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Message-Id: <1432026437-16560-2-git-send-email-feng.wu@intel.com>
Date: Tue, 19 May 2015 17:07:14 +0800
From: Feng Wu <feng.wu@...el.com>
To: tglx@...utronix.de, mingo@...hat.com, hpa@...or.com
Cc: linux-kernel@...r.kernel.org, jiang.liu@...ux.intel.com,
Feng Wu <feng.wu@...el.com>
Subject: [v7 1/4] genirq: Introduce irq_set_vcpu_affinity() to target an interrupt to a VCPU
From: Jiang Liu <jiang.liu@...ux.intel.com>
With Posted-Interrupts support in Intel CPU and IOMMU, an external
interrupt from assigned-devices could be directly delivered to a
virtual CPU in a virtual machine. Instead of hacking KVM and Intel
IOMMU drivers, we propose a platform independent interface to target
an interrupt to a specific virtual CPU in a virtual machine, or set
virtual CPU affinity for an interrupt.
By adopting this new interface and the hierarchy irqdomain, we could
easily support posted-interrupts on Intel platforms, and also provide
flexible enough interfaces for other platforms to support similar
features.
Here is the usage scenario for this interface:
Guest update MSI/MSI-X interrupt configuration
-->QEMU and KVM handle this
-->KVM call this interface (passing posted interrupts descriptor
and guest vector)
-->irq core will transfer the control to IOMMU
-->IOMMU will do the real work of updating IRTE (IRTE has new
format for VT-d Posted-Interrupts)
Signed-off-by: Jiang Liu <jiang.liu@...ux.intel.com>
Signed-off-by: Feng Wu <feng.wu@...el.com>
---
include/linux/irq.h | 6 ++++++
kernel/irq/chip.c | 14 ++++++++++++++
kernel/irq/manage.c | 31 +++++++++++++++++++++++++++++++
3 files changed, 51 insertions(+)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 62c6901..48cb7d1 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -327,6 +327,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
* @irq_write_msi_msg: optional to write message content for MSI
* @irq_get_irqchip_state: return the internal state of an interrupt
* @irq_set_irqchip_state: set the internal state of a interrupt
+ * @irq_set_vcpu_affinity: optional to target a vCPU in a virtual machine
* @flags: chip specific flags
*/
struct irq_chip {
@@ -369,6 +370,8 @@ struct irq_chip {
int (*irq_get_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool *state);
int (*irq_set_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool state);
+ int (*irq_set_vcpu_affinity)(struct irq_data *data, void *vcpu_info);
+
unsigned long flags;
};
@@ -422,6 +425,7 @@ extern void irq_cpu_online(void);
extern void irq_cpu_offline(void);
extern int irq_set_affinity_locked(struct irq_data *data,
const struct cpumask *cpumask, bool force);
+extern int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info);
#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ)
void irq_move_irq(struct irq_data *data);
@@ -467,6 +471,8 @@ extern int irq_chip_set_affinity_parent(struct irq_data *data,
const struct cpumask *dest,
bool force);
extern int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on);
+extern int irq_chip_set_vcpu_affinity_parent(struct irq_data *data,
+ void *vcpu_info);
#endif
/* Handling of unhandled and spurious interrupts: */
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index eb9a4ea..55016b2 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -950,6 +950,20 @@ int irq_chip_retrigger_hierarchy(struct irq_data *data)
}
/**
+ * irq_chip_set_vcpu_affinity_parent - Set vcpu affinity on the parent interrupt
+ * @data: Pointer to interrupt specific data
+ * @dest: The vcpu affinity information
+ */
+int irq_chip_set_vcpu_affinity_parent(struct irq_data *data, void *vcpu_info)
+{
+ data = data->parent_data;
+ if (data->chip->irq_set_vcpu_affinity)
+ return data->chip->irq_set_vcpu_affinity(data, vcpu_info);
+
+ return -ENOSYS;
+}
+
+/**
* irq_chip_set_wake_parent - Set/reset wake-up on the parent interrupt
* @data: Pointer to interrupt specific data
* @on: Whether to set or reset the wake-up capability of this irq
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e68932b..b1c7e8f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -256,6 +256,37 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
}
EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
+/**
+ * irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
+ * @irq: interrupt number to set affinity
+ * @vcpu_info: vCPU specific data
+ *
+ * This function uses the vCPU specific data to set the vCPU
+ * affinity for an irq. The vCPU specific data is passed from
+ * outside, such as KVM. One example code path is as below:
+ * KVM -> IOMMU -> irq_set_vcpu_affinity().
+ */
+int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+ struct irq_data *data;
+ struct irq_chip *chip;
+ int ret = -ENOSYS;
+
+ if (!desc)
+ return -EINVAL;
+
+ data = irq_desc_get_irq_data(desc);
+ chip = irq_data_get_irq_chip(data);
+ if (chip && chip->irq_set_vcpu_affinity)
+ ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
+ irq_put_desc_unlock(desc, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
+
static void irq_affinity_notify(struct work_struct *work)
{
struct irq_affinity_notify *notify =
--
2.1.0
--
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