[PATCH v1 03/11] KVM: arm64: Use guard()/scoped_guard() in arm64 KVM EL1 code
From: <hidden>
Date: 2026-06-12 06:59:31
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
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 <redacted>
---
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