On Wed, 2010-05-19 at 12:00 -0700, Chris Wright wrote: > When libvirt launches a guest it first chowns the relevenat > /sys/bus/pci/.../config file for an assigned device then drops privileges. > > This causes an issue for device assignment because despite being file > owner, the sysfs config space file checks for CAP_SYS_ADMIN before > allowing access to device dependent config space. > > This adds a new qdev configfd property which allows libvirt to open the > sysfs config space file and give qemu an already opened file descriptor. > Along with a change pending for the 2.6.35 kernel, this allows the > capability check to compare against privileges from when the file was > opened. We need to make configfd be a string option so that we can pass a descriptor from libvirt for the hotplug case. Here's a rework. Signed-off-by: Chris Wright <chrisw@xxxxxxxxxx> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> --- diff --git a/hw/device-assignment.c b/hw/device-assignment.c index eb31c78..3c5184f 100644 --- a/hw/device-assignment.c +++ b/hw/device-assignment.c @@ -37,6 +37,7 @@ #include "console.h" #include "device-assignment.h" #include "loader.h" +#include "monitor.h" #include <pci/pci.h> /* From linux/ioport.h */ @@ -612,14 +613,28 @@ static int get_real_device(AssignedDevice *pci_dev, uint16_t r_seg, snprintf(name, sizeof(name), "%sconfig", dir); - fd = open(name, O_RDWR); - if (fd == -1) { - fprintf(stderr, "%s: %s: %m\n", __func__, name); - return 1; + if (pci_dev->configfd_name && *pci_dev->configfd_name) { + if (qemu_isdigit(pci_dev->configfd_name[0])) { + dev->config_fd = strtol(pci_dev->configfd_name, NULL, 0); + } else { + dev->config_fd = monitor_get_fd(cur_mon, pci_dev->configfd_name); + if (dev->config_fd < 0) { + fprintf(stderr, "%s: (%s) unkown\n", __func__, + pci_dev->configfd_name); + return 1; + } + } + } else { + dev->config_fd = open(name, O_RDWR); + + if (dev->config_fd == -1) { + fprintf(stderr, "%s: %s: %m\n", __func__, name); + return 1; + } } - dev->config_fd = fd; again: - r = read(fd, pci_dev->dev.config, pci_config_size(&pci_dev->dev)); + r = read(dev->config_fd, pci_dev->dev.config, + pci_config_size(&pci_dev->dev)); if (r < 0) { if (errno == EINTR || errno == EAGAIN) goto again; @@ -1433,6 +1448,7 @@ static PCIDeviceInfo assign_info = { .qdev.props = (Property[]) { DEFINE_PROP("host", AssignedDevice, host, qdev_prop_hostaddr, PCIHostDevice), DEFINE_PROP_UINT32("iommu", AssignedDevice, use_iommu, 1), + DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name), DEFINE_PROP_END_OF_LIST(), }, }; diff --git a/hw/device-assignment.h b/hw/device-assignment.h index d561112..f70ace9 100644 --- a/hw/device-assignment.h +++ b/hw/device-assignment.h @@ -104,6 +104,7 @@ typedef struct AssignedDevice { target_phys_addr_t msix_table_addr; int mmio_index; int need_emulate_cmd; + char *configfd_name; QLIST_ENTRY(AssignedDevice) next; } AssignedDevice; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html