From patchwork Fri Dec 16 01:14:26 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: virtio-serial: Allow one MSI-X vector per virtqueue Date: Thu, 15 Dec 2011 15:14:26 -0000 From: zanghongyong@huawei.com X-Patchwork-Id: 131768 Message-Id: <1323998066-2396-1-git-send-email-zanghongyong@huawei.com> To: qemu-devel@nongnu.org Cc: aliguori@us.ibm.com, wusongwei@huawei.com, kvm@vger.kernel.org, hanweidong@huawei.com, rusty@rustcorp.com.au, xiaowei.yang@huawei.com, Hongyong Zang , jiangningyu@huawei.com, amit.shah@redhat.com From: Hongyong Zang In pci_enable_msix(), the guest's virtio-serial driver tries to set msi-x with one vector per queue. But it fails and eventually all virtio-serial ports share one MSI-X vector. Because every virtio-serial port has *two* virtqueues, virtio-serial needs (port+1)*2 vectors other than (port+1). This patch allows every virtqueue to have its own MSI-X vector. (When the MSI-X vectors needed are more than MSIX_MAX_ENTRIES defined in qemu: msix.c, all the queues still share one MSI-X vector as before.) Signed-off-by: Hongyong Zang --- hw/virtio-pci.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c index 77b75bc..2c9c6fb 100644 --- a/hw/virtio-pci.c +++ b/hw/virtio-pci.c @@ -718,8 +718,11 @@ static int virtio_serial_init_pci(PCIDevice *pci_dev) return -1; } vdev->nvectors = proxy->nvectors == DEV_NVECTORS_UNSPECIFIED - ? proxy->serial.max_virtserial_ports + 1 + ? (proxy->serial.max_virtserial_ports + 1) * 2 : proxy->nvectors; + /*msix.c: #define MSIX_MAX_ENTRIES 32*/ + if (vdev->nvectors > 32) + vdev->nvectors = 32; virtio_init_pci(proxy, vdev); proxy->nvectors = vdev->nvectors; return 0;