This is a note to let you know that I've just added the patch titled
KVM: arm64: vgic: Wrap vgic_its_create() with config_lock
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-arm64-vgic-wrap-vgic_its_create-with-config_lock.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 45ebfb229dfedc3e7ceea40611c5e795168a12f9
Author: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
Date: Thu May 18 11:09:16 2023 +0100
KVM: arm64: vgic: Wrap vgic_its_create() with config_lock
[ Upstream commit 9cf2f840c439b6b23bd99f584f2917ca425ae406 ]
vgic_its_create() changes the vgic state without holding the
config_lock, which triggers a lockdep warning in vgic_v4_init():
[ 358.667941] WARNING: CPU: 3 PID: 178 at arch/arm64/kvm/vgic/vgic-v4.c:245 vgic_v4_init+0x15c/0x7a8
...
[ 358.707410] vgic_v4_init+0x15c/0x7a8
[ 358.708550] vgic_its_create+0x37c/0x4a4
[ 358.709640] kvm_vm_ioctl+0x1518/0x2d80
[ 358.710688] __arm64_sys_ioctl+0x7ac/0x1ba8
[ 358.711960] invoke_syscall.constprop.0+0x70/0x1e0
[ 358.713245] do_el0_svc+0xe4/0x2d4
[ 358.714289] el0_svc+0x44/0x8c
[ 358.715329] el0t_64_sync_handler+0xf4/0x120
[ 358.716615] el0t_64_sync+0x190/0x194
Wrap the whole of vgic_its_create() with config_lock since, in addition
to calling vgic_v4_init(), it also modifies the global kvm->arch.vgic
state.
Fixes: f00327731131 ("KVM: arm64: Use config_lock to protect vgic state")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230518100914.2837292-3-jean-philippe@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 750e51e3779a3..5fe2365a629f2 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -1936,6 +1936,7 @@ void vgic_lpi_translation_cache_destroy(struct kvm *kvm)
static int vgic_its_create(struct kvm_device *dev, u32 type)
{
+ int ret;
struct vgic_its *its;
if (type != KVM_DEV_TYPE_ARM_VGIC_ITS)
@@ -1945,9 +1946,12 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
if (!its)
return -ENOMEM;
+ mutex_lock(&dev->kvm->arch.config_lock);
+
if (vgic_initialized(dev->kvm)) {
- int ret = vgic_v4_init(dev->kvm);
+ ret = vgic_v4_init(dev->kvm);
if (ret < 0) {
+ mutex_unlock(&dev->kvm->arch.config_lock);
kfree(its);
return ret;
}
@@ -1960,12 +1964,10 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
/* Yep, even more trickery for lock ordering... */
#ifdef CONFIG_LOCKDEP
- mutex_lock(&dev->kvm->arch.config_lock);
mutex_lock(&its->cmd_lock);
mutex_lock(&its->its_lock);
mutex_unlock(&its->its_lock);
mutex_unlock(&its->cmd_lock);
- mutex_unlock(&dev->kvm->arch.config_lock);
#endif
its->vgic_its_base = VGIC_ADDR_UNDEF;
@@ -1986,7 +1988,11 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
dev->private = its;
- return vgic_its_set_abi(its, NR_ITS_ABIS - 1);
+ ret = vgic_its_set_abi(its, NR_ITS_ABIS - 1);
+
+ mutex_unlock(&dev->kvm->arch.config_lock);
+
+ return ret;
}
static void vgic_its_destroy(struct kvm_device *kvm_dev)
