From: Yi Liu <yi.l.liu@intel.com>
To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com
Cc: joro@8bytes.org, robin.murphy@arm.com, cohuck@redhat.com,
eric.auger@redhat.com, nicolinc@nvidia.com, kvm@vger.kernel.org,
mjrosato@linux.ibm.com, chao.p.peng@linux.intel.com,
yi.l.liu@intel.com, yi.y.sun@linux.intel.com, peterx@redhat.com,
jasowang@redhat.com, shameerali.kolothum.thodi@huawei.com,
lulu@redhat.com, suravee.suthikulpanit@amd.com,
intel-gvt-dev@lists.freedesktop.org,
intel-gfx@lists.freedesktop.org, linux-s390@vger.kernel.org,
xudong.hao@intel.com, yan.y.zhao@intel.com,
terrence.xu@intel.com, yanting.jiang@intel.com
Subject: [PATCH v8 16/24] iommufd/device: Add iommufd_access_detach() API
Date: Mon, 27 Mar 2023 02:40:39 -0700 [thread overview]
Message-ID: <20230327094047.47215-17-yi.l.liu@intel.com> (raw)
In-Reply-To: <20230327094047.47215-1-yi.l.liu@intel.com>
From: Nicolin Chen <nicolinc@nvidia.com>
Previously, the detach routine is only done by the destroy(). And it was
called by vfio_iommufd_emulated_unbind() when the device runs close(), so
all the mappings in iopt were cleaned in that setup, when the call trace
reaches this detach() routine.
Now, there's a need of a detach uAPI, meaning that it does not only need
a new iommufd_access_detach() API, but also requires access->ops->unmap()
call as a cleanup. So add one.
However, leaving that unprotected can introduce some potential of a race
condition during the pin_/unpin_pages() call, where access->ioas->iopt is
getting referenced. So, add an ioas_lock to protect the context of iopt
referencings.
Also, to allow the iommufd_access_unpin_pages() callback to happen via
this unmap() call, add an ioas_unpin pointer, so the unpin routine won't
be affected by the "access->ioas = NULL" trick.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/iommufd/device.c | 75 +++++++++++++++++++++++--
drivers/iommu/iommufd/iommufd_private.h | 2 +
include/linux/iommufd.h | 1 +
3 files changed, 73 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 04a57aa1ae2c..f0522d80919d 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -493,26 +493,66 @@ void iommufd_access_destroy(struct iommufd_access *access)
}
EXPORT_SYMBOL_NS_GPL(iommufd_access_destroy, IOMMUFD);
+static void __iommufd_access_detach(struct iommufd_access *access)
+{
+ struct iommufd_ioas *cur_ioas = access->ioas;
+
+ lockdep_assert_held(&access->ioas_lock);
+ /*
+ * Set ioas to NULL to block any further iommufd_access_pin_pages().
+ * iommufd_access_unpin_pages() can continue using access->ioas_unpin.
+ */
+ access->ioas = NULL;
+
+ if (access->ops->unmap) {
+ mutex_unlock(&access->ioas_lock);
+ access->ops->unmap(access->data, 0, ULONG_MAX);
+ mutex_lock(&access->ioas_lock);
+ }
+ iopt_remove_access(&cur_ioas->iopt, access);
+ refcount_dec(&cur_ioas->obj.users);
+}
+
+void iommufd_access_detach(struct iommufd_access *access)
+{
+ mutex_lock(&access->ioas_lock);
+ if (WARN_ON(!access->ioas))
+ goto out;
+ __iommufd_access_detach(access);
+out:
+ access->ioas_unpin = NULL;
+ mutex_unlock(&access->ioas_lock);
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_access_detach, IOMMUFD);
+
int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id)
{
struct iommufd_ioas *new_ioas;
int rc = 0;
- if (access->ioas != NULL && access->ioas->obj.id != ioas_id)
+ mutex_lock(&access->ioas_lock);
+ if (access->ioas != NULL && access->ioas->obj.id != ioas_id) {
+ mutex_unlock(&access->ioas_lock);
return -EINVAL;
+ }
new_ioas = iommufd_get_ioas(access->ictx, ioas_id);
- if (IS_ERR(new_ioas))
+ if (IS_ERR(new_ioas)) {
+ mutex_unlock(&access->ioas_lock);
return PTR_ERR(new_ioas);
+ }
rc = iopt_add_access(&new_ioas->iopt, access);
if (rc) {
+ mutex_unlock(&access->ioas_lock);
iommufd_put_object(&new_ioas->obj);
return rc;
}
iommufd_ref_to_users(&new_ioas->obj);
access->ioas = new_ioas;
+ access->ioas_unpin = new_ioas;
+ mutex_unlock(&access->ioas_lock);
return 0;
}
EXPORT_SYMBOL_NS_GPL(iommufd_access_attach, IOMMUFD);
@@ -567,8 +607,8 @@ void iommufd_access_notify_unmap(struct io_pagetable *iopt, unsigned long iova,
void iommufd_access_unpin_pages(struct iommufd_access *access,
unsigned long iova, unsigned long length)
{
- struct io_pagetable *iopt = &access->ioas->iopt;
struct iopt_area_contig_iter iter;
+ struct io_pagetable *iopt;
unsigned long last_iova;
struct iopt_area *area;
@@ -576,6 +616,13 @@ void iommufd_access_unpin_pages(struct iommufd_access *access,
WARN_ON(check_add_overflow(iova, length - 1, &last_iova)))
return;
+ mutex_lock(&access->ioas_lock);
+ if (!access->ioas_unpin) {
+ mutex_unlock(&access->ioas_lock);
+ return;
+ }
+ iopt = &access->ioas_unpin->iopt;
+
down_read(&iopt->iova_rwsem);
iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova)
iopt_area_remove_access(
@@ -585,6 +632,7 @@ void iommufd_access_unpin_pages(struct iommufd_access *access,
min(last_iova, iopt_area_last_iova(area))));
up_read(&iopt->iova_rwsem);
WARN_ON(!iopt_area_contig_done(&iter));
+ mutex_unlock(&access->ioas_lock);
}
EXPORT_SYMBOL_NS_GPL(iommufd_access_unpin_pages, IOMMUFD);
@@ -630,8 +678,8 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
unsigned long length, struct page **out_pages,
unsigned int flags)
{
- struct io_pagetable *iopt = &access->ioas->iopt;
struct iopt_area_contig_iter iter;
+ struct io_pagetable *iopt;
unsigned long last_iova;
struct iopt_area *area;
int rc;
@@ -646,6 +694,13 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
if (check_add_overflow(iova, length - 1, &last_iova))
return -EOVERFLOW;
+ mutex_lock(&access->ioas_lock);
+ if (!access->ioas) {
+ mutex_unlock(&access->ioas_lock);
+ return -ENOENT;
+ }
+ iopt = &access->ioas->iopt;
+
down_read(&iopt->iova_rwsem);
iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) {
unsigned long last = min(last_iova, iopt_area_last_iova(area));
@@ -676,6 +731,7 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
}
up_read(&iopt->iova_rwsem);
+ mutex_unlock(&access->ioas_lock);
return 0;
err_remove:
@@ -690,6 +746,7 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
iopt_area_last_iova(area))));
}
up_read(&iopt->iova_rwsem);
+ mutex_unlock(&access->ioas_lock);
return rc;
}
EXPORT_SYMBOL_NS_GPL(iommufd_access_pin_pages, IOMMUFD);
@@ -709,8 +766,8 @@ EXPORT_SYMBOL_NS_GPL(iommufd_access_pin_pages, IOMMUFD);
int iommufd_access_rw(struct iommufd_access *access, unsigned long iova,
void *data, size_t length, unsigned int flags)
{
- struct io_pagetable *iopt = &access->ioas->iopt;
struct iopt_area_contig_iter iter;
+ struct io_pagetable *iopt;
struct iopt_area *area;
unsigned long last_iova;
int rc;
@@ -720,6 +777,13 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova,
if (check_add_overflow(iova, length - 1, &last_iova))
return -EOVERFLOW;
+ mutex_lock(&access->ioas_lock);
+ if (!access->ioas) {
+ mutex_unlock(&access->ioas_lock);
+ return -ENOENT;
+ }
+ iopt = &access->ioas->iopt;
+
down_read(&iopt->iova_rwsem);
iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) {
unsigned long last = min(last_iova, iopt_area_last_iova(area));
@@ -746,6 +810,7 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova,
rc = -ENOENT;
err_out:
up_read(&iopt->iova_rwsem);
+ mutex_unlock(&access->ioas_lock);
return rc;
}
EXPORT_SYMBOL_NS_GPL(iommufd_access_rw, IOMMUFD);
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 2e6e8e217cce..ec2ce3ef187d 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -263,6 +263,8 @@ struct iommufd_access {
struct iommufd_object obj;
struct iommufd_ctx *ictx;
struct iommufd_ioas *ioas;
+ struct iommufd_ioas *ioas_unpin;
+ struct mutex ioas_lock;
const struct iommufd_access_ops *ops;
void *data;
unsigned long iova_alignment;
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index ac96df406833..9e0e8894dacc 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -47,6 +47,7 @@ iommufd_access_create(struct iommufd_ctx *ictx,
const struct iommufd_access_ops *ops, void *data, u32 *id);
void iommufd_access_destroy(struct iommufd_access *access);
int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id);
+void iommufd_access_detach(struct iommufd_access *access);
void iommufd_ctx_get(struct iommufd_ctx *ictx);
--
2.34.1
next prev parent reply other threads:[~2023-03-27 9:41 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 9:40 [PATCH v8 00/24] Add vfio_device cdev for iommufd support Yi Liu
2023-03-27 9:40 ` [PATCH v8 01/24] vfio: Allocate per device file structure Yi Liu
2023-03-27 9:40 ` [PATCH v8 02/24] vfio: Refine vfio file kAPIs for KVM Yi Liu
2023-03-27 9:40 ` [PATCH v8 03/24] vfio: Remove vfio_file_is_group() Yi Liu
2023-03-30 23:50 ` Jason Gunthorpe
2023-03-27 9:40 ` [PATCH v8 04/24] vfio: Accept vfio device file in the KVM facing kAPI Yi Liu
2023-03-27 9:40 ` [PATCH v8 05/24] kvm/vfio: Rename kvm_vfio_group to prepare for accepting vfio device fd Yi Liu
2023-03-27 9:40 ` [PATCH v8 06/24] kvm/vfio: Accept vfio device file from userspace Yi Liu
2023-03-27 9:40 ` [PATCH v8 07/24] vfio: Pass struct vfio_device_file * to vfio_device_open/close() Yi Liu
2023-03-27 9:40 ` [PATCH v8 08/24] vfio: Block device access via device fd until device is opened Yi Liu
2023-03-28 21:33 ` Alex Williamson
2023-03-29 2:23 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 09/24] vfio: Add cdev_device_open_cnt to vfio_group Yi Liu
2023-03-27 9:40 ` [PATCH v8 10/24] vfio: Make vfio_device_open() single open for device cdev path Yi Liu
2023-03-30 23:52 ` Jason Gunthorpe
2023-03-27 9:40 ` [PATCH v8 11/24] vfio: Make vfio_device_first_open() to accept NULL iommufd for noiommu Yi Liu
2023-03-30 23:56 ` Jason Gunthorpe
2023-03-27 9:40 ` [PATCH v8 12/24] vfio-iommufd: Move noiommu support out of vfio_iommufd_bind() Yi Liu
2023-03-27 9:40 ` [PATCH v8 13/24] vfio-iommufd: Split bind/attach into two steps Yi Liu
2023-03-27 9:40 ` [PATCH v8 14/24] vfio: Record devid in vfio_device_file Yi Liu
2023-03-27 9:40 ` [PATCH v8 15/24] vfio-iommufd: Add detach_ioas support for physical VFIO devices Yi Liu
2023-03-27 9:40 ` Yi Liu [this message]
2023-03-28 2:23 ` [PATCH v8 16/24] iommufd/device: Add iommufd_access_detach() API Jon Pan-Doh
2023-03-28 15:54 ` Nicolin Chen
2023-03-29 2:24 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 17/24] vfio-iommufd: Add detach_ioas support for emulated VFIO devices Yi Liu
2023-03-27 9:40 ` [PATCH v8 18/24] vfio: Determine noiommu in vfio_device registration Yi Liu
2023-03-28 6:36 ` Tian, Kevin
2023-03-27 9:40 ` [PATCH v8 19/24] vfio: Name noiommu vfio_device with "noiommu-" prefix Yi Liu
2023-03-28 6:37 ` Tian, Kevin
2023-03-27 9:40 ` [PATCH v8 20/24] vfio: Add cdev for vfio_device Yi Liu
2023-03-29 19:57 ` Alex Williamson
2023-03-30 5:35 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 21/24] vfio: Add VFIO_DEVICE_BIND_IOMMUFD Yi Liu
2023-03-29 21:00 ` Alex Williamson
2023-03-29 23:22 ` Jason Gunthorpe
2023-03-30 12:52 ` Liu, Yi L
2023-03-30 12:59 ` Jason Gunthorpe
2023-03-30 7:09 ` Liu, Yi L
2023-03-30 11:52 ` Jason Gunthorpe
2023-03-30 12:53 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 22/24] vfio: Add VFIO_DEVICE_AT[DE]TACH_IOMMUFD_PT Yi Liu
2023-03-29 21:19 ` Alex Williamson
2023-03-30 13:02 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 23/24] vfio: Compile group optionally Yi Liu
2023-03-29 21:51 ` Alex Williamson
2023-03-30 13:06 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 24/24] docs: vfio: Add vfio device cdev description Yi Liu
2023-03-29 22:47 ` Alex Williamson
2023-03-29 22:57 ` Alex Williamson
2023-03-30 13:11 ` Liu, Yi L
2023-03-27 17:48 ` [PATCH v8 00/24] Add vfio_device cdev for iommufd support Nicolin Chen
2023-03-31 3:10 ` Jiang, Yanting
2023-03-31 5:01 ` Jiang, Yanting
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