From: Bibo Mao <maobibo@loongson.cn>
To: Huacai Chen <chenhuacai@kernel.org>,
Xianglai Li <lixianglai@loongson.cn>
Cc: WANG Xuerui <kernel@xen0n.name>,
kvm@vger.kernel.org, loongarch@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] LoongArch: KVM: Avoid use copy_from_user with lock hold in kvm_eiointc_sw_status_access
Date: Tue, 2 Sep 2025 17:49:43 +0800 [thread overview]
Message-ID: <20250902094945.2957566-3-maobibo@loongson.cn> (raw)
In-Reply-To: <20250902094945.2957566-1-maobibo@loongson.cn>
Function copy_from_user() and copy_to_user() may sleep because of page
fault, and they cannot be called in spin_lock hold context. Here move
funtcion calling with copy_from_user() and copy_to_user() out of function
kvm_eiointc_sw_status_access().
Fixes: 1ad7efa552fd5 ("LoongArch: KVM: Add EIOINTC user mode read and write functions")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
arch/loongarch/kvm/intc/eiointc.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/arch/loongarch/kvm/intc/eiointc.c b/arch/loongarch/kvm/intc/eiointc.c
index 2fb5b9c6e8ad..dd0477faf8e0 100644
--- a/arch/loongarch/kvm/intc/eiointc.c
+++ b/arch/loongarch/kvm/intc/eiointc.c
@@ -522,19 +522,17 @@ static int kvm_eiointc_regs_access(struct kvm_device *dev,
static int kvm_eiointc_sw_status_access(struct kvm_device *dev,
struct kvm_device_attr *attr,
- bool is_write)
+ bool is_write, int *data)
{
int addr, ret = 0;
unsigned long flags;
void *p = NULL;
- void __user *data;
struct loongarch_eiointc *s;
s = dev->kvm->arch.eiointc;
addr = attr->attr;
addr &= 0xffff;
- data = (void __user *)attr->addr;
switch (addr) {
case KVM_DEV_LOONGARCH_EXTIOI_SW_STATUS_NUM_CPU:
if (is_write)
@@ -556,13 +554,10 @@ static int kvm_eiointc_sw_status_access(struct kvm_device *dev,
return -EINVAL;
}
spin_lock_irqsave(&s->lock, flags);
- if (is_write) {
- if (copy_from_user(p, data, 4))
- ret = -EFAULT;
- } else {
- if (copy_to_user(data, p, 4))
- ret = -EFAULT;
- }
+ if (is_write)
+ memcpy(p, data, 4);
+ else
+ memcpy(data, p, 4);
spin_unlock_irqrestore(&s->lock, flags);
return ret;
@@ -584,7 +579,14 @@ static int kvm_eiointc_get_attr(struct kvm_device *dev,
return ret;
case KVM_DEV_LOONGARCH_EXTIOI_GRP_SW_STATUS:
- return kvm_eiointc_sw_status_access(dev, attr, false);
+ ret = kvm_eiointc_sw_status_access(dev, attr, false, &data);
+ if (ret)
+ return ret;
+
+ if (copy_to_user((void __user *)attr->addr, &data, 4))
+ ret = -EFAULT;
+
+ return ret;
default:
return -EINVAL;
}
@@ -604,7 +606,10 @@ static int kvm_eiointc_set_attr(struct kvm_device *dev,
return kvm_eiointc_regs_access(dev, attr, true, &data);
case KVM_DEV_LOONGARCH_EXTIOI_GRP_SW_STATUS:
- return kvm_eiointc_sw_status_access(dev, attr, true);
+ if (copy_from_user(&data, (void __user *)attr->addr, 4))
+ return -EFAULT;
+
+ return kvm_eiointc_sw_status_access(dev, attr, true, &data);
default:
return -EINVAL;
}
--
2.39.3
next prev parent reply other threads:[~2025-09-02 9:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-02 9:49 [PATCH 0/4] Move copy_from_user out of preempt disabled context Bibo Mao
2025-09-02 9:49 ` [PATCH 1/4] LoongArch: KVM: Avoid use copy_from_user with lock hold in kvm_eiointc_regs_access Bibo Mao
2025-09-02 11:58 ` Huacai Chen
2025-09-02 12:15 ` Bibo Mao
2025-09-03 8:34 ` Huacai Chen
2025-09-02 9:49 ` Bibo Mao [this message]
2025-09-02 9:49 ` [PATCH 3/4] LoongArch: KVM: Avoid use copy_from_user with lock hold in kvm_eiointc_ctrl_access Bibo Mao
2025-09-02 9:49 ` [PATCH 4/4] LoongArch: KVM: Avoid use copy_from_user with lock hold in kvm_pch_pic_regs_access Bibo Mao
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