[PATCH v1 03/11] KVM: arm64: Use guard()/scoped_guard() in arm64 KVM EL1 code
tabba at google.com
tabba at google.com
Thu Jun 11 23:59:17 PDT 2026
Convert the manual mutex_lock()/spin_lock() pairs in
arch/arm64/kvm/{pkvm,arm,mmu,reset,psci}.c to guard(mutex),
guard(spinlock) and scoped_guard(), dropping unlock-only goto labels in
favour of direct returns. Centralised cleanup gotos that still serve
other resources are preserved.
reset.c uses scoped_guard() rather than guard() so the lock covers only
the small read/update window inside kvm_reset_vcpu(), leaving the rest
of the function outside the critical section.
Signed-off-by: Fuad Tabba <tabba at google.com>
---
arch/arm64/kvm/arm.c | 14 +++-----
arch/arm64/kvm/mmu.c | 80 +++++++++++++++---------------------------
arch/arm64/kvm/pkvm.c | 26 ++++++--------
arch/arm64/kvm/psci.c | 17 ++++-----
arch/arm64/kvm/reset.c | 8 ++---
5 files changed, 53 insertions(+), 92 deletions(-)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 9453321ef8c6..c9f36932c980 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -793,9 +793,7 @@ int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state)
{
- int ret = 0;
-
- spin_lock(&vcpu->arch.mp_state_lock);
+ guard(spinlock)(&vcpu->arch.mp_state_lock);
switch (mp_state->mp_state) {
case KVM_MP_STATE_RUNNABLE:
@@ -808,12 +806,10 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
kvm_arm_vcpu_suspend(vcpu);
break;
default:
- ret = -EINVAL;
+ return -EINVAL;
}
- spin_unlock(&vcpu->arch.mp_state_lock);
-
- return ret;
+ return 0;
}
/**
@@ -1726,15 +1722,13 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
/*
* Handle the "start in power-off" case.
*/
- spin_lock(&vcpu->arch.mp_state_lock);
+ guard(spinlock)(&vcpu->arch.mp_state_lock);
if (power_off)
__kvm_arm_vcpu_power_off(vcpu);
else
WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE);
- spin_unlock(&vcpu->arch.mp_state_lock);
-
return 0;
}
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 4da9281312eb..d18f4ce7ceae 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -391,13 +391,13 @@ static void stage2_flush_vm(struct kvm *kvm)
*/
void __init free_hyp_pgds(void)
{
- mutex_lock(&kvm_hyp_pgd_mutex);
- if (hyp_pgtable) {
- kvm_pgtable_hyp_destroy(hyp_pgtable);
- kfree(hyp_pgtable);
- hyp_pgtable = NULL;
- }
- mutex_unlock(&kvm_hyp_pgd_mutex);
+ guard(mutex)(&kvm_hyp_pgd_mutex);
+ if (!hyp_pgtable)
+ return;
+
+ kvm_pgtable_hyp_destroy(hyp_pgtable);
+ kfree(hyp_pgtable);
+ hyp_pgtable = NULL;
}
static bool kvm_host_owns_hyp_mappings(void)
@@ -424,16 +424,11 @@ static bool kvm_host_owns_hyp_mappings(void)
int __create_hyp_mappings(unsigned long start, unsigned long size,
unsigned long phys, enum kvm_pgtable_prot prot)
{
- int err;
-
if (WARN_ON(!kvm_host_owns_hyp_mappings()))
return -EINVAL;
- mutex_lock(&kvm_hyp_pgd_mutex);
- err = kvm_pgtable_hyp_map(hyp_pgtable, start, size, phys, prot);
- mutex_unlock(&kvm_hyp_pgd_mutex);
-
- return err;
+ guard(mutex)(&kvm_hyp_pgd_mutex);
+ return kvm_pgtable_hyp_map(hyp_pgtable, start, size, phys, prot);
}
static phys_addr_t kvm_kaddr_to_phys(void *kaddr)
@@ -481,56 +476,42 @@ static int share_pfn_hyp(u64 pfn)
{
struct rb_node **node, *parent;
struct hyp_shared_pfn *this;
- int ret = 0;
- mutex_lock(&hyp_shared_pfns_lock);
+ guard(mutex)(&hyp_shared_pfns_lock);
this = find_shared_pfn(pfn, &node, &parent);
if (this) {
this->count++;
- goto unlock;
+ return 0;
}
this = kzalloc_obj(*this);
- if (!this) {
- ret = -ENOMEM;
- goto unlock;
- }
+ if (!this)
+ return -ENOMEM;
this->pfn = pfn;
this->count = 1;
rb_link_node(&this->node, parent, node);
rb_insert_color(&this->node, &hyp_shared_pfns);
- ret = kvm_call_hyp_nvhe(__pkvm_host_share_hyp, pfn);
-unlock:
- mutex_unlock(&hyp_shared_pfns_lock);
-
- return ret;
+ return kvm_call_hyp_nvhe(__pkvm_host_share_hyp, pfn);
}
static int unshare_pfn_hyp(u64 pfn)
{
struct rb_node **node, *parent;
struct hyp_shared_pfn *this;
- int ret = 0;
- mutex_lock(&hyp_shared_pfns_lock);
+ guard(mutex)(&hyp_shared_pfns_lock);
this = find_shared_pfn(pfn, &node, &parent);
- if (WARN_ON(!this)) {
- ret = -ENOENT;
- goto unlock;
- }
+ if (WARN_ON(!this))
+ return -ENOENT;
this->count--;
if (this->count)
- goto unlock;
+ return 0;
rb_erase(&this->node, &hyp_shared_pfns);
kfree(this);
- ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_hyp, pfn);
-unlock:
- mutex_unlock(&hyp_shared_pfns_lock);
-
- return ret;
+ return kvm_call_hyp_nvhe(__pkvm_host_unshare_hyp, pfn);
}
int kvm_share_hyp(void *from, void *to)
@@ -655,7 +636,7 @@ int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
unsigned long base;
int ret = 0;
- mutex_lock(&kvm_hyp_pgd_mutex);
+ guard(mutex)(&kvm_hyp_pgd_mutex);
/*
* This assumes that we have enough space below the idmap
@@ -670,8 +651,6 @@ int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
base = io_map_base - size;
ret = __hyp_alloc_private_va_range(base);
- mutex_unlock(&kvm_hyp_pgd_mutex);
-
if (!ret)
*haddr = base;
@@ -714,17 +693,16 @@ int create_hyp_stack(phys_addr_t phys_addr, unsigned long *haddr)
size_t size;
int ret;
- mutex_lock(&kvm_hyp_pgd_mutex);
- /*
- * Efficient stack verification using the NVHE_STACK_SHIFT bit implies
- * an alignment of our allocation on the order of the size.
- */
- size = NVHE_STACK_SIZE * 2;
- base = ALIGN_DOWN(io_map_base - size, size);
+ scoped_guard(mutex, &kvm_hyp_pgd_mutex) {
+ /*
+ * Efficient stack verification using the NVHE_STACK_SHIFT bit implies
+ * an alignment of our allocation on the order of the size.
+ */
+ size = NVHE_STACK_SIZE * 2;
+ base = ALIGN_DOWN(io_map_base - size, size);
- ret = __hyp_alloc_private_va_range(base);
-
- mutex_unlock(&kvm_hyp_pgd_mutex);
+ ret = __hyp_alloc_private_va_range(base);
+ }
if (ret) {
kvm_err("Cannot allocate hyp stack guard page\n");
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 053e4f733e4b..a39111b70f9f 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -190,39 +190,33 @@ bool pkvm_hyp_vm_is_created(struct kvm *kvm)
int pkvm_create_hyp_vm(struct kvm *kvm)
{
- int ret = 0;
-
/*
* Synchronise with kvm_arch_prepare_memory_region(), as we
* prevent memslot modifications on a pVM that has been run.
*/
- mutex_lock(&kvm->slots_lock);
- mutex_lock(&kvm->arch.config_lock);
- if (!pkvm_hyp_vm_is_created(kvm))
- ret = __pkvm_create_hyp_vm(kvm);
- mutex_unlock(&kvm->arch.config_lock);
- mutex_unlock(&kvm->slots_lock);
+ guard(mutex)(&kvm->slots_lock);
+ guard(mutex)(&kvm->arch.config_lock);
- return ret;
+ if (!pkvm_hyp_vm_is_created(kvm))
+ return __pkvm_create_hyp_vm(kvm);
+
+ return 0;
}
int pkvm_create_hyp_vcpu(struct kvm_vcpu *vcpu)
{
- int ret = 0;
+ guard(mutex)(&vcpu->kvm->arch.config_lock);
- mutex_lock(&vcpu->kvm->arch.config_lock);
if (!vcpu_get_flag(vcpu, VCPU_PKVM_FINALIZED))
- ret = __pkvm_create_hyp_vcpu(vcpu);
- mutex_unlock(&vcpu->kvm->arch.config_lock);
+ return __pkvm_create_hyp_vcpu(vcpu);
- return ret;
+ return 0;
}
void pkvm_destroy_hyp_vm(struct kvm *kvm)
{
- mutex_lock(&kvm->arch.config_lock);
+ guard(mutex)(&kvm->arch.config_lock);
__pkvm_destroy_hyp_vm(kvm);
- mutex_unlock(&kvm->arch.config_lock);
}
int pkvm_init_host_vm(struct kvm *kvm, unsigned long type)
diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index 3b5dbe9a0a0e..e1389c525e9d 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -62,7 +62,6 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
struct vcpu_reset_state *reset_state;
struct kvm *kvm = source_vcpu->kvm;
struct kvm_vcpu *vcpu = NULL;
- int ret = PSCI_RET_SUCCESS;
unsigned long cpu_id;
cpu_id = smccc_get_arg1(source_vcpu);
@@ -78,14 +77,13 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
if (!vcpu)
return PSCI_RET_INVALID_PARAMS;
- spin_lock(&vcpu->arch.mp_state_lock);
+ guard(spinlock)(&vcpu->arch.mp_state_lock);
+
if (!kvm_arm_vcpu_stopped(vcpu)) {
if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
- ret = PSCI_RET_ALREADY_ON;
+ return PSCI_RET_ALREADY_ON;
else
- ret = PSCI_RET_INVALID_PARAMS;
-
- goto out_unlock;
+ return PSCI_RET_INVALID_PARAMS;
}
reset_state = &vcpu->arch.reset_state;
@@ -113,9 +111,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE);
kvm_vcpu_wake_up(vcpu);
-out_unlock:
- spin_unlock(&vcpu->arch.mp_state_lock);
- return ret;
+ return PSCI_RET_SUCCESS;
}
static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
@@ -176,9 +172,8 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
* re-initialized.
*/
kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
- spin_lock(&tmp->arch.mp_state_lock);
+ guard(spinlock)(&tmp->arch.mp_state_lock);
WRITE_ONCE(tmp->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED);
- spin_unlock(&tmp->arch.mp_state_lock);
}
kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index b963fd975aac..60969d90bdd3 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -193,10 +193,10 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
bool loaded;
u32 pstate;
- spin_lock(&vcpu->arch.mp_state_lock);
- reset_state = vcpu->arch.reset_state;
- vcpu->arch.reset_state.reset = false;
- spin_unlock(&vcpu->arch.mp_state_lock);
+ scoped_guard(spinlock, &vcpu->arch.mp_state_lock) {
+ reset_state = vcpu->arch.reset_state;
+ vcpu->arch.reset_state.reset = false;
+ }
preempt_disable();
loaded = (vcpu->cpu != -1);
--
2.54.0.1136.gdb2ca164c4-goog
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