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ivshmem: Always remove irqfd notifiers

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As of commit 660c97eef6 ("ivshmem: use kvm irqfd for msi notifications"),
QEMU crashes with:

ivshmem: msix_set_vector_notifiers failed
msix_unset_vector_notifiers: Assertion `dev->msix_vector_use_notifier && dev->msix_vector_release_notifier' failed.

if MSI-X is repeatedly enabled and disabled on the ivshmem device, for example
by loading and unloading the Windows ivshmem driver. This is because
msix_unset_vector_notifiers() doesn't call any of the release notifier callbacks
since MSI-X is already disabled at that point (msix_enabled() returning false
is how this transition is detected in the first place). Thus ivshmem_vector_mask()
doesn't run and when MSI-X is subsequently enabled again ivshmem_vector_unmask()
fails.

This is fixed by keeping track of unmasked vectors and making sure that
ivshmem_vector_mask() always runs on MSI-X disable.

Fixes: 660c97eef6 ("ivshmem: use kvm irqfd for msi notifications")
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20171211072110.9058-3-lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ladi Prosek 2017-12-11 08:21:08 +01:00 committed by Paolo Bonzini
parent e6a354be6e
commit 089fd80376
1 changed files with 23 additions and 3 deletions
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26
hw/misc/ivshmem.c
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@ -76,6 +76,7 @@ typedef struct Peer {
typedef struct MSIVector {
PCIDevice *pdev;
int virq;
bool unmasked;
} MSIVector;
typedef struct IVShmemState {
@ -320,6 +321,7 @@ static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector,
error_report("ivshmem: vector %d route does not exist", vector);
return -EINVAL;
}
assert(!v->unmasked);
ret = kvm_irqchip_update_msi_route(kvm_state, v->virq, msg, dev);
if (ret < 0) {
@ -327,7 +329,13 @@ static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector,
}
kvm_irqchip_commit_routes(kvm_state);
return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, v->virq);
ret = kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, v->virq);
if (ret < 0) {
return ret;
}
v->unmasked = true;
return 0;
}
static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector)
@ -342,11 +350,14 @@ static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector)
error_report("ivshmem: vector %d route does not exist", vector);
return;
}
assert(v->unmasked);
ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, v->virq);
if (ret != 0) {
if (ret < 0) {
error_report("remove_irqfd_notifier_gsi failed");
return;
}
v->unmasked = false;
}
static void ivshmem_vector_poll(PCIDevice *dev,
@ -816,11 +827,20 @@ static void ivshmem_disable_irqfd(IVShmemState *s)
PCIDevice *pdev = PCI_DEVICE(s);
int i;
msix_unset_vector_notifiers(pdev);
for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
/*
* MSI-X is already disabled here so msix_unset_vector_notifiers()
* didn't call our release notifier. Do it now to keep our masks and
* unmasks balanced.
*/
if (s->msi_vectors[i].unmasked) {
ivshmem_vector_mask(pdev, i);
}
ivshmem_remove_kvm_msi_virq(s, i);
}
msix_unset_vector_notifiers(pdev);
}
static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,