Displaying 20 results from an estimated 98 matches for "kvm_lock_spin".
2015 Feb 13
3
[PATCH V4] x86 spinlock: Fix memory corruption on completing completions
....c
@@ -609,7 +609,7 @@ static inline void check_zero(void)
u8 ret;
u8 old;
- old = ACCESS_ONCE(zero_stats);
+ old = READ_ONCE(zero_stats);
if (unlikely(old)) {
ret = cmpxchg(&zero_stats, old, 0);
/* This ensures only one fellow resets the stat */
@@ -727,6 +727,7 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
int cpu;
u64 start;
unsigned long flags;
+ __ticket_t head;
if (in_nmi())
return;
@@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
* check again make sure it didn't become free whil...
2015 Feb 13
3
[PATCH V4] x86 spinlock: Fix memory corruption on completing completions
....c
@@ -609,7 +609,7 @@ static inline void check_zero(void)
u8 ret;
u8 old;
- old = ACCESS_ONCE(zero_stats);
+ old = READ_ONCE(zero_stats);
if (unlikely(old)) {
ret = cmpxchg(&zero_stats, old, 0);
/* This ensures only one fellow resets the stat */
@@ -727,6 +727,7 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
int cpu;
u64 start;
unsigned long flags;
+ __ticket_t head;
if (in_nmi())
return;
@@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
* check again make sure it didn't become free whil...
2014 Mar 13
2
[PATCH RFC v6 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM
..._init kvm_spinlock_init(void)
> if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
> return;
>
> +#ifdef CONFIG_QUEUE_SPINLOCK
> + pv_lock_ops.kick_cpu = kvm_kick_cpu_type;
> + pv_lock_ops.hibernate = kvm_hibernate;
> +#else
> pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
> pv_lock_ops.unlock_kick = kvm_unlock_kick;
> +#endif
This should also disable the unfair path.
Paolo
2015 Feb 11
1
[PATCH] x86 spinlock: Fix memory corruption on completing completions
...H_FLAG)
__ticket_unlock_kick(head);
so it can't overflow to .tail?
But probably I missed your concern.
And we we do this, probably it makes sense to add something like
bool tickets_equal(__ticket_t one, __ticket_t two)
{
return (one ^ two) & ~TICKET_SLOWPATH_FLAG;
}
and change kvm_lock_spinning() to use tickets_equal(tickets.head, want), plus
it can have more users in asm/spinlock.h.
Oleg.
2014 Mar 13
2
[PATCH RFC v6 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM
..._init kvm_spinlock_init(void)
> if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
> return;
>
> +#ifdef CONFIG_QUEUE_SPINLOCK
> + pv_lock_ops.kick_cpu = kvm_kick_cpu_type;
> + pv_lock_ops.hibernate = kvm_hibernate;
> +#else
> pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
> pv_lock_ops.unlock_kick = kvm_unlock_kick;
> +#endif
This should also disable the unfair path.
Paolo
2015 Feb 11
1
[PATCH] x86 spinlock: Fix memory corruption on completing completions
...H_FLAG)
__ticket_unlock_kick(head);
so it can't overflow to .tail?
But probably I missed your concern.
And we we do this, probably it makes sense to add something like
bool tickets_equal(__ticket_t one, __ticket_t two)
{
return (one ^ two) & ~TICKET_SLOWPATH_FLAG;
}
and change kvm_lock_spinning() to use tickets_equal(tickets.head, want), plus
it can have more users in asm/spinlock.h.
Oleg.
2015 Feb 15
1
[PATCH V4] x86 spinlock: Fix memory corruption on completing completions
...ssion that slowpath bit is
in tail. You are right, situation could lead to positive max and may
report false contention.
And the "(__ticket_t)" typecast looks unnecessary, it only adds more
> confusuin, but this is cosmetic too.
>
Done.
>> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
>> * check again make sure it didn't become free while
>> * we weren't looking.
>> */
>> - if (ACCESS_ONCE(lock->tickets.head) == want) {
>> + head = READ_ONCE(lock->tickets.head);
>> + if...
2015 Feb 15
1
[PATCH V4] x86 spinlock: Fix memory corruption on completing completions
...ssion that slowpath bit is
in tail. You are right, situation could lead to positive max and may
report false contention.
And the "(__ticket_t)" typecast looks unnecessary, it only adds more
> confusuin, but this is cosmetic too.
>
Done.
>> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
>> * check again make sure it didn't become free while
>> * we weren't looking.
>> */
>> - if (ACCESS_ONCE(lock->tickets.head) == want) {
>> + head = READ_ONCE(lock->tickets.head);
>> + if...
2015 Feb 12
8
[PATCH V3] x86 spinlock: Fix memory corruption on completing completions
...|
- tmp.head != head)
+ if (__tickets_equal(tmp.head, tmp.tail) || tmp.head != head)
break;
cpu_relax();
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 94f6434..e758b46 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -727,6 +727,7 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
int cpu;
u64 start;
unsigned long flags;
+ __ticket_t head;
if (in_nmi())
return;
@@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
* check again make sure it didn't become free whil...
2015 Feb 12
8
[PATCH V3] x86 spinlock: Fix memory corruption on completing completions
...|
- tmp.head != head)
+ if (__tickets_equal(tmp.head, tmp.tail) || tmp.head != head)
break;
cpu_relax();
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 94f6434..e758b46 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -727,6 +727,7 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
int cpu;
u64 start;
unsigned long flags;
+ __ticket_t head;
if (in_nmi())
return;
@@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
* check again make sure it didn't become free whil...
2015 Feb 06
10
[PATCH] x86 spinlock: Fix memory corruption on completing completions
Paravirt spinlock clears slowpath flag after doing unlock.
As explained by Linus currently it does:
prev = *lock;
add_smp(&lock->tickets.head, TICKET_LOCK_INC);
/* add_smp() is a full mb() */
if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))
__ticket_unlock_slowpath(lock, prev);
which
2015 Feb 06
10
[PATCH] x86 spinlock: Fix memory corruption on completing completions
Paravirt spinlock clears slowpath flag after doing unlock.
As explained by Linus currently it does:
prev = *lock;
add_smp(&lock->tickets.head, TICKET_LOCK_INC);
/* add_smp() is a full mb() */
if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))
__ticket_unlock_slowpath(lock, prev);
which
2014 Mar 13
0
[PATCH RFC v6 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM
...vm_para_has_feature(KVM_FEATURE_PV_UNHALT))
>> return;
>>
>> +#ifdef CONFIG_QUEUE_SPINLOCK
>> + pv_lock_ops.kick_cpu = kvm_kick_cpu_type;
>> + pv_lock_ops.hibernate = kvm_hibernate;
>> +#else
>> pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
>> pv_lock_ops.unlock_kick = kvm_unlock_kick;
>> +#endif
>
> This should also disable the unfair path.
>
> Paolo
>
The unfair lock uses a different jump label and does not require any
special PV ops. There is a separate init function for that.
-Longman
2014 Jun 15
0
[PATCH 11/11] qspinlock, kvm: Add paravirt support
...pv_lock_ops.kick_node = PV_CALLEE_SAVE(__pv_kick_node);
+
+ pv_lock_ops.wait_head = PV_CALLEE_SAVE(__pv_wait_head);
+ pv_lock_ops.queue_unlock = PV_CALLEE_SAVE(__pv_queue_unlock);
+
+ pv_lock_ops.wait = kvm_wait;
+ pv_lock_ops.kick = kvm_kick_cpu;
+#else
pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
pv_lock_ops.unlock_kick = kvm_unlock_kick;
+#endif
}
static __init int kvm_spinlock_init_jump(void)
Index: linux-2.6/kernel/Kconfig.locks
===================================================================
--- linux-2.6.orig/kernel/Kconfig.locks
+++ linux-2.6/kernel/Kconfig.locks
@@ -22...
2015 Feb 12
0
[PATCH V3] x86 spinlock: Fix memory corruption on completing completions
On 02/12, Raghavendra K T wrote:
>
> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
> * check again make sure it didn't become free while
> * we weren't looking.
> */
> - if (ACCESS_ONCE(lock->tickets.head) == want) {
> + head = ACCESS_ONCE(lock->tickets.head);
> + if (__tickets_equal(head, w...
2015 Feb 13
0
[PATCH V4] x86 spinlock: Fix memory corruption on completing completions
..._ticket_t)(tmp.tail - tmp.head) > TICKET_LOCK_INC
can be true because of TICKET_SLOWPATH_FLAG in .head, even if it is actually
unlocked. And the "(__ticket_t)" typecast looks unnecessary, it only adds more
confusuin, but this is cosmetic too.
> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
> * check again make sure it didn't become free while
> * we weren't looking.
> */
> - if (ACCESS_ONCE(lock->tickets.head) == want) {
> + head = READ_ONCE(lock->tickets.head);
> + if (__tickets_equal(head, wan...
2015 Feb 12
0
[PATCH V3] x86 spinlock: Fix memory corruption on completing completions
On 02/12, Raghavendra K T wrote:
>
> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
> * check again make sure it didn't become free while
> * we weren't looking.
> */
> - if (ACCESS_ONCE(lock->tickets.head) == want) {
> + head = ACCESS_ONCE(lock->tickets.head);
> + if (__tickets_equal(head, w...
2015 Feb 13
0
[PATCH V4] x86 spinlock: Fix memory corruption on completing completions
..._ticket_t)(tmp.tail - tmp.head) > TICKET_LOCK_INC
can be true because of TICKET_SLOWPATH_FLAG in .head, even if it is actually
unlocked. And the "(__ticket_t)" typecast looks unnecessary, it only adds more
confusuin, but this is cosmetic too.
> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
> * check again make sure it didn't become free while
> * we weren't looking.
> */
> - if (ACCESS_ONCE(lock->tickets.head) == want) {
> + head = READ_ONCE(lock->tickets.head);
> + if (__tickets_equal(head, wan...
2015 Feb 15
0
[PATCH V5] x86 spinlock: Fix memory corruption on completing completions
....c
@@ -609,7 +609,7 @@ static inline void check_zero(void)
u8 ret;
u8 old;
- old = ACCESS_ONCE(zero_stats);
+ old = READ_ONCE(zero_stats);
if (unlikely(old)) {
ret = cmpxchg(&zero_stats, old, 0);
/* This ensures only one fellow resets the stat */
@@ -727,6 +727,7 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
int cpu;
u64 start;
unsigned long flags;
+ __ticket_t head;
if (in_nmi())
return;
@@ -768,11 +769,15 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
*/
__ticket_enter_slowpath(lock);
+ /* make sure...
2014 Feb 26
0
[PATCH RFC v5 8/8] pvqspinlock, x86: Enable KVM to use qspinlock's PV support
...ck_ops to exploit KVM_FEATURE_PV_UNHALT if present.
@@ -807,8 +857,12 @@ void __init kvm_spinlock_init(void)
if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
return;
+#ifdef CONFIG_QUEUE_SPINLOCK
+ pv_lock_ops.kick_cpu = kvm_kick_cpu_type;
+#else
pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
pv_lock_ops.unlock_kick = kvm_unlock_kick;
+#endif
}
static __init int kvm_spinlock_init_jump(void)
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index f185584..a70fdeb 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -229,4 +229,4 @@ config ARCH_USE_QUEUE_SPIN...