On 05/19/2010 02:00 PM, 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.
Signed-off-by: Chris Wright<chrisw@xxxxxxxxxx>
An fd as a qdev property seems like a bad idea to me. I'm not sure I
have a better suggestion though.
Regards,
Anthony Liguori
---
hw/device-assignment.c | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index eb31c78..172f0c9 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -612,12 +612,15 @@ static int get_real_device(AssignedDevice *pci_dev, uint16_t r_seg,
snprintf(name, sizeof(name), "%sconfig", dir);
- fd = open(name, O_RDWR);
+ fd = dev->config_fd;
if (fd == -1) {
- fprintf(stderr, "%s: %s: %m\n", __func__, name);
- return 1;
+ fd = open(name, O_RDWR);
+ if (fd == -1) {
+ fprintf(stderr, "%s: %s: %m\n", __func__, name);
+ return 1;
+ }
+ dev->config_fd = fd;
}
- dev->config_fd = fd;
again:
r = read(fd, pci_dev->dev.config, pci_config_size(&pci_dev->dev));
if (r< 0) {
@@ -1433,6 +1436,7 @@ 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_INT32("configfd", AssignedDevice, real_device.config_fd, -1),
DEFINE_PROP_END_OF_LIST(),
},
};
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