[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 2/3] ivshmem: Always remove irqfd notifiers
From: |
Ladi Prosek |
Subject: |
[Qemu-devel] [PATCH 2/3] ivshmem: Always remove irqfd notifiers |
Date: |
Fri, 10 Nov 2017 18:34:20 +0100 |
As of commit 660c97eef6f8 ("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: 660c97eef6f8 ("ivshmem: use kvm irqfd for msi notifications")
Signed-off-by: Ladi Prosek <address@hidden>
---
hw/misc/ivshmem.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 6e46669744..493a5030a1 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -77,6 +77,7 @@ typedef struct Peer {
typedef struct MSIVector {
PCIDevice *pdev;
int virq;
+ bool unmasked;
} MSIVector;
typedef struct IVShmemState {
@@ -321,6 +322,7 @@ 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) {
@@ -328,7 +330,11 @@ 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) {
+ v->unmasked = true;
+ }
+ return ret;
}
static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector)
@@ -343,9 +349,12 @@ 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) {
+ v->unmasked = false;
+ } else {
error_report("remove_irqfd_notifier_gsi failed");
}
}
@@ -817,11 +826,20 @@ static void ivshmem_disable_irqfd(IVShmemState *s)
PCIDevice *pdev = PCI_DEVICE(s);
int i;
- for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
- ivshmem_remove_kvm_msi_virq(s, 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);
+ }
+
}
static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
--
2.13.5