linux-kernel - [PATCH v4 3/5] RISC-V: KVM: switch to kvm_trylock/unlock_all

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Message-ID: <20250430203013.366479-4-mlevitsk@redhat.com>
Date: Wed, 30 Apr 2025 16:30:11 -0400
From: Maxim Levitsky <mlevitsk@...hat.com>
To: kvm@...r.kernel.org
Cc: linux-riscv@...ts.infradead.org,
	Kunkun Jiang <jiangkunkun@...wei.com>,
	Waiman Long <longman@...hat.com>,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Catalin Marinas <catalin.marinas@....com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Borislav Petkov <bp@...en8.de>,
	Albert Ou <aou@...s.berkeley.edu>,
	Anup Patel <anup@...infault.org>,
	Paul Walmsley <paul.walmsley@...ive.com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Alexandre Ghiti <alex@...ti.fr>,
	Alexander Potapenko <glider@...gle.com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Andre Przywara <andre.przywara@....com>,
	x86@...nel.org,
	Joey Gouly <joey.gouly@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	kvm-riscv@...ts.infradead.org,
	Atish Patra <atishp@...shpatra.org>,
	Ingo Molnar <mingo@...hat.com>,
	Jing Zhang <jingzhangos@...gle.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	kvmarm@...ts.linux.dev,
	Will Deacon <will@...nel.org>,
	Keisuke Nishimura <keisuke.nishimura@...ia.fr>,
	Sebastian Ott <sebott@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Shusen Li <lishusen2@...wei.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Marc Zyngier <maz@...nel.org>,
	Maxim Levitsky <mlevitsk@...hat.com>,
	Sean Christopherson <seanjc@...gle.com>,
	Zenghui Yu <yuzenghui@...wei.com>
Subject: [PATCH v4 3/5] RISC-V: KVM: switch to kvm_trylock/unlock_all_vcpus

Use the kvm_trylock_all_vcpus()/unlock_all_vcpus() instead of riscv's own
implementation, to avoid triggering a lockdep warning,
if the VM is configured to have more than MAX_LOCK_DEPTH vCPUs.

Compile tested only.

Suggested-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 arch/riscv/kvm/aia_device.c | 34 ++--------------------------------
 1 file changed, 2 insertions(+), 32 deletions(-)

diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
index 39cd26af5a69..6315821f0d69 100644
--- a/arch/riscv/kvm/aia_device.c
+++ b/arch/riscv/kvm/aia_device.c
@@ -12,36 +12,6 @@
 #include <linux/kvm_host.h>
 #include <linux/uaccess.h>
 
-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);
-	}
-}
-
-static void unlock_all_vcpus(struct kvm *kvm)
-{
-	unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
-}
-
-static bool lock_all_vcpus(struct kvm *kvm)
-{
-	struct kvm_vcpu *tmp_vcpu;
-	unsigned long c;
-
-	kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
-		if (!mutex_trylock(&tmp_vcpu->mutex)) {
-			unlock_vcpus(kvm, c - 1);
-			return false;
-		}
-	}
-
-	return true;
-}
-
 static int aia_create(struct kvm_device *dev, u32 type)
 {
 	int ret;
@@ -53,7 +23,7 @@ static int aia_create(struct kvm_device *dev, u32 type)
 		return -EEXIST;
 
 	ret = -EBUSY;
-	if (!lock_all_vcpus(kvm))
+	if (kvm_trylock_all_vcpus(kvm))
 		return ret;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
@@ -65,7 +35,7 @@ static int aia_create(struct kvm_device *dev, u32 type)
 	kvm->arch.aia.in_kernel = true;
 
 out_unlock:
-	unlock_all_vcpus(kvm);
+	kvm_unlock_all_vcpus(kvm);
 	return ret;
 }
 
-- 
2.46.0