[Qemu-devel] [PATCH uq/master 4/9] ivshmem: use EventNotifier and memory API

[Paolo Bonzini <pbonzini@redhat.com>]

All of ivshmem's usage of eventfd now has a corresponding API in
EventNotifier.  Simplify the code by using it, and also use the
memory API consistently to set up and tear down the ioeventfds.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/ivshmem.c |   63 ++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 35 insertions(+), 28 deletions(-)

diff --git a/hw/ivshmem.c b/hw/ivshmem.c
index 05559b6..3cdbea2 100644
--- a/hw/ivshmem.c
+++ b/hw/ivshmem.c
@@ -23,6 +23,7 @@
 #include "kvm.h"
 #include "migration.h"
 #include "qerror.h"
+#include "event_notifier.h"
 
 #include <sys/mman.h>
 #include <sys/types.h>
@@ -45,7 +46,7 @@
 
 typedef struct Peer {
     int nb_eventfds;
-    int *eventfds;
+    EventNotifier *eventfds;
 } Peer;
 
 typedef struct EventfdEntry {
@@ -63,7 +64,6 @@ typedef struct IVShmemState {
     CharDriverState *server_chr;
     MemoryRegion ivshmem_mmio;
 
-    pcibus_t mmio_addr;
     /* We might need to register the BAR before we actually have the memory.
      * So prepare a container MemoryRegion for the BAR immediately and
      * add a subregion when we have the memory.
@@ -168,7 +168,6 @@ static void ivshmem_io_write(void *opaque, target_phys_addr_t addr,
 {
     IVShmemState *s = opaque;
 
-    uint64_t write_one = 1;
     uint16_t dest = val >> 16;
     uint16_t vector = val & 0xff;
 
@@ -194,12 +193,8 @@ static void ivshmem_io_write(void *opaque, target_phys_addr_t addr,
 
             /* check doorbell range */
             if (vector < s->peers[dest].nb_eventfds) {
-                IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on vector %d\n",
-                                                    write_one, dest, vector);
-                if (write(s->peers[dest].eventfds[vector],
-                                                    &(write_one), 8) != 8) {
-                    IVSHMEM_DPRINTF("error writing to eventfd\n");
-                }
+                IVSHMEM_DPRINTF("Notifying VM %d on vector %d\n", dest, vector);
+                event_notifier_set(&s->peers[dest].eventfds[vector]);
             }
             break;
         default:
@@ -279,12 +274,13 @@ static void fake_irqfd(void *opaque, const uint8_t *buf, int size) {
     msix_notify(pdev, entry->vector);
 }
 
-static CharDriverState* create_eventfd_chr_device(void * opaque, int eventfd,
-                                                                    int vector)
+static CharDriverState* create_eventfd_chr_device(void * opaque, EventNotifier *n,
+                                                  int vector)
 {
     /* create a event character device based on the passed eventfd */
     IVShmemState *s = opaque;
     CharDriverState * chr;
+    int eventfd = event_notifier_get_fd(n);
 
     chr = qemu_chr_open_eventfd(eventfd);
 
@@ -347,6 +343,26 @@ static void create_shared_memory_BAR(IVShmemState *s, int fd) {
     pci_register_bar(&s->dev, 2, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar);
 }
 
+static void ivshmem_add_eventfd(IVShmemState *s, int posn, int i)
+{
+    memory_region_add_eventfd(&s->ivshmem_mmio,
+                              DOORBELL,
+                              4,
+                              true,
+                              (posn << 16) | i,
+                              event_notifier_get_fd(&s->peers[posn].eventfds[i]));
+}
+
+static void ivshmem_del_eventfd(IVShmemState *s, int posn, int i)
+{
+    memory_region_del_eventfd(&s->ivshmem_mmio,
+                              DOORBELL,
+                              4,
+                              true,
+                              (posn << 16) | i,
+                              event_notifier_get_fd(&s->peers[posn].eventfds[i]));
+}
+
 static void close_guest_eventfds(IVShmemState *s, int posn)
 {
     int i, guest_curr_max;
@@ -354,9 +370,8 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
     guest_curr_max = s->peers[posn].nb_eventfds;
 
     for (i = 0; i < guest_curr_max; i++) {
-        kvm_set_ioeventfd_mmio(s->peers[posn].eventfds[i],
-                    s->mmio_addr + DOORBELL, (posn << 16) | i, 0, 4);
-        close(s->peers[posn].eventfds[i]);
+        ivshmem_del_eventfd(s, posn, i);
+        event_notifier_cleanup(&s->peers[posn].eventfds[i]);
     }
 
     g_free(s->peers[posn].eventfds);
@@ -369,12 +384,7 @@ static void setup_ioeventfds(IVShmemState *s) {
 
     for (i = 0; i <= s->max_peer; i++) {
         for (j = 0; j < s->peers[i].nb_eventfds; j++) {
-            memory_region_add_eventfd(&s->ivshmem_mmio,
-                                      DOORBELL,
-                                      4,
-                                      true,
-                                      (i << 16) | j,
-                                      s->peers[i].eventfds[j]);
+            ivshmem_add_eventfd(s, i, j);
         }
     }
 }
@@ -476,14 +486,14 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
 
     if (guest_max_eventfd == 0) {
         /* one eventfd per MSI vector */
-        s->peers[incoming_posn].eventfds = (int *) g_malloc(s->vectors *
-                                                                sizeof(int));
+        s->peers[incoming_posn].eventfds = g_new(EventNotifier, s->vectors);
     }
 
     /* this is an eventfd for a particular guest VM */
     IVSHMEM_DPRINTF("eventfds[%ld][%d] = %d\n", incoming_posn,
                                             guest_max_eventfd, incoming_fd);
-    s->peers[incoming_posn].eventfds[guest_max_eventfd] = incoming_fd;
+    event_notifier_init_fd(&s->peers[incoming_posn].eventfds[guest_max_eventfd],
+                           incoming_fd);
 
     /* increment count for particular guest */
     s->peers[incoming_posn].nb_eventfds++;
@@ -495,15 +505,12 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
 
     if (incoming_posn == s->vm_id) {
         s->eventfd_chr[guest_max_eventfd] = create_eventfd_chr_device(s,
-                   s->peers[s->vm_id].eventfds[guest_max_eventfd],
+                   &s->peers[s->vm_id].eventfds[guest_max_eventfd],
                    guest_max_eventfd);
     }
 
     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
-        if (kvm_set_ioeventfd_mmio(incoming_fd, s->mmio_addr + DOORBELL,
-                        (incoming_posn << 16) | guest_max_eventfd, 1, 4) < 0) {
-            fprintf(stderr, "ivshmem: ioeventfd not available\n");
-        }
+        ivshmem_add_eventfd(s, incoming_posn, guest_max_eventfd);
     }
 
     return;
-- 
1.7.10.2