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virpcimock: Create driver_override file in device dirs

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Newer kernels (v3.16-rc1~29^2~6^4) have 'driver_override' file
which simplifies way of binding a PCI device to desired driver.
Libvirt has support for this for some time too (v2.3.0-rc1~236),
but not our virpcimock. So far we did not care because our code
is designed to deal with this situation. Except for one.
hypothetical case: binding a device to the vfio-pci driver can be
successful only via driver_override. Any attempt to bind a PCI
device to vfio-pci driver using old method (new_id + unbind +
bind) will fail because of b803b29c1a. While on vanilla kernel
I'm able to use the old method successfully, it's failing on RHEL
kernels (not sure why).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
This commit is contained in:
Michal Privoznik 2019-06-17 16:42:23 +02:00
parent 915d2281f3
commit 84f9358b18
1 changed files with 46 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
tests/virpcimock.c
View File

@ -88,6 +88,11 @@ char *fakesysfspcidir;
* Probe for a driver that handles the specified device.
* Data in format "DDDD:BB:DD.F" (Domain:Bus:Device.Function).
*
* /sys/bus/pci/devices/<device>/driver_override
* Name of a driver that overrides preferred driver can be written
* here. The device will be attached to it on drivers_probe event.
* Writing an empty string (or "\n") clears the override.
*
* As a little hack, we are not mocking write to these files, but close()
* instead. The advantage is we don't need any self growing array to hold the
* partial writes and construct them back. We can let all the writes finish,
@ -148,6 +153,7 @@ static struct pciDevice *pci_device_find_by_content(const char *path);
static void pci_driver_new(const char *name, int fail, ...);
static struct pciDriver *pci_driver_find_by_dev(struct pciDevice *dev);
static struct pciDriver *pci_driver_find_by_path(const char *path);
static struct pciDriver *pci_driver_find_by_driver_override(struct pciDevice *dev);
static int pci_driver_bind(struct pciDriver *driver, struct pciDevice *dev);
static int pci_driver_unbind(struct pciDriver *driver, struct pciDevice *dev);
static int pci_driver_handle_change(int fd, const char *path);
@ -203,7 +209,8 @@ make_symlink(const char *path,
static int
pci_read_file(const char *path,
char *buf,
size_t buf_size)
size_t buf_size,
bool truncate)
{
int ret = -1;
int fd = -1;
@ -225,7 +232,8 @@ pci_read_file(const char *path,
goto cleanup;
}
if (ftruncate(fd, 0) < 0)
if (truncate &&
ftruncate(fd, 0) < 0)
goto cleanup;
ret = 0;
@ -399,6 +407,8 @@ pci_device_new_from_stub(const struct pciDevice *data)
ABORT("@tmp overflow");
make_file(devpath, "class", tmp, -1);
make_file(devpath, "driver_override", NULL, -1);
if (snprintf(tmp, sizeof(tmp),
"%s/../../../kernel/iommu_groups/%d",
devpath, dev->iommuGroup) < 0) {
@ -442,7 +452,7 @@ pci_device_find_by_content(const char *path)
{
char tmp[32];
if (pci_read_file(path, tmp, sizeof(tmp)) < 0)
if (pci_read_file(path, tmp, sizeof(tmp), true) < 0)
return NULL;
return pci_device_find_by_id(tmp);
@ -451,7 +461,10 @@ pci_device_find_by_content(const char *path)
static int
pci_device_autobind(struct pciDevice *dev)
{
struct pciDriver *driver = pci_driver_find_by_dev(dev);
struct pciDriver *driver = pci_driver_find_by_driver_override(dev);
if (!driver)
driver = pci_driver_find_by_dev(dev);
if (!driver) {
/* No driver found. Nothing to do */
@ -545,6 +558,31 @@ pci_driver_find_by_path(const char *path)
return NULL;
}
static struct pciDriver *
pci_driver_find_by_driver_override(struct pciDevice *dev)
{
VIR_AUTOFREE(char *) path = NULL;
char tmp[32];
size_t i;
if (virAsprintfQuiet(&path,
SYSFS_PCI_PREFIX "devices/%s/driver_override",
dev->id) < 0)
return NULL;
if (pci_read_file(path, tmp, sizeof(tmp), false) < 0)
return NULL;
for (i = 0; i < nPCIDrivers; i++) {
struct pciDriver *driver = pciDrivers[i];
if (STREQ(tmp, driver->name))
return driver;
}
return NULL;
}
static int
pci_driver_bind(struct pciDriver *driver,
struct pciDevice *dev)
@ -658,6 +696,8 @@ pci_driver_handle_change(int fd ATTRIBUTE_UNUSED, const char *path)
ret = pci_driver_handle_remove_id(path);
else if (STREQ(file, "drivers_probe"))
ret = pci_driver_handle_drivers_probe(path);
else if (STREQ(file, "driver_override"))
ret = 0; /* nada */
else
ABORT("Not handled write to: %s", path);
return ret;
@ -712,7 +752,7 @@ pci_driver_handle_new_id(const char *path)
goto cleanup;
}
if (pci_read_file(path, buf, sizeof(buf)) < 0)
if (pci_read_file(path, buf, sizeof(buf), true) < 0)
goto cleanup;
if (sscanf(buf, "%x %x", &vendor, &device) < 2) {
@ -767,7 +807,7 @@ pci_driver_handle_remove_id(const char *path)
goto cleanup;
}
if (pci_read_file(path, buf, sizeof(buf)) < 0)
if (pci_read_file(path, buf, sizeof(buf), true) < 0)
goto cleanup;
if (sscanf(buf, "%x %x", &vendor, &device) < 2) {