hv: check if the IRQ is intended for a single destination vCPU

Given the vcpumask, check if the IRQ is single destination
and return the destination vCPU if so, the address of associated PI
descriptor for this vCPU can then be passed to dmar_assign_irte() to
set up the posted interrupt IRTE for this device.

For fixed mode interrupt delivery, all vCPUs listed in vcpumask should
service the interrupt requested. But VT-d PI cannot support multicast/broadcast
IRQs, it only supports single CPU destination. So the number of vCPUs
shall be 1 in order to handle IRQ in posted mode for this device.

Add pid_paddr to struct intr_source. If platform_caps.pi is true and
the IRQ is single-destination, pass the physical address of the destination
vCPU's PID to ptirq_build_physical_msi and dmar_assign_irte

Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>

Author: donsheng

hypervisor/arch/x86/guest/assign.c

@@ -12,6 +12,42 @@
 #include <ptdev.h>
 #include <per_cpu.h>
 #include <ioapic.h>
+#include <pgtable.h>
+
+/*
+ * Check if the IRQ is single-destination and return the destination vCPU if so.
+ *
+ * VT-d PI (posted mode) cannot support multicast/broadcast IRQs.
+ * If returns NULL, this means it is multicast/broadcast IRQ and
+ * we can only handle it in remapped mode.
+ * If returns non-NULL, the destination vCPU is returned, which means it is
+ * single-destination IRQ and we can handle it in posted mode.
+ *
+ * @pre (vm != NULL) && (info != NULL)
+ */
+static struct acrn_vcpu *is_single_destination(struct acrn_vm *vm, const struct ptirq_msi_info *info)
+{
+	uint64_t vdmask;
+	uint16_t vid;
+	struct acrn_vcpu *vcpu = NULL;
+
+	vlapic_calc_dest(vm, &vdmask, false, (uint32_t)(info->vmsi_addr.bits.dest_field),
+		(bool)(info->vmsi_addr.bits.dest_mode == MSI_ADDR_DESTMODE_PHYS),
+		(bool)(info->vmsi_data.bits.delivery_mode == MSI_DATA_DELMODE_LOPRI));
+
+	vid = ffs64(vdmask);
+
+	/* Can only post fixed and Lowpri IRQs */
+	if ((info->vmsi_data.bits.delivery_mode == MSI_DATA_DELMODE_FIXED)
+		|| (info->vmsi_data.bits.delivery_mode == MSI_DATA_DELMODE_LOPRI)) {
+		/* Can only post single-destination IRQs */
+		if (vdmask == (1UL << vid)) {
+			vcpu = vcpu_from_vid(vm, vid);
+		}
+	}
+
+	return vcpu;
+}
 
 /*
  * lookup a ptdev entry by sid
@@ -80,8 +116,14 @@ static void ptirq_free_irte(const struct ptirq_remapping_info *entry)
 	dmar_free_irte(&intr_src, (uint16_t)entry->allocated_pirq);
 }
 
+/*
+ * pid_paddr = 0: invalid address, indicate that remapped mode shall be used
+ *
+ * pid_paddr != 0: physical address of posted interrupt descriptor, indicate
+ * that posted mode shall be used
+ */
 static void ptirq_build_physical_msi(struct acrn_vm *vm, struct ptirq_msi_info *info,
-		const struct ptirq_remapping_info *entry, uint32_t vector)
+		const struct ptirq_remapping_info *entry, uint32_t vector, uint64_t pid_paddr)
 {
 	uint64_t vdmask, pdmask;
 	uint32_t dest, delmode, dest_mask;
@@ -116,6 +158,7 @@ static void ptirq_build_physical_msi(struct acrn_vm *vm, struct ptirq_msi_info *
 	irte.bits.remap.dest = dest_mask;
 
 	intr_src.is_msi = true;
+	intr_src.pid_paddr = pid_paddr;
 	intr_src.src.msi.value = entry->phys_sid.msi_id.bdf;
 	ret = dmar_assign_irte(&intr_src, &irte, (uint16_t)entry->allocated_pirq);
 
@@ -212,6 +255,7 @@ ptirq_build_physical_rte(struct acrn_vm *vm, struct ptirq_remapping_info *entry)
 		irte.bits.remap.trigger_mode = rte.bits.trigger_mode;
 
 		intr_src.is_msi = false;
+		intr_src.pid_paddr = 0UL;
 		intr_src.src.ioapic_id = ioapic_irq_to_ioapic_id(phys_irq);
 		ret = dmar_assign_irte(&intr_src, &irte, (uint16_t)phys_irq);
 
@@ -606,13 +650,13 @@ int32_t ptirq_prepare_msix_remap(struct acrn_vm *vm, uint16_t virt_bdf, uint16_t
 				 * All the vCPUs are in x2APIC mode and LAPIC is Pass-through
 				 * Use guest vector to program the interrupt source
 				 */
-				ptirq_build_physical_msi(vm, info, entry, (uint32_t)info->vmsi_data.bits.vector);
+				ptirq_build_physical_msi(vm, info, entry, (uint32_t)info->vmsi_data.bits.vector, 0UL);
 			} else if (vlapic_state == VM_VLAPIC_XAPIC) {
 				/*
 				 * All the vCPUs are in xAPIC mode and LAPIC is emulated
 				 * Use host vector to program the interrupt source
 				 */
-				ptirq_build_physical_msi(vm, info, entry, irq_to_vector(entry->allocated_pirq));
+				ptirq_build_physical_msi(vm, info, entry, irq_to_vector(entry->allocated_pirq), 0UL);
 			} else if (vlapic_state == VM_VLAPIC_TRANSITION) {
 				/*
 				 * vCPUs are in middle of transition, so do not program interrupt source
@@ -626,7 +670,15 @@ int32_t ptirq_prepare_msix_remap(struct acrn_vm *vm, uint16_t virt_bdf, uint16_t
 				ret = -EFAULT;
 			}
 		} else {
-			ptirq_build_physical_msi(vm, info, entry, irq_to_vector(entry->allocated_pirq));
+			struct acrn_vcpu *vcpu = is_single_destination(vm, info);
+
+			if (is_pi_capable(vm) && (vcpu != NULL)) {
+				ptirq_build_physical_msi(vm, info, entry,
+					(uint32_t)info->vmsi_data.bits.vector, hva2hpa(get_pi_desc(vcpu)));
+			} else {
+				/* Go with remapped mode if we cannot handle it in posted mode */
+				ptirq_build_physical_msi(vm, info, entry, irq_to_vector(entry->allocated_pirq), 0UL);
+			}
 		}
 
 		if (ret == 0) {

hypervisor/include/arch/x86/vtd.h

@@ -69,6 +69,13 @@ union source {
 struct intr_source {
 	bool is_msi;
 	union source src;
+	/*
+	 * pid_paddr = 0: invalid address, indicate that remapped mode shall be used
+	 *
+	 * pid_paddr != 0: physical address of posted interrupt descriptor, indicate
+	 * that posted mode shall be used
+	 */
+	uint64_t pid_paddr;
 };
 
 static inline uint8_t dmar_ver_major(uint64_t version)