| Message ID | a104b334d3cc148620ac1f2aa465fc14be556e63.1677288789.git.nicolinc@nvidia.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add IO page table replacement support for emulated pathway | expand |
> From: Nicolin Chen <nicolinc@nvidia.com> > Sent: Saturday, February 25, 2023 9:52 AM > > + /* > + * 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; > + > + mutex_unlock(&access->ioas_lock); > + access->ops->unmap(access->data, 0, ULONG_MAX); > + mutex_lock(&access->ioas_lock); This should check whether @unmap is valid.
On Thu, Mar 02, 2023 at 08:23:54AM +0000, Tian, Kevin wrote: > External email: Use caution opening links or attachments > > > > From: Nicolin Chen <nicolinc@nvidia.com> > > Sent: Saturday, February 25, 2023 9:52 AM > > > > + /* > > + * 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; > > + > > + mutex_unlock(&access->ioas_lock); > > + access->ops->unmap(access->data, 0, ULONG_MAX); > > + mutex_lock(&access->ioas_lock); > > This should check whether @unmap is valid. Will change to + if (access->ops->unmap) { + mutex_unlock(&access->ioas_lock); + access->ops->unmap(access->data, 0, ULONG_MAX); + mutex_lock(&access->ioas_lock); + } Thanks! Nic
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index a955ebd4bd5d..c44d6e7a2ed7 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -712,11 +712,22 @@ int iommufd_access_set_ioas(struct iommufd_access *access, u32 ioas_id) iommufd_ref_to_users(obj); } + /* + * 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; + + mutex_unlock(&access->ioas_lock); + access->ops->unmap(access->data, 0, ULONG_MAX); + mutex_lock(&access->ioas_lock); + if (cur_ioas) { iopt_remove_access(&cur_ioas->iopt, access); refcount_dec(&cur_ioas->obj.users); } + access->ioas_unpin = new_ioas; access->ioas = new_ioas; mutex_unlock(&access->ioas_lock); @@ -790,11 +801,11 @@ void iommufd_access_unpin_pages(struct iommufd_access *access, return; mutex_lock(&access->ioas_lock); - if (!access->ioas) { + if (!access->ioas_unpin) { mutex_unlock(&access->ioas_lock); return; } - iopt = &access->ioas->iopt; + iopt = &access->ioas_unpin->iopt; down_read(&iopt->iova_rwsem); iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 94e88377a7fc..44e77ea9c399 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -311,6 +311,7 @@ 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;
Support an access->ioas replacement in iommufd_access_set_ioas(), which sets the access->ioas to NULL provisionally so that any further incoming iommufd_access_pin_pages() callback can be blocked. Then, call access->ops->unmap() to clean up the entire iopt. To allow an 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 above. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> --- drivers/iommu/iommufd/device.c | 15 +++++++++++++-- drivers/iommu/iommufd/iommufd_private.h | 1 + 2 files changed, 14 insertions(+), 2 deletions(-)