[PATCH RFC 04/15] drivers/base: Add support for a new IMS irq domain

Dave Jiang
2020-04-21T23:34:16Z

From: Megha Dey <megha.dey@linux.intel.com>

Add support for the creation of a new IMS irq domain. It creates a new
irq chip associated with the IMS domain and adds the necessary domain
operations to it.

Also, add a new config option MSI_IMS which must be enabled by any driver
who would want to use the IMS infrastructure.

Signed-off-by: Megha Dey <megha.dey@linux.intel.com>
---
arch/x86/include/asm/hw_irq.h | 7 +++
drivers/base/Kconfig | 9 +++
drivers/base/Makefile | 1
drivers/base/ims-msi.c | 100 ++++++++++++++++++++++++++++++++++++++
drivers/base/platform-msi.c | 6 +-
drivers/vfio/mdev/mdev_core.c | 6 ++
drivers/vfio/mdev/mdev_private.h | 1
include/linux/mdev.h | 3 +
include/linux/msi.h | 2 +
9 files changed, 131 insertions(+), 4 deletions(-)
create mode 100644 drivers/base/ims-msi.c

diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 4154bc5f6a4e..2e355aa6ba50 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -62,6 +62,7 @@ enum irq_alloc_type {
X86_IRQ_ALLOC_TYPE_MSIX,
X86_IRQ_ALLOC_TYPE_DMAR,
X86_IRQ_ALLOC_TYPE_UV,
+ X86_IRQ_ALLOC_TYPE_IMS,
};

struct irq_alloc_info {
@@ -83,6 +84,12 @@ struct irq_alloc_info {
irq_hw_number_t msi_hwirq;
};
#endif
+#ifdef CONFIG_MSI_IMS
+ struct {
+ struct device *dev;
+ irq_hw_number_t ims_hwirq;
+ };
+#endif
#ifdef CONFIG_X86_IO_APIC
struct {
int ioapic_id;
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 5f0bc74d2409..877e0fdee013 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -209,4 +209,13 @@ config GENERIC_ARCH_TOPOLOGY
appropriate scaling, sysfs interface for reading capacity values at
runtime.

+config MSI_IMS
+ bool "Device Specific Interrupt Message Storage (IMS)"
+ depends on X86
+ select GENERIC_MSI_IRQ_DOMAIN
+ select IRQ_REMAP
+ help
+ This allows device drivers to enable device specific
+ interrupt message storage (IMS) besides standard MSI-X interrupts.
+
endmenu
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 157452080f3d..659b9b0c0b8a 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o
obj-$(CONFIG_PINCTRL) += pinctrl.o
obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
+obj-$(CONFIG_MSI_IMS) += ims-msi.o
obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o

obj-y += test/
diff --git a/drivers/base/ims-msi.c b/drivers/base/ims-msi.c
new file mode 100644
index 000000000000..738f6d153155
--- /dev/null
+++ b/drivers/base/ims-msi.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Support for Device Specific IMS interrupts.
+ *
+ * Copyright © 2019 Intel Corporation.
+ *
+ * Author: Megha Dey <megha.dey@intel.com>
+ */
+
+#include <linux/dmar.h>
+#include <linux/irq.h>
+#include <linux/mdev.h>
+#include <linux/pci.h>
+
+/*
+ * Determine if a dev is mdev or not. Return NULL if not mdev device.
+ * Return mdev's parent dev if success.
+ */
+static inline struct device *mdev_to_parent(struct device *dev)
+{
+ struct device *ret = NULL;
+ struct device *(*fn)(struct device *dev);
+ struct bus_type *bus = symbol_get(mdev_bus_type);
+
+ if (bus && dev->bus == bus) {
+ fn = symbol_get(mdev_dev_to_parent_dev);
+ ret = fn(dev);
+ symbol_put(mdev_dev_to_parent_dev);
+ symbol_put(mdev_bus_type);
+ }
+
+ return ret;
+}
+
+static irq_hw_number_t dev_ims_get_hwirq(struct msi_domain_info *info,
+ msi_alloc_info_t *arg)
+{
+ return arg->ims_hwirq;
+}
+
+static int dev_ims_prepare(struct irq_domain *domain, struct device *dev,
+ int nvec, msi_alloc_info_t *arg)
+{
+ if (dev_is_mdev(dev))
+ dev = mdev_to_parent(dev);
+
+ init_irq_alloc_info(arg, NULL);
+ arg->dev = dev;
+ arg->type = X86_IRQ_ALLOC_TYPE_IMS;
+
+ return 0;
+}
+
+static void dev_ims_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+ arg->ims_hwirq = platform_msi_calc_hwirq(desc);
+}
+
+static struct msi_domain_ops dev_ims_domain_ops = {
+ .get_hwirq = dev_ims_get_hwirq,
+ .msi_prepare = dev_ims_prepare,
+ .set_desc = dev_ims_set_desc,
+};
+
+static struct irq_chip dev_ims_ir_controller = {
+ .name = "IR-DEV-IMS",
+ .irq_ack = irq_chip_ack_parent,
+ .irq_retrigger = irq_chip_retrigger_hierarchy,
+ .irq_set_vcpu_affinity = irq_chip_set_vcpu_affinity_parent,
+ .flags = IRQCHIP_SKIP_SET_WAKE,
+ .irq_write_msi_msg = platform_msi_write_msg,
+};
+
+static struct msi_domain_info ims_ir_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS,
+ .ops = &dev_ims_domain_ops,
+ .chip = &dev_ims_ir_controller,
+ .handler = handle_edge_irq,
+ .handler_name = "edge",
+};
+
+struct irq_domain *arch_create_ims_irq_domain(struct irq_domain *parent,
+ const char *name)
+{
+ struct fwnode_handle *fn;
+ struct irq_domain *domain;
+
+ fn = irq_domain_alloc_named_fwnode(name);
+ if (!fn)
+ return NULL;
+
+ domain = msi_create_irq_domain(fn, &ims_ir_domain_info, parent);
+ if (!domain)
+ return NULL;
+
+ irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI);
+ irq_domain_free_fwnode(fn);
+
+ return domain;
+}
diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 2696aa75983b..59160e8cbfb1 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -31,12 +31,11 @@ struct platform_msi_priv_data {
/* The devid allocator */
static DEFINE_IDA(platform_msi_devid_ida);

-#ifdef GENERIC_MSI_DOMAIN_OPS
/*
* Convert an msi_desc to a globaly unique identifier (per-device
* devid + msi_desc position in the msi_list).
*/
-static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
+irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
{
u32 devid;

@@ -45,6 +44,7 @@ static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
}

+#ifdef GENERIC_MSI_DOMAIN_OPS
static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
{
arg->desc = desc;
@@ -76,7 +76,7 @@ static void platform_msi_update_dom_ops(struct msi_domain_info *info)
ops->set_desc = platform_msi_set_desc;
}

-static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
+void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
{
struct msi_desc *desc = irq_data_get_msi_desc(data);
struct platform_msi_priv_data *priv_data;
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b558d4cfd082..cecc6a6bdbef 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -33,6 +33,12 @@ struct device *mdev_parent_dev(struct mdev_device *mdev)
}
EXPORT_SYMBOL(mdev_parent_dev);

+struct device *mdev_dev_to_parent_dev(struct device *dev)
+{
+ return to_mdev_device(dev)->parent->dev;
+}
+EXPORT_SYMBOL(mdev_dev_to_parent_dev);
+
void *mdev_get_drvdata(struct mdev_device *mdev)
{
return mdev->driver_data;
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 7d922950caaf..c21f1305a76b 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -36,7 +36,6 @@ struct mdev_device {
};

#define to_mdev_device(dev) container_of(dev, struct mdev_device, dev)
-#define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)

struct mdev_type {
struct kobject kobj;
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 0ce30ca78db0..fa2344e239ef 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -144,5 +144,8 @@ void mdev_unregister_driver(struct mdev_driver *drv);
struct device *mdev_parent_dev(struct mdev_device *mdev);
struct device *mdev_dev(struct mdev_device *mdev);
struct mdev_device *mdev_from_dev(struct device *dev);
+struct device *mdev_dev_to_parent_dev(struct device *dev);
+
+#define dev_is_mdev(dev) ((dev)->bus == symbol_get(mdev_bus_type))

#endif /* MDEV_H */
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 3890b143b04d..80386468a7bc 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -418,6 +418,8 @@ int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
unsigned int nvec);
void *platform_msi_get_host_data(struct irq_domain *domain);
+irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc);
+void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */

#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN