From e323369b2e204da4dc771bbddceef986f4bf85d5 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Wed, 28 Jun 2017 13:49:52 -0600 Subject: kvm-vfio: Decouple only when we match a group Unset-KVM and decrement-assignment only when we find the group in our list. Otherwise we can get out of sync if the user triggers this for groups that aren't currently on our list. Signed-off-by: Alex Williamson Reviewed-by: Alexey Kardashevskiy Reviewed-by: Eric Auger Tested-by: Eric Auger Acked-by: Paolo Bonzini Cc: stable@vger.kernel.org --- virt/kvm/vfio.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'virt/kvm') diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c index 37d9118fd84b..6e002d0f3191 100644 --- a/virt/kvm/vfio.c +++ b/virt/kvm/vfio.c @@ -246,21 +246,20 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) continue; list_del(&kvg->node); + kvm_arch_end_assignment(dev->kvm); +#ifdef CONFIG_SPAPR_TCE_IOMMU + kvm_spapr_tce_release_vfio_group(dev->kvm, + kvg->vfio_group); +#endif + kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); kvm_vfio_group_put_external_user(kvg->vfio_group); kfree(kvg); ret = 0; break; } - kvm_arch_end_assignment(dev->kvm); - mutex_unlock(&kv->lock); -#ifdef CONFIG_SPAPR_TCE_IOMMU - kvm_spapr_tce_release_vfio_group(dev->kvm, vfio_group); -#endif - kvm_vfio_group_set_kvm(vfio_group, NULL); - kvm_vfio_group_put_external_user(vfio_group); kvm_vfio_update_coherency(dev); -- cgit v1.2.3 From 5d6dee80a1e94cc284d03e06d930e60e8d3ecf7d Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Wed, 28 Jun 2017 13:50:05 -0600 Subject: vfio: New external user group/file match At the point where the kvm-vfio pseudo device wants to release its vfio group reference, we can't always acquire a new reference to make that happen. The group can be in a state where we wouldn't allow a new reference to be added. This new helper function allows a caller to match a file to a group to facilitate this. Given a file and group, report if they match. Thus the caller needs to already have a group reference to match to the file. This allows the deletion of a group without acquiring a new reference. Signed-off-by: Alex Williamson Reviewed-by: Eric Auger Reviewed-by: Paolo Bonzini Tested-by: Eric Auger Cc: stable@vger.kernel.org --- drivers/vfio/vfio.c | 9 +++++++++ include/linux/vfio.h | 2 ++ virt/kvm/vfio.c | 27 +++++++++++++++++++-------- 3 files changed, 30 insertions(+), 8 deletions(-) (limited to 'virt/kvm') diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 54dd2fbf83d9..7597a377eb4e 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1776,6 +1776,15 @@ void vfio_group_put_external_user(struct vfio_group *group) } EXPORT_SYMBOL_GPL(vfio_group_put_external_user); +bool vfio_external_group_match_file(struct vfio_group *test_group, + struct file *filep) +{ + struct vfio_group *group = filep->private_data; + + return (filep->f_op == &vfio_group_fops) && (group == test_group); +} +EXPORT_SYMBOL_GPL(vfio_external_group_match_file); + int vfio_external_user_iommu_id(struct vfio_group *group) { return iommu_group_id(group->iommu_group); diff --git a/include/linux/vfio.h b/include/linux/vfio.h index edf9b2cad277..9b34d0af5d27 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -97,6 +97,8 @@ extern void vfio_unregister_iommu_driver( */ extern struct vfio_group *vfio_group_get_external_user(struct file *filep); extern void vfio_group_put_external_user(struct vfio_group *group); +extern bool vfio_external_group_match_file(struct vfio_group *group, + struct file *filep); extern int vfio_external_user_iommu_id(struct vfio_group *group); extern long vfio_external_check_extension(struct vfio_group *group, unsigned long arg); diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c index 6e002d0f3191..d99850c462a1 100644 --- a/virt/kvm/vfio.c +++ b/virt/kvm/vfio.c @@ -51,6 +51,22 @@ static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep) return vfio_group; } +static bool kvm_vfio_external_group_match_file(struct vfio_group *group, + struct file *filep) +{ + bool ret, (*fn)(struct vfio_group *, struct file *); + + fn = symbol_get(vfio_external_group_match_file); + if (!fn) + return false; + + ret = fn(group, filep); + + symbol_put(vfio_external_group_match_file); + + return ret; +} + static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group) { void (*fn)(struct vfio_group *); @@ -231,18 +247,13 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) if (!f.file) return -EBADF; - vfio_group = kvm_vfio_group_get_external_user(f.file); - fdput(f); - - if (IS_ERR(vfio_group)) - return PTR_ERR(vfio_group); - ret = -ENOENT; mutex_lock(&kv->lock); list_for_each_entry(kvg, &kv->group_list, node) { - if (kvg->vfio_group != vfio_group) + if (!kvm_vfio_external_group_match_file(kvg->vfio_group, + f.file)) continue; list_del(&kvg->node); @@ -260,7 +271,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) mutex_unlock(&kv->lock); - kvm_vfio_group_put_external_user(vfio_group); + fdput(f); kvm_vfio_update_coherency(dev); -- cgit v1.2.3