[Xen-devel] [PATCH 5/5] VT-d: adjust IOMMU interrupt affinities when all CPUs are online

["Jan Beulich" <JBeulich@xxxxxxxx>]

Since these interrupts get setup before APs get brought online, their
affinities naturally could only ever point to CPU 0 alone so far.
Adjust this to include potentially multiple CPUs in the target mask
(when running in one of the cluster modes), and take into account NUMA
information (to handle the interrupts on a CPU on the node where the
respective IOMMU is).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -839,6 +839,7 @@ void acpi_dmar_reinstate(void)
 
 void acpi_dmar_zap(void)
 {
+    adjust_vtd_irq_affinities();
     if ( dmar_table == NULL )
         return;
     dmar_table->signature[0] = 'X';
--- a/xen/drivers/passthrough/vtd/extern.h
+++ b/xen/drivers/passthrough/vtd/extern.h
@@ -52,6 +52,7 @@ int invalidate_sync(struct iommu *iommu)
 int iommu_flush_iec_global(struct iommu *iommu);
 int iommu_flush_iec_index(struct iommu *iommu, u8 im, u16 iidx);
 void clear_fault_bits(struct iommu *iommu);
+int adjust_vtd_irq_affinities(void);
 
 struct iommu * ioapic_to_iommu(unsigned int apic_id);
 struct iommu * hpet_to_iommu(unsigned int hpet_id);
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1971,6 +1971,33 @@ void clear_fault_bits(struct iommu *iomm
     spin_unlock_irqrestore(&iommu->register_lock, flags);
 }
 
+static void adjust_irq_affinity(struct acpi_drhd_unit *drhd)
+{
+    const struct acpi_rhsa_unit *rhsa = drhd_to_rhsa(drhd);
+    unsigned int node = rhsa ? pxm_to_node(rhsa->proximity_domain)
+                             : NUMA_NO_NODE;
+    const cpumask_t *cpumask = &cpu_online_map;
+
+    if ( node < MAX_NUMNODES && node_online(node) &&
+         cpumask_intersects(&node_to_cpumask(node), cpumask) )
+        cpumask = &node_to_cpumask(node);
+    dma_msi_set_affinity(irq_to_desc(drhd->iommu->msi.irq), cpumask);
+}
+
+int adjust_vtd_irq_affinities(void)
+{
+    struct acpi_drhd_unit *drhd;
+
+    if ( !iommu_enabled )
+        return 0;
+
+    for_each_drhd_unit ( drhd )
+        adjust_irq_affinity(drhd);
+
+    return 0;
+}
+__initcall(adjust_vtd_irq_affinities);
+
 static int init_vtd_hw(void)
 {
     struct acpi_drhd_unit *drhd;
@@ -1984,13 +2011,10 @@ static int init_vtd_hw(void)
      */
     for_each_drhd_unit ( drhd )
     {
-        struct irq_desc *desc;
+        adjust_irq_affinity(drhd);
 
         iommu = drhd->iommu;
 
-        desc = irq_to_desc(iommu->msi.irq);
-        dma_msi_set_affinity(desc, desc->arch.cpu_mask);
-
         clear_fault_bits(iommu);
 
         spin_lock_irqsave(&iommu->register_lock, flags);

Attachment: VT-d-interrupt-affinity.patch
Description: Text document

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