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Re: [Xen-devel] [PATCH V2 4/6] iommu/arm: Add lightweight iommu_fwspec support
Hi Oleksandr,
On 8/2/19 5:39 PM, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
We need to have some abstract way to add new device to the IOMMU
based on the generic IOMMU DT binding [1] which can be used for
both DT (right now) and ACPI (in future).
For that reason we can borrow the idea used in Linux these days
called "iommu_fwspec". Having this in, it will be possible
to configure IOMMU master interfaces of the device (device IDs)
from a single common place and avoid keeping almost identifical look-up
s/identifical/identical/
implementations in each IOMMU driver.
There is no need to port the whole implementation of "iommu_fwspec"
to Xen, we could, probably, end up with a much simpler solution,
some "stripped down" version which fits our requirments.
s/requirments/requirements/
So, this patch adds the following:
1. A common structure "iommu_fwspec" to hold the the per-device
firmware data
2. New member "iommu_fwspec" of struct device
3. Functions/helpers to deal with "dev->iommu_fwspec"
It should be noted that in comparing with original "iommu_fwspec"
Xen's variant doesn't contain some fields, which are not really
needed at the moment (ops, flag) and "iommu_fwnode" field was replaced
by "iommu_dev" to avoid porting a lot of code (to support "fwnode_handle")
with little benefit.
Next patch in this series will make use of that support.
[1] https://www.kernel.org/doc/Documentation/devicetree/bindings/iommu/iommu.txt
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
---
xen/drivers/passthrough/arm/Makefile | 2 +-
xen/drivers/passthrough/arm/iommu_fwspec.c | 91 ++++++++++++++++++++++++++++++
xen/include/asm-arm/device.h | 1 +
xen/include/asm-arm/iommu.h | 2 +
xen/include/asm-arm/iommu_fwspec.h | 65 +++++++++++++++++++++
5 files changed, 160 insertions(+), 1 deletion(-)
create mode 100644 xen/drivers/passthrough/arm/iommu_fwspec.c
create mode 100644 xen/include/asm-arm/iommu_fwspec.h
diff --git a/xen/drivers/passthrough/arm/Makefile
b/xen/drivers/passthrough/arm/Makefile
index 4abb87a..5fbad45 100644
--- a/xen/drivers/passthrough/arm/Makefile
+++ b/xen/drivers/passthrough/arm/Makefile
@@ -1,2 +1,2 @@
-obj-y += iommu.o iommu_helpers.o
+obj-y += iommu.o iommu_helpers.o iommu_fwspec.o
obj-$(CONFIG_ARM_SMMU) += smmu.o
diff --git a/xen/drivers/passthrough/arm/iommu_fwspec.c
b/xen/drivers/passthrough/arm/iommu_fwspec.c
new file mode 100644
index 0000000..3474192
--- /dev/null
+++ b/xen/drivers/passthrough/arm/iommu_fwspec.c
@@ -0,0 +1,91 @@
+/*
+ * xen/drivers/passthrough/arm/iommu_fwspec.c
+ *
+ * Contains functions to maintain per-device firmware data
+ *
+ * Based on Linux's iommu_fwspec support you can find at:
+ * drivers/iommu/iommu.c
+ *
+ * Copyright (C) 2019 EPAM Systems Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/lib.h>
+#include <xen/iommu.h>
Please order the headers alphabetically.
NIT: Can you a newline between xen and asm headers?
+#include <asm/device.h>
+#include <asm/iommu_fwspec.h>
+
+int iommu_fwspec_init(struct device *dev, struct device *iommu_dev)
+{
+ struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
+ if ( fwspec )
+ return 0;
+
+ fwspec = xzalloc(struct iommu_fwspec);
+ if ( !fwspec )
+ return -ENOMEM;
+
+ fwspec->iommu_dev = iommu_dev;
+ dev_iommu_fwspec_set(dev, fwspec);
+
+ return 0;
+}
+
+void iommu_fwspec_free(struct device *dev)
+{
+ struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
+ if ( fwspec )
xfree is able to deal with NULL pointer, so the check is not necessary.
+ {
+ xfree(fwspec);
+ dev_iommu_fwspec_set(dev, NULL);
+ }
+}
+
+int iommu_fwspec_add_ids(struct device *dev, uint32_t *ids, int num_ids)
While I realize the prototype is coming from Linux, num_ids cannot be
negative (the code below would not work properly). So the parameter
should be unsigned.
+{
+ struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+ size_t size;
+ int i;
Any variable that can't be negative should be unsigned.
+
+ if ( !fwspec )
+ return -EINVAL;
+
+ size = offsetof(struct iommu_fwspec, ids[fwspec->num_ids + num_ids]);
+ if ( size > sizeof(*fwspec) )
+ {
+ fwspec = _xrealloc(fwspec, size, sizeof(void *));
+ if ( !fwspec )
+ return -ENOMEM;
+
+ dev_iommu_fwspec_set(dev, fwspec);
+ }
+
+ for ( i = 0; i < num_ids; i++ )
+ fwspec->ids[fwspec->num_ids + i] = ids[i];
+
+ fwspec->num_ids += num_ids;
+
+ return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/device.h b/xen/include/asm-arm/device.h
index ee1c3bc..ee7cff2 100644
--- a/xen/include/asm-arm/device.h
+++ b/xen/include/asm-arm/device.h
@@ -18,6 +18,7 @@ struct device
struct dt_device_node *of_node; /* Used by drivers imported from Linux */
#endif
struct dev_archdata archdata;
+ struct iommu_fwspec *iommu_fwspec; /* per-device IOMMU instance data */
};
typedef struct device device_t;
diff --git a/xen/include/asm-arm/iommu.h b/xen/include/asm-arm/iommu.h
index 20d865e..1853bd9 100644
--- a/xen/include/asm-arm/iommu.h
+++ b/xen/include/asm-arm/iommu.h
@@ -14,6 +14,8 @@
#ifndef __ARCH_ARM_IOMMU_H__
#define __ARCH_ARM_IOMMU_H__
+#include <asm/iommu_fwspec.h>
iommu.h does not seem to use anything defined in iommu_fwspec.h. So why
do you include it here?
+
struct arch_iommu
{
/* Private information for the IOMMU drivers */
diff --git a/xen/include/asm-arm/iommu_fwspec.h
b/xen/include/asm-arm/iommu_fwspec.h
new file mode 100644
index 0000000..0676285
--- /dev/null
+++ b/xen/include/asm-arm/iommu_fwspec.h
@@ -0,0 +1,65 @@
+/*
+ * xen/include/asm-arm/iommu_fwspec.h
+ *
+ * Contains a common structure to hold the per-device firmware data and
+ * declaration of functions used to maintain that data
+ *
+ * Based on Linux's iommu_fwspec support you can find at:
+ * include/linux/iommu.h
+ *
+ * Copyright (C) 2019 EPAM Systems Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARCH_ARM_IOMMU_FWSPEC_H__
+#define __ARCH_ARM_IOMMU_FWSPEC_H__
+
+/* per-device IOMMU instance data */
+struct iommu_fwspec {
+ /* device which represents this IOMMU H/W */
Did you intend to say "this device's IOMMU"?
+ struct device *iommu_dev;
+ /* IOMMU driver private data for this device */
+ void *iommu_priv;
+ /* number of associated device IDs */
+ unsigned int num_ids;
+ /* IDs which this device may present to the IOMMU */
+ uint32_t ids[1];
+};
+
+int iommu_fwspec_init(struct device *dev, struct device *iommu_dev);
+void iommu_fwspec_free(struct device *dev);
+int iommu_fwspec_add_ids(struct device *dev, uint32_t *ids, int num_ids);
+
+static inline struct iommu_fwspec *dev_iommu_fwspec_get(struct device *dev)
+{
+ return dev->iommu_fwspec;
+}
+
+static inline void dev_iommu_fwspec_set(struct device *dev,
+ struct iommu_fwspec *fwspec)
+{
+ dev->iommu_fwspec = fwspec;
+}
+
+#endif /* __ARCH_ARM_IOMMU_FWSPEC_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
Cheers,
--
Julien Grall
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