Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1670892
| From | Alex Williamson <alex.williamson@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 3/9] vfio: New external user group/file match |
| Date | 2017-06-20 17:50 +0200 |
| Message-ID | <tUtzI-238-33@gated-at.bofh.it> (permalink) |
| References | <tUtzH-238-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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 <alex.williamson@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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(-)
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);
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH v3 0/9] vfio: Fix release ordering races and use driver_override Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
[PATCH v3 9/9] vfio: Add AMBA driver_override support Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
Re: [PATCH v3 9/9] vfio: Add AMBA driver_override support Auger Eric <eric.auger@redhat.com> - 2017-06-26 09:40 +0200
[PATCH v3 4/9] iommu: Add driver-not-bound notification Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
[PATCH v3 6/9] vfio: Register pci, platform, amba, and mdev bus drivers Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
[PATCH v3 3/9] vfio: New external user group/file match Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
[PATCH v3 1/9] vfio: Fix group release deadlock Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
[PATCH v3 7/9] vfio: Use driver_override to avert binding to compromising drivers Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
Re: [PATCH v3 7/9] vfio: Use driver_override to avert binding to compromising drivers Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-06-26 11:10 +0200
Re: [PATCH v3 7/9] vfio: Use driver_override to avert binding to compromising drivers Alex Williamson <alex.williamson@redhat.com> - 2017-06-26 21:40 +0200
[PATCH v3 5/9] vfio: Create interface for vfio bus drivers to register Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
[PATCH v3 8/9] amba: Export amba_bustype Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 17:50 +0200
Re: [PATCH v3 8/9] amba: Export amba_bustype Auger Eric <eric.auger@redhat.com> - 2017-06-26 09:40 +0200
[PATCH v3 2/9] kvm-vfio: Decouple only when we match a group Alex Williamson <alex.williamson@redhat.com> - 2017-06-20 18:00 +0200
Re: [PATCH v3 2/9] kvm-vfio: Decouple only when we match a group Auger Eric <eric.auger@redhat.com> - 2017-06-26 09:40 +0200
Re: [PATCH v3 2/9] kvm-vfio: Decouple only when we match a group Paolo Bonzini <pbonzini@redhat.com> - 2017-06-28 20:00 +0200
Re: [PATCH v3 0/9] vfio: Fix release ordering races and use driver_override Auger Eric <eric.auger@redhat.com> - 2017-06-26 09:40 +0200
csiph-web