pci: allow to specify IRQ type for PCI devices

Currently all our virtual device interrupts are edge-triggered. But we're
going to need level-triggered interrupts when passing physical devices.
Let the device configure its interrupt kind. Keep edge as default, to
avoid changing existing users.
Reviewed-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm/pci.c

@@ -77,6 +77,7 @@ void pci__generate_fdt_nodes(void *fdt)
 		u8 dev_num = dev_hdr->dev_num;
 		u8 pin = pci_hdr->irq_pin;
 		u8 irq = pci_hdr->irq_line;
+		u32 irq_flags = pci_hdr->irq_type;
 
 		*entry = (struct of_interrupt_map_entry) {
 			.pci_irq_mask = {
@@ -93,7 +94,7 @@ void pci__generate_fdt_nodes(void *fdt)
 			.gic_irq = {
 				.type	= cpu_to_fdt32(GIC_FDT_IRQ_TYPE_SPI),
 				.num	= cpu_to_fdt32(irq - GIC_SPI_IRQ_BASE),
-				.flags	= cpu_to_fdt32(IRQ_TYPE_EDGE_RISING),
+				.flags	= cpu_to_fdt32(irq_flags),
 			},
 		};
 

include/kvm/pci.h

@@ -9,6 +9,7 @@
 #include "kvm/devices.h"
 #include "kvm/kvm.h"
 #include "kvm/msi.h"
+#include "kvm/fdt.h"
 
 /*
  * PCI Configuration Mechanism #1 I/O ports. See Section 3.7.4.1.
@@ -105,6 +106,11 @@ struct pci_device_header {
 	/* Private to lkvm */
 	u32		bar_size[6];
 	struct pci_config_operations	cfg_ops;
+	/*
+	 * PCI INTx# are level-triggered, but virtual device often feature
+	 * edge-triggered INTx# for convenience.
+	 */
+	enum irq_type	irq_type;
 };
 
 int pci__init(struct kvm *kvm);

pci.c

@@ -39,6 +39,9 @@ void pci__assign_irq(struct device_header *dev_hdr)
 	 */
 	pci_hdr->irq_pin	= 1;
 	pci_hdr->irq_line	= irq__alloc_line();
+
+	if (!pci_hdr->irq_type)
+		pci_hdr->irq_type = IRQ_TYPE_EDGE_RISING;
 }
 
 static void *pci_config_address_ptr(u16 port)