Commit c324fd0a authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

virtio-pci: use ioeventfd even when KVM is disabled 



Old kvm.ko versions only supported a tiny number of ioeventfds so
virtio-pci avoids ioeventfds when kvm_has_many_ioeventfds() returns 0.

Do not check kvm_has_many_ioeventfds() when KVM is disabled since it
always returns 0.  Since commit 8c56c1a5
("memory: emulate ioeventfd") it has been possible to use ioeventfds in
qtest or TCG mode.

This patch makes -device virtio-blk-pci,iothread=iothread0 work even
when KVM is disabled.

I have tested that virtio-blk-pci works under TCG both with and without
iothread.

This patch fixes qemu-iotests 068, which was accidentally merged early
despite the dependency on ioeventfd.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Tested-by: default avatarEric Blake <eblake@redhat.com>
Tested-by: default avatarKevin Wolf <kwolf@redhat.com>
Message-id: 20170628184724.21378-7-stefanha@redhat.com
Message-id: 20170615163813.7255-2-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 8e11c9d3

hw/virtio/virtio-pci.c

+1 −1
Original line number Diff line number Diff line
@@ -1740,7 +1740,7 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp) 
    bool pcie_port = pci_bus_is_express(pci_dev->bus) &&

                     !pci_bus_is_root(pci_dev->bus);



    if (!kvm_has_many_ioeventfds()) {

    if (kvm_enabled() && !kvm_has_many_ioeventfds()) {

        proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;

    }