From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: [PATCH] pci-assign: Do not reset the device unless the kernel supports it Date: Mon, 06 Jun 2011 23:30:55 +0200 Message-ID: <4DED470F.4020203@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: kvm , Alex Williamson To: Avi Kivity , Marcelo Tosatti Return-path: Received: from fmmailgate03.web.de ([217.72.192.234]:56134 "EHLO fmmailgate03.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752500Ab1FFVcS (ORCPT ); Mon, 6 Jun 2011 17:32:18 -0400 Sender: kvm-owner@vger.kernel.org List-ID: From: Jan Kiszka At least kernels 2.6.38 and 2.6.39 do not properly support issuing a reset on an assigned device and corrupt its config space. Prevent this by checking for a host kernel with the required support, tagged by the to-be-introduced KVM_CAP_DEVICE_RESET. Signed-off-by: Jan Kiszka --- PS: What's the state of those KVM patches? Will they make it into 3.0? hw/device-assignment.c | 33 +++++++++++++++++++-------------- 1 files changed, 19 insertions(+), 14 deletions(-) diff --git a/hw/device-assignment.c b/hw/device-assignment.c index 57d8dc0..97a1450 100644 --- a/hw/device-assignment.c +++ b/hw/device-assignment.c @@ -1689,26 +1689,31 @@ static const VMStateDescription vmstate_assigned_device = { static void reset_assigned_device(DeviceState *dev) { PCIDevice *pci_dev = DO_UPCAST(PCIDevice, qdev, dev); +#ifdef KVM_CAP_DEVICE_RESET AssignedDevice *adev = DO_UPCAST(AssignedDevice, dev, pci_dev); char reset_file[64]; const char reset[] = "1"; int fd, ret; - snprintf(reset_file, sizeof(reset_file), - "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/reset", - adev->host.seg, adev->host.bus, adev->host.dev, adev->host.func); - - /* - * Issue a device reset via pci-sysfs. Note that we use write(2) here - * and ignore the return value because some kernels have a bug that - * returns 0 rather than bytes written on success, sending us into an - * infinite retry loop using other write mechanisms. - */ - fd = open(reset_file, O_WRONLY); - if (fd != -1) { - ret = write(fd, reset, strlen(reset)); - close(fd); + if (kvm_check_extension(kvm_state, KVM_CAP_DEVICE_RESET) { + snprintf(reset_file, sizeof(reset_file), + "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/reset", + adev->host.seg, adev->host.bus, adev->host.dev, + adev->host.func); + + /* + * Issue a device reset via pci-sysfs. Note that we use write(2) here + * and ignore the return value because some kernels have a bug that + * returns 0 rather than bytes written on success, sending us into an + * infinite retry loop using other write mechanisms. + */ + fd = open(reset_file, O_WRONLY); + if (fd != -1) { + ret = write(fd, reset, strlen(reset)); + close(fd); + } } +#endif /* KVM_CAP_DEVICE_RESET */ /* * When a 0 is written to the command register, the device is logically