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Message-ID: <334bd4dde8e0a88eb30fa67eeef61827cdb546f9.1730836219.git.nicolinc@nvidia.com>
Date: Tue, 5 Nov 2024 12:04:20 -0800
From: Nicolin Chen <nicolinc@...dia.com>
To: <jgg@...dia.com>, <kevin.tian@...el.com>, <corbet@....net>
CC: <joro@...tes.org>, <suravee.suthikulpanit@....com>, <will@...nel.org>,
<robin.murphy@....com>, <dwmw2@...radead.org>, <shuah@...nel.org>,
<iommu@...ts.linux.dev>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linux-kselftest@...r.kernel.org>,
<baolu.lu@...ux.intel.com>, <eric.auger@...hat.com>,
<jean-philippe@...aro.org>, <mdf@...nel.org>, <mshavit@...gle.com>,
<shameerali.kolothum.thodi@...wei.com>, <smostafa@...gle.com>,
<yi.l.liu@...el.com>, <aik@....com>, <zhangfei.gao@...aro.org>,
<patches@...ts.linux.dev>
Subject: [PATCH v7 04/13] iommufd: Verify object in iommufd_object_finalize/abort()
To support driver-allocated vIOMMU objects, it's required for IOMMU driver
to call the provided iommufd_viommu_alloc helper to embed the core struct.
However, there is no guarantee that every driver will call it and allocate
objects properly.
Make the iommufd_object_finalize/abort functions more robust to verify if
the xarray slot indexed by the input obj->id is having an XA_ZERO_ENTRY,
which is the reserved value stored by xa_alloc via iommufd_object_alloc.
Suggested-by: Jason Gunthorpe <jgg@...dia.com>
Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
---
drivers/iommu/iommufd/main.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 3c32b440471b..30e6c2af3b45 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -41,20 +41,26 @@ static struct miscdevice vfio_misc_dev;
void iommufd_object_finalize(struct iommufd_ctx *ictx,
struct iommufd_object *obj)
{
+ XA_STATE(xas, &ictx->objects, obj->id);
void *old;
- old = xa_store(&ictx->objects, obj->id, obj, GFP_KERNEL);
- /* obj->id was returned from xa_alloc() so the xa_store() cannot fail */
- WARN_ON(old);
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, obj);
+ xa_unlock(&ictx->objects);
+ /* obj->id was returned from xa_alloc() so the xas_store() cannot fail */
+ WARN_ON(old != XA_ZERO_ENTRY);
}
/* Undo _iommufd_object_alloc() if iommufd_object_finalize() was not called */
void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj)
{
+ XA_STATE(xas, &ictx->objects, obj->id);
void *old;
- old = xa_erase(&ictx->objects, obj->id);
- WARN_ON(old);
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, NULL);
+ xa_unlock(&ictx->objects);
+ WARN_ON(old != XA_ZERO_ENTRY);
kfree(obj);
}
--
2.43.0
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