From: Chris Wright <chr...@redhat.com>
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.
[alex.williamson: make configfd be a string option so that we can pass a
descriptor from libvirt for the hotplug case]
Signed-off-by: Chris Wright <chr...@redhat.com>
Signed-off-by: Alex Williamson <alex.william...@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>
diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index e254203..2b963b5 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/header.h>
/* From linux/ioport.h */
@@ -649,14 +650,28 @@ 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;
@@ -1467,6 +1482,7 @@ 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 3accdcd..4e7fe87 100644
--- a/hw/device-assignment.h
+++ b/hw/device-assignment.h
@@ -103,6 +103,7 @@ 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;
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