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[Qemu-devel] [PATCH 2/2] virtio-pci: fallback to userspace when there is
From: |
Amos Kong |
Subject: |
[Qemu-devel] [PATCH 2/2] virtio-pci: fallback to userspace when there is no enough available ioeventfd |
Date: |
Tue, 13 Mar 2012 18:42:40 +0800 |
User-agent: |
StGit/0.15 |
Qemu already supported multiple function devices, pci-bridge
would support more pci devices. But iobus dev in kernel are
limited. If there is no enough available ioeventfd, then
clean VIRTIO_PCI_FLAG_USE_IOEVENTFD bit, virtio-pci would
fallback to userspace.
Signed-off-by: Amos Kong <address@hidden>
---
hw/virtio-pci.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index d63f303..d15b11b 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -322,6 +322,9 @@ static void virtio_ioport_write(void *opaque, uint32_t
addr, uint32_t val)
virtio_set_status(vdev, val & 0xFF);
if (val & VIRTIO_CONFIG_S_DRIVER_OK) {
+ if (kvm_has_many_ioeventfds() == 0) {
+ proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
+ }
virtio_pci_start_ioeventfd(proxy);
}
Re: [Qemu-devel] [PATCH 0/2] virtio-pci: fix abort when fail to allocate ioeventfd, Stefan Hajnoczi, 2012/03/13