[PATCH V6 20/27] vfio-pci: cpr part 2 (msi)

[Steve Sistare]

Finish cpr for vfio-pci MSI/MSI-X devices by preserving eventfd's and
vector state.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 hw/vfio/pci.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 1 deletion(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 64e2557..1cee52a 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -49,11 +49,31 @@
 static void vfio_disable_interrupts(VFIOPCIDevice *vdev);
 static void vfio_mmap_set_enabled(VFIOPCIDevice *vdev, bool enabled);
 
+static void save_event_fd(VFIOPCIDevice *vdev, const char *name, int nr,
+                          EventNotifier *ev)
+{
+    int fd = event_notifier_get_fd(ev);
+
+    if (fd >= 0) {
+        g_autofree char *fdname =
+            g_strdup_printf("%s_%s", vdev->vbasedev.name, name);
+        cpr_save_fd(fdname, nr, fd);
+    }
+}
+
+static int load_event_fd(VFIOPCIDevice *vdev, const char *name, int nr)
+{
+    g_autofree char *fdname =
+        g_strdup_printf("%s_%s", vdev->vbasedev.name, name);
+    int fd = cpr_find_fd(fdname, nr);
+    return fd;
+}
+
 /* Create new or reuse existing eventfd */
 static int vfio_named_notifier_init(VFIOPCIDevice *vdev, EventNotifier *e,
                                     const char *name, int nr)
 {
-    int fd = -1;   /* placeholder until a subsequent patch */
+    int fd = name ? load_event_fd(vdev, name, nr) : -1;
 
     if (fd >= 0) {
         event_notifier_init_fd(e, fd);
@@ -2709,6 +2729,10 @@ static void vfio_register_err_notifier(VFIOPCIDevice 
*vdev)
     fd = event_notifier_get_fd(&vdev->err_notifier);
     qemu_set_fd_handler(fd, vfio_err_notifier_handler, NULL, vdev);
 
+    if (vdev->pdev.reused) {
+        return;
+    }
+
     if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_ERR_IRQ_INDEX, 0,
                                VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
         error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
@@ -2774,6 +2798,11 @@ static void vfio_register_req_notifier(VFIOPCIDevice 
*vdev)
     fd = event_notifier_get_fd(&vdev->req_notifier);
     qemu_set_fd_handler(fd, vfio_req_notifier_handler, NULL, vdev);
 
+    if (vdev->pdev.reused) {
+        vdev->req_enabled = true;
+        return;
+    }
+
     if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_REQ_IRQ_INDEX, 0,
                            VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
         error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
@@ -3302,13 +3331,87 @@ static void vfio_merge_config(VFIOPCIDevice *vdev)
     }
 }
 
+static int vfio_pci_pre_save(void *opaque)
+{
+    VFIOPCIDevice *vdev = opaque;
+    PCIDevice *pdev = &vdev->pdev;
+    int i;
+
+    if (vfio_pci_read_config(pdev, PCI_INTERRUPT_PIN, 1)) {
+        assert(0);      /* completed in a subsequent patch */
+    }
+
+    for (i = 0; i < vdev->nr_vectors; i++) {
+        VFIOMSIVector *vector = &vdev->msi_vectors[i];
+        if (vector->use) {
+            save_event_fd(vdev, "interrupt", i, &vector->interrupt);
+            if (vector->virq >= 0) {
+                save_event_fd(vdev, "kvm_interrupt", i,
+                                &vector->kvm_interrupt);
+            }
+        }
+    }
+    save_event_fd(vdev, "err", 0, &vdev->err_notifier);
+    save_event_fd(vdev, "req", 0, &vdev->req_notifier);
+    return 0;
+}
+
+static void vfio_claim_vectors(VFIOPCIDevice *vdev, int nr_vectors, bool msix)
+{
+    int i, fd;
+    bool pending = false;
+    PCIDevice *pdev = &vdev->pdev;
+
+    vdev->nr_vectors = nr_vectors;
+    vdev->msi_vectors = g_new0(VFIOMSIVector, nr_vectors);
+    vdev->interrupt = msix ? VFIO_INT_MSIX : VFIO_INT_MSI;
+
+    for (i = 0; i < nr_vectors; i++) {
+        VFIOMSIVector *vector = &vdev->msi_vectors[i];
+
+        fd = load_event_fd(vdev, "interrupt", i);
+        if (fd >= 0) {
+            vfio_vector_init(vdev, "interrupt", i);
+            qemu_set_fd_handler(fd, vfio_msi_interrupt, NULL, vector);
+        }
+
+        if (load_event_fd(vdev, "kvm_interrupt", i) >= 0) {
+            vfio_add_kvm_msi_virq(vdev, vector, "kvm_interrupt", i, msix);
+        }
+
+        if (msix && msix_is_pending(pdev, i) && msix_is_masked(pdev, i)) {
+            set_bit(i, vdev->msix->pending);
+            pending = true;
+        }
+    }
+
+    if (msix) {
+        memory_region_set_enabled(&pdev->msix_pba_mmio, pending);
+    }
+}
+
 static int vfio_pci_post_load(void *opaque, int version_id)
 {
     VFIOPCIDevice *vdev = opaque;
     PCIDevice *pdev = &vdev->pdev;
+    int nr_vectors;
 
     vfio_merge_config(vdev);
 
+    if (msix_enabled(pdev)) {
+        nr_vectors = vdev->msix->entries;
+        vfio_claim_vectors(vdev, nr_vectors, true);
+        msix_init_vector_notifiers(pdev, vfio_msix_vector_use,
+                                   vfio_msix_vector_release, NULL);
+
+    } else if (msi_enabled(pdev)) {
+        nr_vectors = msi_nr_vectors_allocated(pdev);
+        vfio_claim_vectors(vdev, nr_vectors, false);
+
+    } else if (vfio_pci_read_config(pdev, PCI_INTERRUPT_PIN, 1)) {
+        assert(0);      /* completed in a subsequent patch */
+    }
+
     pdev->reused = false;
 
     return 0;
@@ -3325,8 +3428,11 @@ static const VMStateDescription vfio_pci_vmstate = {
     .version_id = 0,
     .minimum_version_id = 0,
     .post_load = vfio_pci_post_load,
+    .pre_save = vfio_pci_pre_save,
     .needed = vfio_pci_needed,
     .fields = (VMStateField[]) {
+        VMSTATE_PCI_DEVICE(pdev, VFIOPCIDevice),
+        VMSTATE_MSIX_TEST(pdev, VFIOPCIDevice, vfio_msix_present),
         VMSTATE_END_OF_LIST()
     }
 };
-- 
1.8.3.1