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ivshmem: Improve MSI irqfd error handling

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Adds a rollback path to ivshmem_enable_irqfd() and fixes
ivshmem_disable_irqfd() to bail if irqfd has not been enabled.

To reproduce, run:

  ivshmem-server -n 0

and QEMU with:

  -device ivshmem-doorbell,chardev=iv
  -chardev socket,path=/tmp/ivshmem_socket,id=iv

then load, unload, and load again the Windows driver, at the time of writing
available at:

https://github.com/virtio-win/kvm-guest-drivers-windows/tree/master/ivshmem

The issue is believed to have been masked by other guest drivers, notably
Linux ones, not enabling MSI-X on the device.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20171211072110.9058-4-lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ladi Prosek 2017-12-11 08:21:09 +01:00 committed by Paolo Bonzini
parent 089fd80376
commit 0b88dd9420
1 changed files with 34 additions and 23 deletions
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57
hw/misc/ivshmem.c
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@ -785,29 +785,6 @@ static int ivshmem_setup_interrupts(IVShmemState *s, Error **errp)
return 0;
}
static void ivshmem_enable_irqfd(IVShmemState *s)
{
PCIDevice *pdev = PCI_DEVICE(s);
int i;
for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
Error *err = NULL;
ivshmem_add_kvm_msi_virq(s, i, &err);
if (err) {
error_report_err(err);
/* TODO do we need to handle the error? */
}
}
if (msix_set_vector_notifiers(pdev,
ivshmem_vector_unmask,
ivshmem_vector_mask,
ivshmem_vector_poll)) {
error_report("ivshmem: msix_set_vector_notifiers failed");
}
}
static void ivshmem_remove_kvm_msi_virq(IVShmemState *s, int vector)
{
IVSHMEM_DPRINTF("ivshmem_remove_kvm_msi_virq vector:%d\n", vector);
@ -822,11 +799,45 @@ static void ivshmem_remove_kvm_msi_virq(IVShmemState *s, int vector)
s->msi_vectors[vector].pdev = NULL;
}
static void ivshmem_enable_irqfd(IVShmemState *s)
{
PCIDevice *pdev = PCI_DEVICE(s);
int i;
for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
Error *err = NULL;
ivshmem_add_kvm_msi_virq(s, i, &err);
if (err) {
error_report_err(err);
goto undo;
}
}
if (msix_set_vector_notifiers(pdev,
ivshmem_vector_unmask,
ivshmem_vector_mask,
ivshmem_vector_poll)) {
error_report("ivshmem: msix_set_vector_notifiers failed");
goto undo;
}
return;
undo:
while (--i >= 0) {
ivshmem_remove_kvm_msi_virq(s, i);
}
}
static void ivshmem_disable_irqfd(IVShmemState *s)
{
PCIDevice *pdev = PCI_DEVICE(s);
int i;
if (!pdev->msix_vector_use_notifier) {
return;
}
msix_unset_vector_notifiers(pdev);
for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {