hw/vfio/platform: add irq assignment

This patch adds the code requested to assign interrupts to
a guest. The interrupts are mediated through user handled
eventfds only.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Vikram Sethi <vikrams@codeaurora.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

include/hw/vfio/vfio-platform.h

@@ -18,14 +18,45 @@
 
 #include "hw/sysbus.h"
 #include "hw/vfio/vfio-common.h"
+#include "qemu/event_notifier.h"
+#include "qemu/queue.h"
+#include "hw/irq.h"
 
 #define TYPE_VFIO_PLATFORM "vfio-platform"
 
+enum {
+    VFIO_IRQ_INACTIVE = 0,
+    VFIO_IRQ_PENDING = 1,
+    VFIO_IRQ_ACTIVE = 2,
+    /* VFIO_IRQ_ACTIVE_AND_PENDING cannot happen with VFIO */
+};
+
+typedef struct VFIOINTp {
+    QLIST_ENTRY(VFIOINTp) next; /* entry for IRQ list */
+    QSIMPLEQ_ENTRY(VFIOINTp) pqnext; /* entry for pending IRQ queue */
+    EventNotifier interrupt; /* eventfd triggered on interrupt */
+    EventNotifier unmask; /* eventfd for unmask on QEMU bypass */
+    qemu_irq qemuirq;
+    struct VFIOPlatformDevice *vdev; /* back pointer to device */
+    int state; /* inactive, pending, active */
+    uint8_t pin; /* index */
+    uint32_t flags; /* IRQ info flags */
+} VFIOINTp;
+
+/* function type for user side eventfd handler */
+typedef void (*eventfd_user_side_handler_t)(VFIOINTp *intp);
+
 typedef struct VFIOPlatformDevice {
     SysBusDevice sbdev;
     VFIODevice vbasedev; /* not a QOM object */
     VFIORegion **regions;
+    QLIST_HEAD(, VFIOINTp) intp_list; /* list of IRQs */
+    /* queue of pending IRQs */
+    QSIMPLEQ_HEAD(pending_intp_queue, VFIOINTp) pending_intp_queue;
     char *compat; /* compatibility string */
+    uint32_t mmap_timeout; /* delay to re-enable mmaps after interrupt */
+    QEMUTimer *mmap_timer; /* allows fast-path resume after IRQ hit */
+    QemuMutex intp_mutex; /* protect the intp_list IRQ state */
 } VFIOPlatformDevice;
 
 typedef struct VFIOPlatformDeviceClass {

trace-events

@@ -1568,6 +1568,13 @@ vfio_put_base_device(int fd) "close vdev->fd=%d"
 vfio_platform_populate_regions(int region_index, unsigned long flag, unsigned long size, int fd, unsigned long offset) "- region %d flags = 0x%lx, size = 0x%lx, fd= %d, offset = 0x%lx"
 vfio_platform_base_device_init(char *name, int groupid) "%s belongs to group #%d"
 vfio_platform_realize(char *name, char *compat) "vfio device %s, compat = %s"
+vfio_platform_eoi(int pin, int fd) "EOI IRQ pin %d (fd=%d)"
+vfio_platform_mmap_set_enabled(bool enabled) "fast path = %d"
+vfio_platform_intp_mmap_enable(int pin) "IRQ #%d still active, stay in slow path"
+vfio_platform_intp_interrupt(int pin, int fd) "Inject IRQ #%d (fd = %d)"
+vfio_platform_intp_inject_pending_lockheld(int pin, int fd) "Inject pending IRQ #%d (fd = %d)"
+vfio_platform_populate_interrupts(int pin, int count, int flags) "- IRQ index %d: count %d, flags=0x%x"
+vfio_intp_interrupt_set_pending(int index) "irq %d is set PENDING"
 
 #hw/acpi/memory_hotplug.c
 mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32