Re: [libvirt] [PATCH] device-assignment: Reset device on system reset
* Alex Williamson (alex.williamson@redhat.com) wrote:
static void reset_assigned_device(DeviceState *dev) { - PCIDevice *d = DO_UPCAST(PCIDevice, qdev, dev); + PCIDevice *pci_dev = DO_UPCAST(PCIDevice, qdev, dev); + 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/0000:%02x:%02x.%01x/reset", + adev->host.bus, adev->host.dev, adev->host.func);
need to consider segment: %04x:..., adev->host.seg, ...
+ /* + * 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); + }
This will probably fail when it's managed by libvirt. I expect it will need some file ownership and security label mgmt added to device assignement path I expect.
On Thu, 2011-03-17 at 14:12 -0700, Chris Wright wrote:
* Alex Williamson (alex.williamson@redhat.com) wrote:
static void reset_assigned_device(DeviceState *dev) { - PCIDevice *d = DO_UPCAST(PCIDevice, qdev, dev); + PCIDevice *pci_dev = DO_UPCAST(PCIDevice, qdev, dev); + 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/0000:%02x:%02x.%01x/reset", + adev->host.bus, adev->host.dev, adev->host.func);
need to consider segment: %04x:..., adev->host.seg, ...
Shoot, I ported this over from a code base w/o seg support. Thanks for the catch.
+ /* + * 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); + }
This will probably fail when it's managed by libvirt. I expect it will need some file ownership and security label mgmt added to device assignement path I expect.
Already posted a patch for adding file rights, seems to be sufficient: https://www.redhat.com/archives/libvir-list/2011-March/msg00823.html Thanks, Alex
* Alex Williamson (alex.williamson@redhat.com) wrote:
On Thu, 2011-03-17 at 14:12 -0700, Chris Wright wrote:
* Alex Williamson (alex.williamson@redhat.com) wrote:
+ fd = open(reset_file, O_WRONLY); + if (fd != -1) { + ret = write(fd, reset, strlen(reset)); + close(fd); + }
This will probably fail when it's managed by libvirt. I expect it will need some file ownership and security label mgmt added to device assignement path I expect.
Already posted a patch for adding file rights, seems to be sufficient:
https://www.redhat.com/archives/libvir-list/2011-March/msg00823.html
Awesome, I missed that path, thanks Alex! thanks, -chris
participants (2)
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Alex Williamson -
Chris Wright