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From: yhchen312@gmail.com
To: anup@brainfault.org
Cc: atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, bigeasy@linutronix.de,
	clrkwllms@kernel.org, rostedt@goodmis.org, kvm@vger.kernel.org,
	kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev,
	"Yuhang.chen" <yhchen312@gmail.com>,
	Quan Zhou <zhouquan@iscas.ac.cn>
Subject: [PATCH] RISC-V: KVM: Use raw_spinlock for VMID update critical section
Date: Thu, 16 Jul 2026 14:40:11 +0800	[thread overview]
Message-ID: <20260716064011.2387501-1-yhchen312@gmail.com> (raw)

From: "Yuhang.chen" <yhchen312@gmail.com>

The VMID update critical section performs an IPI broadcast via
on_each_cpu_mask() on VMID version rollover, which must not be preempted
under PREEMPT_RT. Convert vmid_lock to raw_spinlock_t and use plain
raw_spin_lock()/raw_spin_unlock() (interrupts stay enabled, since
on_each_cpu_mask() requires it).

Assisted-by: YuanSheng:deepseek-v4-pro
Co-developed-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Yuhang.chen <yhchen312@gmail.com>
---
 arch/riscv/kvm/vmid.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c
index c15bdb1dd8be..21c2b276b55d 100644
--- a/arch/riscv/kvm/vmid.c
+++ b/arch/riscv/kvm/vmid.c
@@ -21,7 +21,7 @@
 static unsigned long vmid_version = 1;
 static unsigned long vmid_next;
 static unsigned long vmid_bits __ro_after_init;
-static DEFINE_SPINLOCK(vmid_lock);
+static DEFINE_RAW_SPINLOCK(vmid_lock);
 
 void __init kvm_riscv_gstage_vmid_detect(void)
 {
@@ -78,14 +78,14 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 	if (!kvm_riscv_gstage_vmid_ver_changed(vmid))
 		return;
 
-	spin_lock(&vmid_lock);
+	raw_spin_lock(&vmid_lock);
 
 	/*
 	 * We need to re-check the vmid_version here to ensure that if
 	 * another vcpu already allocated a valid vmid for this vm.
 	 */
 	if (!kvm_riscv_gstage_vmid_ver_changed(vmid)) {
-		spin_unlock(&vmid_lock);
+		raw_spin_unlock(&vmid_lock);
 		return;
 	}
 
@@ -117,7 +117,7 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 
 	WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version));
 
-	spin_unlock(&vmid_lock);
+	raw_spin_unlock(&vmid_lock);
 
 	/* Request G-stage page table update for all VCPUs */
 	kvm_for_each_vcpu(i, v, vcpu->kvm)
-- 
2.34.1


WARNING: multiple messages have this Message-ID (diff)
From: yhchen312@gmail.com
To: anup@brainfault.org
Cc: atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, bigeasy@linutronix.de,
	clrkwllms@kernel.org, rostedt@goodmis.org, kvm@vger.kernel.org,
	kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev,
	"Yuhang.chen" <yhchen312@gmail.com>,
	Quan Zhou <zhouquan@iscas.ac.cn>
Subject: [PATCH] RISC-V: KVM: Use raw_spinlock for VMID update critical section
Date: Thu, 16 Jul 2026 14:40:11 +0800	[thread overview]
Message-ID: <20260716064011.2387501-1-yhchen312@gmail.com> (raw)

From: "Yuhang.chen" <yhchen312@gmail.com>

The VMID update critical section performs an IPI broadcast via
on_each_cpu_mask() on VMID version rollover, which must not be preempted
under PREEMPT_RT. Convert vmid_lock to raw_spinlock_t and use plain
raw_spin_lock()/raw_spin_unlock() (interrupts stay enabled, since
on_each_cpu_mask() requires it).

Assisted-by: YuanSheng:deepseek-v4-pro
Co-developed-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Yuhang.chen <yhchen312@gmail.com>
---
 arch/riscv/kvm/vmid.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c
index c15bdb1dd8be..21c2b276b55d 100644
--- a/arch/riscv/kvm/vmid.c
+++ b/arch/riscv/kvm/vmid.c
@@ -21,7 +21,7 @@
 static unsigned long vmid_version = 1;
 static unsigned long vmid_next;
 static unsigned long vmid_bits __ro_after_init;
-static DEFINE_SPINLOCK(vmid_lock);
+static DEFINE_RAW_SPINLOCK(vmid_lock);
 
 void __init kvm_riscv_gstage_vmid_detect(void)
 {
@@ -78,14 +78,14 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 	if (!kvm_riscv_gstage_vmid_ver_changed(vmid))
 		return;
 
-	spin_lock(&vmid_lock);
+	raw_spin_lock(&vmid_lock);
 
 	/*
 	 * We need to re-check the vmid_version here to ensure that if
 	 * another vcpu already allocated a valid vmid for this vm.
 	 */
 	if (!kvm_riscv_gstage_vmid_ver_changed(vmid)) {
-		spin_unlock(&vmid_lock);
+		raw_spin_unlock(&vmid_lock);
 		return;
 	}
 
@@ -117,7 +117,7 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 
 	WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version));
 
-	spin_unlock(&vmid_lock);
+	raw_spin_unlock(&vmid_lock);
 
 	/* Request G-stage page table update for all VCPUs */
 	kvm_for_each_vcpu(i, v, vcpu->kvm)
-- 
2.34.1


-- 
kvm-riscv mailing list
kvm-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kvm-riscv

WARNING: multiple messages have this Message-ID (diff)
From: yhchen312@gmail.com
To: anup@brainfault.org
Cc: atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, bigeasy@linutronix.de,
	clrkwllms@kernel.org, rostedt@goodmis.org, kvm@vger.kernel.org,
	kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev,
	"Yuhang.chen" <yhchen312@gmail.com>,
	Quan Zhou <zhouquan@iscas.ac.cn>
Subject: [PATCH] RISC-V: KVM: Use raw_spinlock for VMID update critical section
Date: Thu, 16 Jul 2026 14:40:11 +0800	[thread overview]
Message-ID: <20260716064011.2387501-1-yhchen312@gmail.com> (raw)

From: "Yuhang.chen" <yhchen312@gmail.com>

The VMID update critical section performs an IPI broadcast via
on_each_cpu_mask() on VMID version rollover, which must not be preempted
under PREEMPT_RT. Convert vmid_lock to raw_spinlock_t and use plain
raw_spin_lock()/raw_spin_unlock() (interrupts stay enabled, since
on_each_cpu_mask() requires it).

Assisted-by: YuanSheng:deepseek-v4-pro
Co-developed-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Signed-off-by: Yuhang.chen <yhchen312@gmail.com>
---
 arch/riscv/kvm/vmid.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c
index c15bdb1dd8be..21c2b276b55d 100644
--- a/arch/riscv/kvm/vmid.c
+++ b/arch/riscv/kvm/vmid.c
@@ -21,7 +21,7 @@
 static unsigned long vmid_version = 1;
 static unsigned long vmid_next;
 static unsigned long vmid_bits __ro_after_init;
-static DEFINE_SPINLOCK(vmid_lock);
+static DEFINE_RAW_SPINLOCK(vmid_lock);
 
 void __init kvm_riscv_gstage_vmid_detect(void)
 {
@@ -78,14 +78,14 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 	if (!kvm_riscv_gstage_vmid_ver_changed(vmid))
 		return;
 
-	spin_lock(&vmid_lock);
+	raw_spin_lock(&vmid_lock);
 
 	/*
 	 * We need to re-check the vmid_version here to ensure that if
 	 * another vcpu already allocated a valid vmid for this vm.
 	 */
 	if (!kvm_riscv_gstage_vmid_ver_changed(vmid)) {
-		spin_unlock(&vmid_lock);
+		raw_spin_unlock(&vmid_lock);
 		return;
 	}
 
@@ -117,7 +117,7 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 
 	WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version));
 
-	spin_unlock(&vmid_lock);
+	raw_spin_unlock(&vmid_lock);
 
 	/* Request G-stage page table update for all VCPUs */
 	kvm_for_each_vcpu(i, v, vcpu->kvm)
-- 
2.34.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

             reply	other threads:[~2026-07-16  6:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-16  6:40 yhchen312 [this message]
2026-07-16  6:40 ` [PATCH] RISC-V: KVM: Use raw_spinlock for VMID update critical section yhchen312
2026-07-16  6:40 ` yhchen312
2026-07-16  6:57 ` sashiko-bot

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