KVM: Convert kvm_lock to raw_spinlock

PATCH Applied Jan Kiszka 2 participants 6 messages Feb 8, 2011 – Feb 9, 2011

Subsystems (3)

x86 KVM KVM x86

lore

Share & tools

lore

Jan Kiszka

author

2011-02-08 11:55 UTC #0 lore raw

PATCH 1/2 KVM: Convert kvm_lock to raw_spinlock

Code under this lock requires non-preemptibility. Ensure this also over -rt by converting it to raw spinlock.

Signed-off-by Jan Kiszka <[email protected]>

---
 arch/x86/include/asm/kvm_host.h |    2 +-
 arch/x86/kvm/mmu.c              |    4 ++--
 arch/x86/kvm/x86.c              |    4 ++--
 virt/kvm/kvm_main.c             |   36 ++++++++++++++++++------------------
 4 files changed, 23 insertions(+), 23 deletions(-)

arch/x86/include/asm/kvm_host.h +1 -1

index 25e7734..37bd730 100644
@@ -85,7 +85,7 @@
 
 #define ASYNC_PF_PER_VCPU 64
 
-extern spinlock_t kvm_lock;
+extern raw_spinlock_t kvm_lock;
 extern struct list_head vm_list;
 
 struct kvm_vcpu;

arch/x86/kvm/mmu.c +2 -2

index ccacf0b..b6a9963 100644
@@ -3587,7 +3587,7 @@ static int mmu_shrink(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
 	if (nr_to_scan == 0)
 		goto out;
 
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 
 	list_for_each_entry(kvm, &vm_list, vm_list) {
 		int idx, freed_pages;

@@ -3610,7 +3610,7 @@ static int mmu_shrink(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
 	if (kvm_freed)
 		list_move_tail(&kvm_freed->vm_list, &vm_list);
 
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 
 out:
 	return percpu_counter_read_positive(&kvm_total_used_mmu_pages);

arch/x86/kvm/x86.c +2 -2

index 36f54fb..ae6e75b 100644
@@ -4578,7 +4578,7 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
 
 	smp_call_function_single(freq->cpu, tsc_khz_changed, freq, 1);
 
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	list_for_each_entry(kvm, &vm_list, vm_list) {
 		kvm_for_each_vcpu(i, vcpu, kvm) {
 			if (vcpu->cpu != freq->cpu)

@@ -4588,7 +4588,7 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
 				send_ipi = 1;
 		}
 	}
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 
 	if (freq->old < freq->new && send_ipi) {
 		/*

virt/kvm/kvm_main.c +18 ~~-18~~

index 002fe0b..7b70c67 100644
@@ -69,7 +69,7 @@ MODULE_LICENSE("GPL");
  * 		kvm->lock --> kvm->slots_lock --> kvm->irq_lock
  */
 
-DEFINE_SPINLOCK(kvm_lock);
+DEFINE_RAW_SPINLOCK(kvm_lock);
 LIST_HEAD(vm_list);
 
 static cpumask_var_t cpus_hardware_enabled;

@@ -471,9 +471,9 @@ static struct kvm *kvm_create_vm(void)
 	mutex_init(&kvm->irq_lock);
 	mutex_init(&kvm->slots_lock);
 	atomic_set(&kvm->users_count, 1);
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	list_add(&kvm->vm_list, &vm_list);
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 
 	return kvm;

@@ -546,9 +546,9 @@ static void kvm_destroy_vm(struct kvm *kvm)
 	struct mm_struct *mm = kvm->mm;
 
 	kvm_arch_sync_events(kvm);
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	list_del(&kvm->vm_list);
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 	kvm_free_irq_routing(kvm);
 	for (i = 0; i < KVM_NR_BUSES; i++)
 		kvm_io_bus_destroy(kvm->buses[i]);

@@ -2130,9 +2130,9 @@ static void hardware_enable_nolock(void *junk)
 
 static void hardware_enable(void *junk)
 {
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	hardware_enable_nolock(junk);
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 }
 
 static void hardware_disable_nolock(void *junk)

@@ -2147,9 +2147,9 @@ static void hardware_disable_nolock(void *junk)
 
 static void hardware_disable(void *junk)
 {
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	hardware_disable_nolock(junk);
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 }
 
 static void hardware_disable_all_nolock(void)

@@ -2163,16 +2163,16 @@ static void hardware_disable_all_nolock(void)
 
 static void hardware_disable_all(void)
 {
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	hardware_disable_all_nolock();
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 }
 
 static int hardware_enable_all(void)
 {
 	int r = 0;
 
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 
 	kvm_usage_count++;
 	if (kvm_usage_count == 1) {

@@ -2185,7 +2185,7 @@ static int hardware_enable_all(void)
 		}
 	}
 
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 
 	return r;
 }

@@ -2347,10 +2347,10 @@ static int vm_stat_get(void *_offset, u64 *val)
 	struct kvm *kvm;
 
 	*val = 0;
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	list_for_each_entry(kvm, &vm_list, vm_list)
 		*val += *(u32 *)((void *)kvm + offset);
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 	return 0;
 }

@@ -2364,12 +2364,12 @@ static int vcpu_stat_get(void *_offset, u64 *val)
 	int i;
 
 	*val = 0;
-	spin_lock(&kvm_lock);
+	raw_spin_lock(&kvm_lock);
 	list_for_each_entry(kvm, &vm_list, vm_list)
 		kvm_for_each_vcpu(i, vcpu, kvm)
 			*val += *(u32 *)((void *)vcpu + offset);
 
-	spin_unlock(&kvm_lock);
+	raw_spin_unlock(&kvm_lock);
 	return 0;
 }

@@ -2410,7 +2410,7 @@ static int kvm_suspend(struct sys_device *dev, pm_message_t state)
 static int kvm_resume(struct sys_device *dev)
 {
 	if (kvm_usage_count) {
-		WARN_ON(spin_is_locked(&kvm_lock));
+		WARN_ON(raw_spin_is_locked(&kvm_lock));
 		hardware_enable_nolock(NULL);
 	}
 	return 0;

Signature · 1 line

1.7.1

Avi Kivity

2011-02-09 09:24 UTC #1 lore raw

Quoted 3 lines · Jan Kiszka

Code under this lock requires non-preemptibility. Ensure this also over -rt by converting it to raw spinlock.

Please add a code comment documenting what data under this lock requires it to be a raw spinlock.

Signature · 1 line

error compiling committee.c: too many arguments to function

Avi Kivity

2011-02-09 09:25 UTC #2 lore raw

Quoted 7 lines · Avi Kivity

Quoted 3 lines · Jan Kiszka
Code under this lock requires non-preemptibility. Ensure this also over -rt by converting it to raw spinlock.
Please add a code comment documenting what data under this lock requires it to be a raw spinlock.

Or better, put it in Documentation/kvm/locking.txt, which we'll try to grow to cover all locks.

Signature · 1 line

error compiling committee.c: too many arguments to function

Jan Kiszka

author

2011-02-09 12:31 UTC #3 lore raw

Quoted 6 lines · Avi Kivity

Quoted 5 lines · Avi Kivity
Quoted 3 lines · Jan Kiszka
Code under this lock requires non-preemptibility. Ensure this also over -rt by converting it to raw spinlock.

Quoted 7 lines

Quoted 3 lines
Please add a code comment documenting what data under this lock requires it to be a raw spinlock.
Or better, put it in Documentation/kvm/locking.txt, which we'll try to grow to cover all locks.

Something like

[Documentation/kvm/locking.txt]
KVM Lock Overview
-----------------

1. Spin locks

1.1 tsc_write_lock

Type: raw
Arch: x86
Protects: kvm_arch::{last_tsc_write,last_tsc_nsec,last_tsc_offset}
tsc offset in vmcb
Comment: 'raw' because updating the tsc offsets must not be preempted
...

Jan

Signature · 2 lines

Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Avi Kivity

2011-02-09 13:20 UTC #4 lore raw

Quoted 25 lines · Jan Kiszka

Quoted 6 lines · Avi Kivity
Quoted 5 lines · Avi Kivity
Quoted 3 lines · Jan Kiszka
Code under this lock requires non-preemptibility. Ensure this also over -rt by converting it to raw spinlock.
Quoted 7 lines
Quoted 3 lines
Please add a code comment documenting what data under this lock requires it to be a raw spinlock.
Or better, put it in Documentation/kvm/locking.txt, which we'll try to grow to cover all locks.
Something like
[Documentation/kvm/locking.txt]
KVM Lock Overview
-----------------
1. Spin locks
1.1 tsc_write_lock

Quoted 8 lines

Type: raw
Arch: x86
Protects: kvm_arch::{last_tsc_write,last_tsc_nsec,last_tsc_offset}
tsc offset in vmcb
Comment: 'raw' because updating the tsc offsets must not be preempted
...
?

Yes. I wouldn't sort them by type though, that changes from time to time.

Signature · 1 line

error compiling committee.c: too many arguments to function

Avi Kivity

Applied

2011-02-09 13:38 UTC #5 lore raw

In reply to Jan Kiszka

Quoted 3 lines · Jan Kiszka

Code under this lock requires non-preemptibility. Ensure this also over -rt by converting it to raw spinlock.

Applied, thanks.

Signature · 1 line

error compiling committee.c: too many arguments to function