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linux/debian/patches/bugfix/x86/itlb_multihit/0011-kvm-Convert-kvm_lock-t...

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From: Junaid Shahid <junaids@google.com>
Date: Thu, 3 Jan 2019 17:14:28 -0800
Subject: kvm: Convert kvm_lock to a mutex
commit 0d9ce162cf46c99628cc5da9510b959c7976735b upstream.
It doesn't seem as if there is any particular need for kvm_lock to be a
spinlock, so convert the lock to a mutex so that sleepable functions (in
particular cond_resched()) can be called while holding it.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 4.19: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
Documentation/virtual/kvm/locking.txt | 4 +---
arch/s390/kvm/kvm-s390.c | 4 ++--
arch/x86/kvm/mmu.c | 4 ++--
arch/x86/kvm/x86.c | 14 ++++++-------
include/linux/kvm_host.h | 2 +-
virt/kvm/kvm_main.c | 30 +++++++++++++--------------
6 files changed, 28 insertions(+), 30 deletions(-)
--- a/Documentation/virtual/kvm/locking.txt
+++ b/Documentation/virtual/kvm/locking.txt
@@ -15,8 +15,6 @@ The acquisition orders for mutexes are a
On x86, vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock.
-For spinlocks, kvm_lock is taken outside kvm->mmu_lock.
-
Everything else is a leaf: no other lock is taken inside the critical
sections.
@@ -169,7 +167,7 @@ which time it will be set using the Dirt
------------
Name: kvm_lock
-Type: spinlock_t
+Type: mutex
Arch: any
Protects: - vm_list
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2108,13 +2108,13 @@ int kvm_arch_init_vm(struct kvm *kvm, un
kvm->arch.sca = (struct bsca_block *) get_zeroed_page(alloc_flags);
if (!kvm->arch.sca)
goto out_err;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
sca_offset += 16;
if (sca_offset + sizeof(struct bsca_block) > PAGE_SIZE)
sca_offset = 0;
kvm->arch.sca = (struct bsca_block *)
((char *) kvm->arch.sca + sca_offset);
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
sprintf(debug_name, "kvm-%u", current->pid);
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5819,7 +5819,7 @@ mmu_shrink_scan(struct shrinker *shrink,
int nr_to_scan = sc->nr_to_scan;
unsigned long freed = 0;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
int idx;
@@ -5869,7 +5869,7 @@ unlock:
break;
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
return freed;
}
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6490,7 +6490,7 @@ static void kvm_hyperv_tsc_notifier(void
struct kvm_vcpu *vcpu;
int cpu;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list)
kvm_make_mclock_inprogress_request(kvm);
@@ -6516,7 +6516,7 @@ static void kvm_hyperv_tsc_notifier(void
spin_unlock(&ka->pvclock_gtod_sync_lock);
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
}
#endif
@@ -6574,17 +6574,17 @@ static int kvmclock_cpufreq_notifier(str
smp_call_function_single(freq->cpu, tsc_khz_changed, freq, 1);
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
kvm_for_each_vcpu(i, vcpu, kvm) {
if (vcpu->cpu != freq->cpu)
continue;
kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
- if (vcpu->cpu != smp_processor_id())
+ if (vcpu->cpu != raw_smp_processor_id())
send_ipi = 1;
}
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
if (freq->old < freq->new && send_ipi) {
/*
@@ -6710,12 +6710,12 @@ static void pvclock_gtod_update_fn(struc
struct kvm_vcpu *vcpu;
int i;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list)
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
atomic_set(&kvm_guest_has_master_clock, 0);
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
}
static DECLARE_WORK(pvclock_gtod_work, pvclock_gtod_update_fn);
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -141,7 +141,7 @@ static inline bool is_error_page(struct
extern struct kmem_cache *kvm_vcpu_cache;
-extern spinlock_t kvm_lock;
+extern struct mutex kvm_lock;
extern struct list_head vm_list;
struct kvm_io_range {
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -92,7 +92,7 @@ EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
* kvm->lock --> kvm->slots_lock --> kvm->irq_lock
*/
-DEFINE_SPINLOCK(kvm_lock);
+DEFINE_MUTEX(kvm_lock);
static DEFINE_RAW_SPINLOCK(kvm_count_lock);
LIST_HEAD(vm_list);
@@ -684,9 +684,9 @@ static struct kvm *kvm_create_vm(unsigne
if (r)
goto out_err;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
preempt_notifier_inc();
@@ -732,9 +732,9 @@ static void kvm_destroy_vm(struct kvm *k
kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
kvm_destroy_vm_debugfs(kvm);
kvm_arch_sync_events(kvm);
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_del(&kvm->vm_list);
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
kvm_free_irq_routing(kvm);
for (i = 0; i < KVM_NR_BUSES; i++) {
struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
@@ -3828,13 +3828,13 @@ static int vm_stat_get(void *_offset, u6
u64 tmp_val;
*val = 0;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
stat_tmp.kvm = kvm;
vm_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
*val += tmp_val;
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
return 0;
}
@@ -3847,12 +3847,12 @@ static int vm_stat_clear(void *_offset,
if (val)
return -EINVAL;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
stat_tmp.kvm = kvm;
vm_stat_clear_per_vm((void *)&stat_tmp, 0);
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
return 0;
}
@@ -3867,13 +3867,13 @@ static int vcpu_stat_get(void *_offset,
u64 tmp_val;
*val = 0;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
stat_tmp.kvm = kvm;
vcpu_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
*val += tmp_val;
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
return 0;
}
@@ -3886,12 +3886,12 @@ static int vcpu_stat_clear(void *_offset
if (val)
return -EINVAL;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
stat_tmp.kvm = kvm;
vcpu_stat_clear_per_vm((void *)&stat_tmp, 0);
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
return 0;
}
@@ -3912,7 +3912,7 @@ static void kvm_uevent_notify_change(uns
if (!kvm_dev.this_device || !kvm)
return;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
if (type == KVM_EVENT_CREATE_VM) {
kvm_createvm_count++;
kvm_active_vms++;
@@ -3921,7 +3921,7 @@ static void kvm_uevent_notify_change(uns
}
created = kvm_createvm_count;
active = kvm_active_vms;
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
env = kzalloc(sizeof(*env), GFP_KERNEL);
if (!env)
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