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authorJiang Liu <jiang.liu@linux.intel.com>2015-05-19 17:07:14 +0800
committerThomas Gleixner <tglx@linutronix.de>2015-05-19 15:41:19 +0200
commit0a4377de305684c883bf90ad21e3cbdeead70f5c (patch)
treeb1212a35515887f4505ba8d6407e02d357b13086 /kernel/irq/manage.c
parent5ebe6afaf0057ac3eaeb98defd5456894b446d22 (diff)
downloadlinux-0a4377de305684c883bf90ad21e3cbdeead70f5c.tar.bz2
genirq: Introduce irq_set_vcpu_affinity() to target an interrupt to a VCPU
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@linux.intel.com> Signed-off-by: Feng Wu <feng.wu@intel.com> Link: http://lkml.kernel.org/r/1432026437-16560-2-git-send-email-feng.wu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq/manage.c')
-rw-r--r--kernel/irq/manage.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e68932bb308e..b1c7e8f46bfb 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 =