[v2,7/8] iommu: Retire bus ops

Message ID 198e82a6b1a28605409c395da4ec1a67b0e1587b.1674753627.git.robin.murphy@arm.com
State New
Headers
Series iommu: The early demise of bus ops |

Commit Message

Robin Murphy Jan. 26, 2023, 6:26 p.m. UTC
  With the rest of the API internals converted, it's time to finally
tackle probe_device and how we bootstrap the per-device ops association
to begin with. This ends up being disappointingly straightforward, since
fwspec users are already doing it in order to find their of_xlate
callback, and it works out that we can easily do the equivalent for
other drivers too. Then shuffle the remaining awareness of iommu_ops
into the couple of core headers that still need it, and breathe a sigh
of relief.

Ding dong the bus ops are gone!

CC: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: Christoph Hellwig <hch@lst.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v2: Clarify the iommu_ops_from_fwnode(NULL) assumption [Baolu]

 drivers/iommu/iommu.c       | 28 +++++++++++++++++-----------
 include/acpi/acpi_bus.h     |  2 ++
 include/linux/device.h      |  1 -
 include/linux/device/bus.h  |  5 -----
 include/linux/dma-map-ops.h |  1 +
 5 files changed, 20 insertions(+), 17 deletions(-)
  

Comments

Baolu Lu Jan. 28, 2023, 12:10 p.m. UTC | #1
On 2023/1/27 2:26, Robin Murphy wrote:
> With the rest of the API internals converted, it's time to finally
> tackle probe_device and how we bootstrap the per-device ops association
> to begin with. This ends up being disappointingly straightforward, since
> fwspec users are already doing it in order to find their of_xlate
> callback, and it works out that we can easily do the equivalent for
> other drivers too. Then shuffle the remaining awareness of iommu_ops
> into the couple of core headers that still need it, and breathe a sigh
> of relief.
> 
> Ding dong the bus ops are gone!
> 
> CC: Rafael J. Wysocki<rafael.j.wysocki@intel.com>
> CC: Christoph Hellwig<hch@lst.de>
> Acked-by: Greg Kroah-Hartman<gregkh@linuxfoundation.org>
> Signed-off-by: Robin Murphy<robin.murphy@arm.com>

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu
  
kernel test robot Jan. 28, 2023, 12:55 p.m. UTC | #2
Hi Robin,

I love your patch! Yet something to improve:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on linus/master v6.2-rc5]
[cannot apply to joro-iommu/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Robin-Murphy/iommu-Decouple-iommu_present-from-bus-ops/20230128-141510
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/198e82a6b1a28605409c395da4ec1a67b0e1587b.1674753627.git.robin.murphy%40arm.com
patch subject: [PATCH v2 7/8] iommu: Retire bus ops
config: s390-randconfig-r012-20230123 (https://download.01.org/0day-ci/archive/20230128/202301282015.hjj2YFYy-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 4196ca3278f78c6e19246e54ab0ecb364e37d66a)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/399f4b37d8065bffafeec12de1344a7ff6098e64
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Robin-Murphy/iommu-Decouple-iommu_present-from-bus-ops/20230128-141510
        git checkout 399f4b37d8065bffafeec12de1344a7ff6098e64
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/iommu/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from drivers/iommu/iommufd/selftest.c:7:
   In file included from include/linux/iommu.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:75:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
                                                             ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
   #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
                                                        ^
   In file included from drivers/iommu/iommufd/selftest.c:7:
   In file included from include/linux/iommu.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:75:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
   #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
                                                        ^
   In file included from drivers/iommu/iommufd/selftest.c:7:
   In file included from include/linux/iommu.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:75:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> drivers/iommu/iommufd/selftest.c:276:39: error: field designator 'iommu_ops' does not refer to any field in type 'struct bus_type'
           static struct bus_type mock_bus = { .iommu_ops = &mock_ops };
                                                ^
   12 warnings and 1 error generated.


vim +276 drivers/iommu/iommufd/selftest.c

f4b20bb34c83dc Jason Gunthorpe 2022-11-29  271  
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  272  /* Create an hw_pagetable with the mock domain so we can test the domain ops */
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  273  static int iommufd_test_mock_domain(struct iommufd_ucmd *ucmd,
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  274  				    struct iommu_test_cmd *cmd)
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  275  {
f4b20bb34c83dc Jason Gunthorpe 2022-11-29 @276  	static struct bus_type mock_bus = { .iommu_ops = &mock_ops };
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  277  	struct iommufd_hw_pagetable *hwpt;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  278  	struct selftest_obj *sobj;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  279  	struct iommufd_ioas *ioas;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  280  	int rc;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  281  
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  282  	ioas = iommufd_get_ioas(ucmd, cmd->id);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  283  	if (IS_ERR(ioas))
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  284  		return PTR_ERR(ioas);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  285  
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  286  	sobj = iommufd_object_alloc(ucmd->ictx, sobj, IOMMUFD_OBJ_SELFTEST);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  287  	if (IS_ERR(sobj)) {
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  288  		rc = PTR_ERR(sobj);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  289  		goto out_ioas;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  290  	}
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  291  	sobj->idev.ictx = ucmd->ictx;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  292  	sobj->type = TYPE_IDEV;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  293  	sobj->idev.mock_dev.bus = &mock_bus;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  294  
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  295  	hwpt = iommufd_device_selftest_attach(ucmd->ictx, ioas,
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  296  					      &sobj->idev.mock_dev);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  297  	if (IS_ERR(hwpt)) {
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  298  		rc = PTR_ERR(hwpt);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  299  		goto out_sobj;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  300  	}
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  301  	sobj->idev.hwpt = hwpt;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  302  
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  303  	/* Userspace must destroy both of these IDs to destroy the object */
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  304  	cmd->mock_domain.out_hwpt_id = hwpt->obj.id;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  305  	cmd->mock_domain.out_device_id = sobj->obj.id;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  306  	iommufd_object_finalize(ucmd->ictx, &sobj->obj);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  307  	iommufd_put_object(&ioas->obj);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  308  	return iommufd_ucmd_respond(ucmd, sizeof(*cmd));
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  309  
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  310  out_sobj:
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  311  	iommufd_object_abort(ucmd->ictx, &sobj->obj);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  312  out_ioas:
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  313  	iommufd_put_object(&ioas->obj);
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  314  	return rc;
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  315  }
f4b20bb34c83dc Jason Gunthorpe 2022-11-29  316
  
Jason Gunthorpe Jan. 30, 2023, 2:20 p.m. UTC | #3
On Sat, Jan 28, 2023 at 08:55:09PM +0800, kernel test robot wrote:

> >> drivers/iommu/iommufd/selftest.c:276:39: error: field designator 'iommu_ops' does not refer to any field in type 'struct bus_type'
>            static struct bus_type mock_bus = { .iommu_ops = &mock_ops };

So this shortcut isn't going to work..

Probably something like this is the simplest thing:

diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index cfb5fe9a5e0ee8..27bab42b1ff841 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -274,6 +274,8 @@ static int iommufd_test_mock_domain(struct iommufd_ucmd *ucmd,
                                    struct iommu_test_cmd *cmd)
 {
        static struct bus_type mock_bus = { .iommu_ops = &mock_ops };
+       static struct iommu_device mock_iommu = { .ops = &mock_ops };
+       static struct dev_iommu mock_dev_iommu = { .iommu_dev = &mock_iommu };
        struct iommufd_hw_pagetable *hwpt;
        struct selftest_obj *sobj;
        struct iommufd_ioas *ioas;
@@ -291,6 +293,7 @@ static int iommufd_test_mock_domain(struct iommufd_ucmd *ucmd,
        sobj->idev.ictx = ucmd->ictx;
        sobj->type = TYPE_IDEV;
        sobj->idev.mock_dev.bus = &mock_bus;
+       sobj->idev.mock_dev.iommu = &mock_dev_iommu;
 
        hwpt = iommufd_device_selftest_attach(ucmd->ictx, ioas,
                                              &sobj->idev.mock_dev);

And then delete mock_bus at this patch

Jason
  
Jason Gunthorpe Jan. 30, 2023, 5:09 p.m. UTC | #4
On Thu, Jan 26, 2023 at 06:26:22PM +0000, Robin Murphy wrote:
> With the rest of the API internals converted, it's time to finally
> tackle probe_device and how we bootstrap the per-device ops association
> to begin with. This ends up being disappointingly straightforward, since
> fwspec users are already doing it in order to find their of_xlate
> callback, and it works out that we can easily do the equivalent for
> other drivers too. Then shuffle the remaining awareness of iommu_ops
> into the couple of core headers that still need it, and breathe a sigh
> of relief.
> 
> Ding dong the bus ops are gone!
> 
> CC: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> CC: Christoph Hellwig <hch@lst.de>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason
  

Patch

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index bdc5fdf39d2b..7fb7c84e3dc6 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -219,13 +219,6 @@  int iommu_device_register(struct iommu_device *iommu,
 	/* We need to be able to take module references appropriately */
 	if (WARN_ON(is_module_address((unsigned long)ops) && !ops->owner))
 		return -EINVAL;
-	/*
-	 * Temporarily enforce global restriction to a single driver. This was
-	 * already the de-facto behaviour, since any possible combination of
-	 * existing drivers would compete for at least the PCI or platform bus.
-	 */
-	if (iommu_buses[0]->iommu_ops && iommu_buses[0]->iommu_ops != ops)
-		return -EBUSY;
 
 	iommu->ops = ops;
 	if (hwdev)
@@ -235,10 +228,8 @@  int iommu_device_register(struct iommu_device *iommu,
 	list_add_tail(&iommu->list, &iommu_device_list);
 	spin_unlock(&iommu_device_lock);
 
-	for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) {
-		iommu_buses[i]->iommu_ops = ops;
+	for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++)
 		err = bus_iommu_probe(iommu_buses[i]);
-	}
 	if (err)
 		iommu_device_unregister(iommu);
 	return err;
@@ -310,12 +301,27 @@  static u32 dev_iommu_get_max_pasids(struct device *dev)
 
 static int __iommu_probe_device(struct device *dev, struct list_head *group_list)
 {
-	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	const struct iommu_ops *ops;
 	struct iommu_device *iommu_dev;
+	struct iommu_fwspec *fwspec;
 	struct iommu_group *group;
 	static DEFINE_MUTEX(iommu_probe_device_lock);
 	int ret;
 
+	/*
+	 * For FDT-based systems and ACPI IORT/VIOT, drivers register IOMMU
+	 * instances with non-NULL fwnodes, and client devices should have been
+	 * identified with a fwspec by this point. Otherwise, we can currently
+	 * assume that only one of Intel, AMD, s390, PAMU or legacy SMMUv2 can
+	 * be present, and that any of their registered instances has suitable
+	 * ops for probing, and thus cheekily co-opt the same mechanism.
+	 */
+	fwspec = dev_iommu_fwspec_get(dev);
+	if (fwspec && fwspec->ops)
+		ops = fwspec->ops;
+	else
+		ops = iommu_ops_from_fwnode(NULL);
+
 	if (!ops)
 		return -ENODEV;
 	/*
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index cd3b75e08ec3..067dde9291c9 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -614,6 +614,8 @@  struct acpi_pci_root {
 
 /* helper */
 
+struct iommu_ops;
+
 bool acpi_dma_supported(const struct acpi_device *adev);
 enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev);
 int acpi_iommu_fwspec_init(struct device *dev, u32 id,
diff --git a/include/linux/device.h b/include/linux/device.h
index 44e3acae7b36..f7a7ecafedd3 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -41,7 +41,6 @@  struct class;
 struct subsys_private;
 struct device_node;
 struct fwnode_handle;
-struct iommu_ops;
 struct iommu_group;
 struct dev_pin_info;
 struct dev_iommu;
diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h
index d8b29ccd07e5..4ece3470112f 100644
--- a/include/linux/device/bus.h
+++ b/include/linux/device/bus.h
@@ -63,9 +63,6 @@  struct fwnode_handle;
  *			this bus.
  * @pm:		Power management operations of this bus, callback the specific
  *		device driver's pm-ops.
- * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
- *              driver implementations to a bus and allow the driver to do
- *              bus-specific setup
  * @p:		The private data of the driver core, only the driver core can
  *		touch this.
  * @lock_key:	Lock class key for use by the lock validator
@@ -109,8 +106,6 @@  struct bus_type {
 
 	const struct dev_pm_ops *pm;
 
-	const struct iommu_ops *iommu_ops;
-
 	struct subsys_private *p;
 	struct lock_class_key lock_key;
 
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index d678afeb8a13..e8ebf0bf611b 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -10,6 +10,7 @@ 
 #include <linux/pgtable.h>
 
 struct cma;
+struct iommu_ops;
 
 /*
  * Values for struct dma_map_ops.flags: