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x86/PCI: VMD: Separate MSI and MSI-X vector sharing
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Child devices in a VMD domain that want to use MSI are slowing down MSI-X
using devices sharing the same vectors.  Move all MSI usage to a single VMD
vector, and MSI-X devices can share the rest.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jon Derrick <jonathan.derrick@intel.com>
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Keith Busch authored and Bjorn Helgaas committed Jun 20, 2016
1 parent e382dff commit 9c20530
Showing 1 changed file with 8 additions and 4 deletions.
12 changes: 8 additions & 4 deletions arch/x86/pci/vmd.c
Original file line number Diff line number Diff line change
@@ -169,11 +169,14 @@ static irq_hw_number_t vmd_get_hwirq(struct msi_domain_info *info,
* XXX: We can be even smarter selecting the best IRQ once we solve the
* affinity problem.
*/
static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd)
static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *desc)
{
int i, best = 0;
int i, best = 1;
unsigned long flags;

if (!desc->msi_attrib.is_msix || vmd->msix_count == 1)
return &vmd->irqs[0];

raw_spin_lock_irqsave(&list_lock, flags);
for (i = 1; i < vmd->msix_count; i++)
if (vmd->irqs[i].count < vmd->irqs[best].count)
@@ -188,14 +191,15 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
unsigned int virq, irq_hw_number_t hwirq,
msi_alloc_info_t *arg)
{
struct vmd_dev *vmd = vmd_from_bus(msi_desc_to_pci_dev(arg->desc)->bus);
struct msi_desc *desc = arg->desc;
struct vmd_dev *vmd = vmd_from_bus(msi_desc_to_pci_dev(desc)->bus);
struct vmd_irq *vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);

if (!vmdirq)
return -ENOMEM;

INIT_LIST_HEAD(&vmdirq->node);
vmdirq->irq = vmd_next_irq(vmd);
vmdirq->irq = vmd_next_irq(vmd, desc);
vmdirq->virq = virq;

irq_domain_set_info(domain, virq, vmdirq->irq->vmd_vector, info->chip,

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