iommu/amd: Introduce amd_iommu_update_ga()

Introduces a new IOMMU API, amd_iommu_update_ga(), which allows
KVM (SVM) to update existing posted interrupt IOMMU IRTE when
load/unload vcpu.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd_iommu.c

@@ -4269,4 +4269,43 @@ int amd_iommu_create_irq_domain(struct amd_iommu *iommu)
 
 	return 0;
 }
+
+int amd_iommu_update_ga(int cpu, bool is_run, void *data)
+{
+	unsigned long flags;
+	struct amd_iommu *iommu;
+	struct irq_remap_table *irt;
+	struct amd_ir_data *ir_data = (struct amd_ir_data *)data;
+	int devid = ir_data->irq_2_irte.devid;
+	struct irte_ga *entry = (struct irte_ga *) ir_data->entry;
+	struct irte_ga *ref = (struct irte_ga *) ir_data->ref;
+
+	if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) ||
+	    !ref || !entry || !entry->lo.fields_vapic.guest_mode)
+		return 0;
+
+	iommu = amd_iommu_rlookup_table[devid];
+	if (!iommu)
+		return -ENODEV;
+
+	irt = get_irq_table(devid, false);
+	if (!irt)
+		return -ENODEV;
+
+	spin_lock_irqsave(&irt->lock, flags);
+
+	if (ref->lo.fields_vapic.guest_mode) {
+		if (cpu >= 0)
+			ref->lo.fields_vapic.destination = cpu;
+		ref->lo.fields_vapic.is_run = is_run;
+		barrier();
+	}
+
+	spin_unlock_irqrestore(&irt->lock, flags);
+
+	iommu_flush_irt(iommu, devid);
+	iommu_completion_wait(iommu);
+	return 0;
+}
+EXPORT_SYMBOL(amd_iommu_update_ga);
 #endif

drivers/iommu/amd_iommu_types.h

@@ -810,6 +810,7 @@ struct amd_ir_data {
 	struct irq_2_irte irq_2_irte;
 	struct msi_msg msi_entry;
 	void *entry;    /* Pointer to union irte or struct irte_ga */
+	void *ref;      /* Pointer to the actual irte */
 };
 
 struct amd_irte_ops {

include/linux/amd-iommu.h

@@ -179,6 +179,9 @@ static inline int amd_iommu_detect(void) { return -ENODEV; }
 /* IOMMU AVIC Function */
 extern int amd_iommu_register_ga_log_notifier(int (*notifier)(u32));
 
+extern int
+amd_iommu_update_ga(int cpu, bool is_run, void *data);
+
 #else /* defined(CONFIG_AMD_IOMMU) && defined(CONFIG_IRQ_REMAP) */
 
 static inline int
@@ -187,6 +190,12 @@ amd_iommu_register_ga_log_notifier(int (*notifier)(u32))
 	return 0;
 }
 
+static inline int
+amd_iommu_update_ga(int cpu, bool is_run, void *data)
+{
+	return 0;
+}
+
 #endif /* defined(CONFIG_AMD_IOMMU) && defined(CONFIG_IRQ_REMAP) */
 
 #endif /* _ASM_X86_AMD_IOMMU_H */