x86/IOMMU: abstract Intel-specific adjust_vtd_irq_affinities()

This can't be folded into the resume hook, as that runs before bringing
back up APs, but the affinity adjustment wants to happen with all CPUs
back online. Hence a separate hook is needed such that AMD can then
leverage it as well.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/arch/x86/acpi/power.c

@@ -275,7 +275,7 @@ static int enter_state(u32 state)
     mtrr_aps_sync_begin();
     enable_nonboot_cpus();
     mtrr_aps_sync_end();
-    adjust_vtd_irq_affinities();
+    iommu_adjust_irq_affinities();
     acpi_dmar_zap();
     thaw_domains();
     system_state = SYS_STATE_active;

xen/drivers/passthrough/vtd/iommu.c

@@ -2141,7 +2141,7 @@ static void adjust_irq_affinity(struct acpi_drhd_unit *drhd)
     dma_msi_set_affinity(irq_to_desc(drhd->iommu->msi.irq), cpumask);
 }
 
-int adjust_vtd_irq_affinities(void)
+static int adjust_vtd_irq_affinities(void)
 {
     struct acpi_drhd_unit *drhd;
 
@@ -2725,6 +2725,7 @@ const struct iommu_ops __initconstrel intel_iommu_ops = {
     .read_apic_from_ire = io_apic_read_remap_rte,
     .read_msi_from_ire = msi_msg_read_remap_rte,
     .setup_hpet_msi = intel_setup_hpet_msi,
+    .adjust_irq_affinities = adjust_vtd_irq_affinities,
     .suspend = vtd_suspend,
     .resume = vtd_resume,
     .share_p2m = iommu_set_pgd,

xen/include/asm-x86/iommu.h

@@ -81,8 +81,14 @@ void iommu_update_ire_from_apic(unsigned int apic, unsigned int reg, unsigned in
 unsigned int iommu_read_apic_from_ire(unsigned int apic, unsigned int reg);
 int iommu_setup_hpet_msi(struct msi_desc *);
 
+static inline int iommu_adjust_irq_affinities(void)
+{
+    return iommu_ops.adjust_irq_affinities
+           ? iommu_ops.adjust_irq_affinities()
+           : 0;
+}
+
 /* While VT-d specific, this must get declared in a generic header. */
-int adjust_vtd_irq_affinities(void);
 int __must_check iommu_pte_flush(struct domain *d, u64 gfn, u64 *pte,
                                  int order, int present);
 

xen/include/xen/iommu.h

@@ -224,7 +224,10 @@ struct iommu_ops {
 
     void (*update_ire_from_apic)(unsigned int apic, unsigned int reg, unsigned int value);
     unsigned int (*read_apic_from_ire)(unsigned int apic, unsigned int reg);
+
     int (*setup_hpet_msi)(struct msi_desc *);
+
+    int (*adjust_irq_affinities)(void);
 #endif /* CONFIG_X86 */
 
     int __must_check (*suspend)(void);