From: Yan Zhao <yan.y.zhao@intel.com>
To: Yi Liu <yi.l.liu@intel.com>
Cc: <joro@8bytes.org>, <alex.williamson@redhat.com>, <jgg@nvidia.com>,
<kevin.tian@intel.com>, <robin.murphy@arm.com>,
<baolu.lu@linux.intel.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.y.sun@linux.intel.com>,
<peterx@redhat.com>, <jasowang@redhat.com>,
<shameerali.kolothum.thodi@huawei.com>, <lulu@redhat.com>,
<suravee.suthikulpanit@amd.com>, <iommu@lists.linux.dev>,
<linux-kernel@vger.kernel.org>, <linux-kselftest@vger.kernel.org>,
<zhenzhong.duan@intel.com>, <joao.m.martins@oracle.com>
Subject: Re: [PATCH v4 03/17] iommufd: Unite all kernel-managed members into a struct
Date: Mon, 9 Oct 2023 13:13:45 +0800 [thread overview]
Message-ID: <ZSOMCXBzUMRujp89@yzhao56-desk.sh.intel.com> (raw)
In-Reply-To: <c299567a-5be8-f65f-d8ec-ffd3fa183b03@intel.com>
On Mon, Oct 09, 2023 at 12:13:52PM +0800, Yi Liu wrote:
> On 2023/10/7 18:08, Yan Zhao wrote:
> > On Thu, Sep 21, 2023 at 12:51:24AM -0700, Yi Liu wrote:
> > > From: Nicolin Chen <nicolinc@nvidia.com>
> > >
> > > The struct iommufd_hw_pagetable has been representing a kernel-managed
> > > HWPT, yet soon will be reused to represent a user-managed HWPT. These
> > > two types of HWPTs has the same IOMMUFD object type and an iommu_domain
> > > object, but have quite different attributes/members.
> > >
> > > Add a union in struct iommufd_hw_pagetable and group all the existing
> > > kernel-managed members. One of the following patches will add another
> > > struct for user-managed members.
> > >
> > > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > > Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> > > ---
> > > drivers/iommu/iommufd/iommufd_private.h | 17 +++++++++++------
> > > 1 file changed, 11 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
> > > index 3064997a0181..947a797536e3 100644
> > > --- a/drivers/iommu/iommufd/iommufd_private.h
> > > +++ b/drivers/iommu/iommufd/iommufd_private.h
> > > @@ -231,13 +231,18 @@ int iommufd_vfio_ioas(struct iommufd_ucmd *ucmd);
> > > */
> > > struct iommufd_hw_pagetable {
> > > struct iommufd_object obj;
> > > - struct iommufd_ioas *ioas;
> > > struct iommu_domain *domain;
> > > - bool auto_domain : 1;
> > > - bool enforce_cache_coherency : 1;
> > > - bool msi_cookie : 1;
> > > - /* Head at iommufd_ioas::hwpt_list */
> > > - struct list_head hwpt_item;
> > > +
> > > + union {
> > > + struct { /* kernel-managed */
> > > + struct iommufd_ioas *ioas;
> > > + bool auto_domain : 1;
> > Will iommufd_hw_pagetable_put() also be called on non-kernel-managed domain?
>
> yes.
>
> > If yes, hwpt->user_managed needs to be checked in iommufd_hw_pagetable_put(),
> > (e.g. as below).
> > Otherwise, this union will lead to hwpt->ioas and hwpt->auto_domain still being
> > accessible though invalid.
>
> not quite get this sentence.
I mean with this union, hwpt->auto_domain or hwpt->ioas should only be accessed if and
only if hwpt type is kernel-managed.
So, any unconditional access, as in iommufd_hw_pagetable_put() pasted below, is buggy.
Therefore, do you think it's better to add a filed like "bool kernel_managed : 1",
and access the union fields under /* kernel-managed */ only when hwpt->kernel_managed
is true.
>
> >
> > static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
> > struct iommufd_hw_pagetable *hwpt)
> > {
> > - lockdep_assert_not_held(&hwpt->ioas->mutex);
> > - if (hwpt->auto_domain)
> > + if (!hwpt->user_managed)
> > + lockdep_assert_not_held(&hwpt->ioas->mutex);
>
> this is true. this assert is not needed when hwpt is not kernel managed domain.
>
> > +
> > + if (!hwpt->user_managed && hwpt->auto_domain)
>
> actually, checking auto_domain is more precise. There is hwpt which is
> neither user managed nor auto.
auto_domain is under union fields marked with kernel-managed only.
Access it without type checking is invalid.
struct iommufd_hw_pagetable {
struct iommufd_object obj;
struct iommu_domain *domain;
void (*abort)(struct iommufd_object *obj);
void (*destroy)(struct iommufd_object *obj);
bool user_managed : 1;
union {
struct { /* user-managed */
struct iommufd_hw_pagetable *parent;
};
struct { /* kernel-managed */
struct iommufd_ioas *ioas;
struct mutex mutex;
bool auto_domain : 1;
bool enforce_cache_coherency : 1;
bool msi_cookie : 1;
bool nest_parent : 1;
/* Head at iommufd_ioas::hwpt_list */
struct list_head hwpt_item;
};
};
};
>
> > iommufd_object_deref_user(ictx, &hwpt->obj);
> > else
> > refcount_dec(&hwpt->obj.users);
> > }
> >
> > > + bool enforce_cache_coherency : 1;
> > > + bool msi_cookie : 1;
> > > + /* Head at iommufd_ioas::hwpt_list */
> > > + struct list_head hwpt_item;
> > > + };
> > > + };
> > > };
> > > struct iommufd_hw_pagetable *
> > > --
> > > 2.34.1
> > >
>
> --
> Regards,
> Yi Liu
next prev parent reply other threads:[~2023-10-09 5:42 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-21 7:51 [PATCH v4 00/17] iommufd: Add nesting infrastructure Yi Liu
2023-09-21 7:51 ` [PATCH v4 01/17] iommu: Add hwpt_type with user_data for domain_alloc_user op Yi Liu
2023-09-21 12:10 ` Baolu Lu
2023-09-21 20:58 ` Nicolin Chen
2023-09-25 13:05 ` Jason Gunthorpe
2023-09-25 18:17 ` Nicolin Chen
2023-09-25 6:22 ` Yi Liu
2023-09-25 8:01 ` Baolu Lu
2023-09-25 13:00 ` Jason Gunthorpe
2023-09-21 12:12 ` Baolu Lu
2023-09-21 16:44 ` Jason Gunthorpe
2023-09-22 9:47 ` Robin Murphy
2023-09-25 6:17 ` Yi Liu
2023-09-25 12:59 ` Jason Gunthorpe
2023-09-26 6:37 ` Tian, Kevin
2023-09-26 16:29 ` Jason Gunthorpe
2023-09-27 1:08 ` Tian, Kevin
2023-10-07 9:38 ` Yi Liu
2023-09-26 6:56 ` Tian, Kevin
2023-10-12 9:12 ` Yi Liu
2023-10-13 11:42 ` Yi Liu
2023-10-13 22:22 ` Nicolin Chen
2023-10-10 16:58 ` Jason Gunthorpe
2023-10-12 9:11 ` Yi Liu
2023-10-12 13:39 ` Jason Gunthorpe
2023-10-13 4:33 ` Yi Liu
2023-10-13 14:04 ` Jason Gunthorpe
2023-10-13 17:56 ` Nicolin Chen
2023-10-16 3:28 ` Yi Liu
2023-10-16 11:54 ` Jason Gunthorpe
2023-10-16 18:17 ` Nicolin Chen
2023-10-17 8:51 ` Yi Liu
2023-10-17 9:28 ` Tian, Kevin
2023-10-18 6:12 ` Yi Liu
2023-10-18 16:37 ` Jason Gunthorpe
2023-10-18 16:51 ` Nicolin Chen
2023-10-13 0:34 ` Nicolin Chen
2023-10-13 14:03 ` Jason Gunthorpe
2023-09-21 7:51 ` [PATCH v4 02/17] iommu: Add nested domain support Yi Liu
2023-10-10 17:21 ` Jason Gunthorpe
2023-10-12 9:13 ` Yi Liu
2023-10-14 0:47 ` Nicolin Chen
2023-09-21 7:51 ` [PATCH v4 03/17] iommufd: Unite all kernel-managed members into a struct Yi Liu
2023-09-26 7:46 ` Tian, Kevin
2023-10-07 10:08 ` Yan Zhao
2023-10-09 4:13 ` Yi Liu
2023-10-09 5:13 ` Yan Zhao [this message]
2023-10-10 3:26 ` Yi Liu
2023-09-21 7:51 ` [PATCH v4 04/17] iommufd: Pass in hwpt_type/user_data to iommufd_hw_pagetable_alloc() Yi Liu
2023-09-21 7:51 ` [PATCH v4 05/17] iommufd: Separate kernel-managed HWPT alloc/destroy/abort functions Yi Liu
2023-09-26 7:57 ` Tian, Kevin
2023-10-10 18:49 ` Jason Gunthorpe
2023-10-12 19:09 ` Jason Gunthorpe
2023-10-13 7:13 ` Tian, Kevin
2023-10-13 14:05 ` Jason Gunthorpe
2023-10-16 8:26 ` Tian, Kevin
2023-10-16 12:02 ` Jason Gunthorpe
2023-09-21 7:51 ` [PATCH v4 06/17] iommufd: Add shared alloc_fn function pointer and mutex pointer Yi Liu
2023-09-21 7:51 ` [PATCH v4 07/17] iommufd: Add user-managed hw_pagetable support Yi Liu
2023-09-26 8:14 ` Tian, Kevin
2023-10-14 0:08 ` Nicolin Chen
2023-09-21 7:51 ` [PATCH v4 08/17] iommufd: Always setup MSI and anforce cc on kernel-managed domains Yi Liu
2023-09-26 8:16 ` Tian, Kevin
2023-10-14 0:44 ` Nicolin Chen
2023-10-16 8:48 ` Tian, Kevin
2023-10-16 11:57 ` Jason Gunthorpe
2023-10-17 8:52 ` Tian, Kevin
2023-10-17 15:53 ` Jason Gunthorpe
2023-10-17 19:58 ` Nicolin Chen
2023-10-18 16:51 ` Jason Gunthorpe
2023-10-19 1:56 ` Tian, Kevin
2023-10-19 23:53 ` Jason Gunthorpe
2023-10-20 2:43 ` Tian, Kevin
2023-10-20 13:55 ` Jason Gunthorpe
2023-10-20 18:59 ` Nicolin Chen
2023-10-21 16:38 ` Jason Gunthorpe
2023-10-23 0:18 ` Nicolin Chen
2023-10-23 2:53 ` Tian, Kevin
2023-10-23 18:42 ` Nicolin Chen
2023-10-23 13:59 ` Jason Gunthorpe
2023-10-23 18:49 ` Nicolin Chen
2023-10-18 2:32 ` Baolu Lu
2023-10-17 9:05 ` Tian, Kevin
2023-09-21 7:51 ` [PATCH v4 09/17] iommufd/device: Add helpers to enforce/remove device reserved regions Yi Liu
2023-10-07 7:20 ` Yan Zhao
2023-10-07 9:27 ` Nicolin Chen
2023-09-21 7:51 ` [PATCH v4 10/17] iommufd: Support IOMMU_HWPT_ALLOC allocation with user data Yi Liu
2023-10-13 15:19 ` Jason Gunthorpe
2023-10-13 20:58 ` Nicolin Chen
2023-10-14 0:07 ` Jason Gunthorpe
2023-10-14 0:51 ` Nicolin Chen
2023-10-16 7:03 ` Yi Liu
2023-10-16 11:59 ` Jason Gunthorpe
2023-10-16 18:44 ` Nicolin Chen
2023-10-17 8:55 ` Yi Liu
2023-10-17 15:50 ` Jason Gunthorpe
2023-10-17 19:32 ` Nicolin Chen
2023-09-21 7:51 ` [PATCH v4 11/17] iommufd: Add IOMMU_HWPT_INVALIDATE Yi Liu
2023-09-21 7:51 ` [PATCH v4 12/17] iommufd/selftest: Rework TEST_LENGTH to test min_size explicitly Yi Liu
2023-09-21 7:51 ` [PATCH v4 13/17] iommufd/selftest: Add nested domain allocation for mock domain Yi Liu
2023-09-21 7:51 ` [PATCH v4 14/17] iommufd/selftest: Add coverage for IOMMU_HWPT_ALLOC with nested HWPTs Yi Liu
2023-09-21 7:51 ` [PATCH v4 15/17] iommufd/selftest: Add mock_domain_cache_invalidate_user support Yi Liu
2023-09-21 7:51 ` [PATCH v4 16/17] iommufd/selftest: Add IOMMU_TEST_OP_MD_CHECK_IOTLB test op Yi Liu
2023-09-21 7:51 ` [PATCH v4 17/17] iommufd/selftest: Add coverage for IOMMU_HWPT_INVALIDATE ioctl Yi Liu
2023-10-10 16:53 ` [PATCH v4 00/17] iommufd: Add nesting infrastructure Jason Gunthorpe
2023-10-12 8:45 ` Yi Liu
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