCK
+ pv_lock_ops.kick_cpu = xen_kick_cpu;
+ pv_lock_ops.hibernate = xen_hibernate;
+ pv_lock_ops.lockstat = xen_lock_stats;
+#else
pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
pv_lock_ops.unlock_kick = xen_unlock_kick;
+#endif
}
/*
@@ -318,6 +414,7 @@ static int __init xen_spinlock_debugfs(void)
d_spin_debug = debugfs_create_dir("spinlocks", d_xen);
+#ifndef CONFIG_QUEUE_SPINLOCK
debugfs_create_u8("zero_stats", 0644, d_spin_debug, &zero_stats);
debugfs_create_u32("taken_slow", 0444, d_spin_debug,
@@ -337,7 +434,19 @@ static int __init xen_spinlock_debugfs(void)
debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1);
-
+#else /* CONFIG_QUEUE_SPINLOCK */
+ debugfs_create_u32("kick_stats", 0644, d_spin_debug, &kick_stats);
+ debugfs_create_u32("kick_nohalt_stats",
+ 0644, d_spin_debug, &kick_nohalt_stats);
+ debugfs_create_u32("halt_qhead_stats",
+ 0644, d_spin_debug, &halt_qhead_stats);
+ debugfs_create_u32("halt_qnode_stats",
+ 0644, d_spin_debug, &halt_qnode_stats);
+ debugfs_create_u32("wake_kick_stats",
+ 0644, d_spin_debug, &wake_kick_stats);
+ debugfs_create_u32("wake_spur_stats",
+ 0644, d_spin_debug, &wake_spur_stats);
+#endif /* CONFIG_QUEUE_SPINLOCK */
return 0;
}
fs_initcall(xen_spinlock_debugfs);
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index a70fdeb..451e392 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -229,4 +229,4 @@ config ARCH_USE_QUEUE_SPINLOCK
config QUEUE_SPINLOCK
def_bool y if ARCH_USE_QUEUE_SPINLOCK
- depends on SMP && (!PARAVIRT_SPINLOCKS || !XEN)
+ depends on SMP
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists