From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: Alexander Potapenko <glider@google.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
kvm-riscv@lists.infradead.org,
Oliver Upton <oliver.upton@linux.dev>,
Dave Hansen <dave.hansen@linux.intel.com>,
Jing Zhang <jingzhangos@google.com>,
Waiman Long <longman@redhat.com>,
x86@kernel.org, Kunkun Jiang <jiangkunkun@huawei.com>,
Boqun Feng <boqun.feng@gmail.com>,
Anup Patel <anup@brainfault.org>,
Albert Ou <aou@eecs.berkeley.edu>,
kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org,
Zenghui Yu <yuzenghui@huawei.com>, Borislav Petkov <bp@alien8.de>,
Alexandre Ghiti <alex@ghiti.fr>,
Keisuke Nishimura <keisuke.nishimura@inria.fr>,
Sebastian Ott <sebott@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Atish Patra <atishp@atishpatra.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Randy Dunlap <rdunlap@infradead.org>,
Will Deacon <will@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
linux-riscv@lists.infradead.org, Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Joey Gouly <joey.gouly@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Andre Przywara <andre.przywara@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sean Christopherson <seanjc@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>
Subject: [PATCH v2 3/4] KVM: arm64: switch to using kvm_lock/unlock_all_vcpus
Date: Tue, 8 Apr 2025 21:41:35 -0400 [thread overview]
Message-ID: <20250409014136.2816971-4-mlevitsk@redhat.com> (raw)
In-Reply-To: <20250409014136.2816971-1-mlevitsk@redhat.com>
Switch to kvm_lock/unlock_all_vcpus instead of arm's own
version.
This fixes lockdep warning about reaching maximum lock depth:
[ 328.171264] BUG: MAX_LOCK_DEPTH too low!
[ 328.175227] turning off the locking correctness validator.
[ 328.180726] Please attach the output of /proc/lock_stat to the bug report
[ 328.187531] depth: 48 max: 48!
[ 328.190678] 48 locks held by qemu-kvm/11664:
[ 328.194957] #0: ffff800086de5ba0 (&kvm->lock){+.+.}-{3:3}, at: kvm_ioctl_create_device+0x174/0x5b0
[ 328.204048] #1: ffff0800e78800b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.212521] #2: ffff07ffeee51e98 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.220991] #3: ffff0800dc7d80b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.229463] #4: ffff07ffe0c980b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.237934] #5: ffff0800a3883c78 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.246405] #6: ffff07fffbe480b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/arm64/include/asm/kvm_host.h | 3 --
arch/arm64/kvm/arch_timer.c | 4 +--
arch/arm64/kvm/arm.c | 43 ---------------------------
arch/arm64/kvm/vgic/vgic-init.c | 4 +--
arch/arm64/kvm/vgic/vgic-its.c | 8 ++---
arch/arm64/kvm/vgic/vgic-kvm-device.c | 12 ++++----
6 files changed, 14 insertions(+), 60 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e98cfe7855a6..96ce0b01a61e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1263,9 +1263,6 @@ int __init populate_sysreg_config(const struct sys_reg_desc *sr,
unsigned int idx);
int __init populate_nv_trap_config(void);
-bool lock_all_vcpus(struct kvm *kvm);
-void unlock_all_vcpus(struct kvm *kvm);
-
void kvm_calculate_traps(struct kvm_vcpu *vcpu);
/* MMIO helpers */
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 5133dcbfe9f7..1c71ce9a5e73 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1766,7 +1766,7 @@ int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm,
mutex_lock(&kvm->lock);
- if (lock_all_vcpus(kvm)) {
+ if (!kvm_lock_all_vcpus(kvm, true)) {
set_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &kvm->arch.flags);
/*
@@ -1778,7 +1778,7 @@ int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm,
kvm->arch.timer_data.voffset = offset->counter_offset;
kvm->arch.timer_data.poffset = offset->counter_offset;
- unlock_all_vcpus(kvm);
+ kvm_unlock_all_vcpus(kvm);
} else {
ret = -EBUSY;
}
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 68fec8c95fee..d31f42a71bdc 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1914,49 +1914,6 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
}
}
-/* unlocks vcpus from @vcpu_lock_idx and smaller */
-static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
-{
- struct kvm_vcpu *tmp_vcpu;
-
- for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
- tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
- mutex_unlock(&tmp_vcpu->mutex);
- }
-}
-
-void unlock_all_vcpus(struct kvm *kvm)
-{
- lockdep_assert_held(&kvm->lock);
-
- unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
-}
-
-/* Returns true if all vcpus were locked, false otherwise */
-bool lock_all_vcpus(struct kvm *kvm)
-{
- struct kvm_vcpu *tmp_vcpu;
- unsigned long c;
-
- lockdep_assert_held(&kvm->lock);
-
- /*
- * Any time a vcpu is in an ioctl (including running), the
- * core KVM code tries to grab the vcpu->mutex.
- *
- * By grabbing the vcpu->mutex of all VCPUs we ensure that no
- * other VCPUs can fiddle with the state while we access it.
- */
- kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
- if (!mutex_trylock(&tmp_vcpu->mutex)) {
- unlock_vcpus(kvm, c - 1);
- return false;
- }
- }
-
- return true;
-}
-
static unsigned long nvhe_percpu_size(void)
{
return (unsigned long)CHOOSE_NVHE_SYM(__per_cpu_end) -
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 1f33e71c2a73..8241a57e3f96 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -88,7 +88,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
lockdep_assert_held(&kvm->lock);
ret = -EBUSY;
- if (!lock_all_vcpus(kvm))
+ if (kvm_lock_all_vcpus(kvm, true))
return ret;
mutex_lock(&kvm->arch.config_lock);
@@ -142,7 +142,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
out_unlock:
mutex_unlock(&kvm->arch.config_lock);
- unlock_all_vcpus(kvm);
+ kvm_unlock_all_vcpus(kvm);
return ret;
}
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index fb96802799c6..a06d554cb8a2 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -1999,7 +1999,7 @@ static int vgic_its_attr_regs_access(struct kvm_device *dev,
mutex_lock(&dev->kvm->lock);
- if (!lock_all_vcpus(dev->kvm)) {
+ if (kvm_lock_all_vcpus(dev->kvm, true)) {
mutex_unlock(&dev->kvm->lock);
return -EBUSY;
}
@@ -2034,7 +2034,7 @@ static int vgic_its_attr_regs_access(struct kvm_device *dev,
}
out:
mutex_unlock(&dev->kvm->arch.config_lock);
- unlock_all_vcpus(dev->kvm);
+ kvm_unlock_all_vcpus(dev->kvm);
mutex_unlock(&dev->kvm->lock);
return ret;
}
@@ -2704,7 +2704,7 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr)
mutex_lock(&kvm->lock);
- if (!lock_all_vcpus(kvm)) {
+ if (kvm_lock_all_vcpus(kvm, true)) {
mutex_unlock(&kvm->lock);
return -EBUSY;
}
@@ -2726,7 +2726,7 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr)
mutex_unlock(&its->its_lock);
mutex_unlock(&kvm->arch.config_lock);
- unlock_all_vcpus(kvm);
+ kvm_unlock_all_vcpus(kvm);
mutex_unlock(&kvm->lock);
return ret;
}
diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index 359094f68c23..232838891464 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -268,7 +268,7 @@ static int vgic_set_common_attr(struct kvm_device *dev,
return -ENXIO;
mutex_lock(&dev->kvm->lock);
- if (!lock_all_vcpus(dev->kvm)) {
+ if (kvm_lock_all_vcpus(dev->kvm, true)) {
mutex_unlock(&dev->kvm->lock);
return -EBUSY;
}
@@ -276,7 +276,7 @@ static int vgic_set_common_attr(struct kvm_device *dev,
mutex_lock(&dev->kvm->arch.config_lock);
r = vgic_v3_save_pending_tables(dev->kvm);
mutex_unlock(&dev->kvm->arch.config_lock);
- unlock_all_vcpus(dev->kvm);
+ kvm_unlock_all_vcpus(dev->kvm);
mutex_unlock(&dev->kvm->lock);
return r;
}
@@ -390,7 +390,7 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
mutex_lock(&dev->kvm->lock);
- if (!lock_all_vcpus(dev->kvm)) {
+ if (kvm_lock_all_vcpus(dev->kvm, true)) {
mutex_unlock(&dev->kvm->lock);
return -EBUSY;
}
@@ -415,7 +415,7 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
out:
mutex_unlock(&dev->kvm->arch.config_lock);
- unlock_all_vcpus(dev->kvm);
+ kvm_unlock_all_vcpus(dev->kvm);
mutex_unlock(&dev->kvm->lock);
if (!ret && !is_write)
@@ -554,7 +554,7 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
mutex_lock(&dev->kvm->lock);
- if (!lock_all_vcpus(dev->kvm)) {
+ if (kvm_lock_all_vcpus(dev->kvm, true)) {
mutex_unlock(&dev->kvm->lock);
return -EBUSY;
}
@@ -611,7 +611,7 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
out:
mutex_unlock(&dev->kvm->arch.config_lock);
- unlock_all_vcpus(dev->kvm);
+ kvm_unlock_all_vcpus(dev->kvm);
mutex_unlock(&dev->kvm->lock);
if (!ret && uaccess && !is_write) {
--
2.26.3
--
kvm-riscv mailing list
kvm-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kvm-riscv
next prev parent reply other threads:[~2025-04-09 1:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-09 1:41 [PATCH v2 0/4] KVM: extract lock_all_vcpus/unlock_all_vcpus Maxim Levitsky
2025-04-09 1:41 ` [PATCH v2 1/4] locking/mutex: implement mutex_trylock_nested Maxim Levitsky
2025-04-10 8:04 ` Peter Zijlstra
2025-04-09 1:41 ` [PATCH v2 2/4] KVM: x86: move sev_lock/unlock_vcpus_for_migration to kvm_main.c Maxim Levitsky
2025-04-09 13:47 ` Waiman Long
2025-04-09 20:45 ` Oliver Upton
2025-04-10 8:16 ` Peter Zijlstra
2025-04-16 17:48 ` Paolo Bonzini
2025-04-16 18:50 ` Peter Zijlstra
2025-04-17 9:53 ` Paolo Bonzini
2025-04-09 1:41 ` Maxim Levitsky [this message]
2025-04-09 1:41 ` [PATCH v2 4/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus Maxim Levitsky
2025-04-09 19:53 ` [PATCH v2 0/4] KVM: extract lock_all_vcpus/unlock_all_vcpus Sean Christopherson
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