In the past, the only allowable values for the "driver" field of
virNodeDeviceDetachFlags() were "kvm" or "vfio" for the QEMU driver,
and "xen" for the libxl driver. Then "kvm" was deprecated and removed,
so the driver name became essentially irrelevant (because it is always
called via a particular hypervisor driver, and so the "xen" or "vfio"
can be (and almost always is) implied.
With the advent of VFIO variant drivers, the ability to explicitly
specify a driver name once again becomes useful - it can be used to
name the exact VFIO driver that we want bound to the device in place
of vfio-pci, so this patch allows those other names to be passed down
the call chain, where the code in virpci.c can make use of them.
The names "vfio", "kvm", and "xen" retain their special meaning, though:
1) because there may be some application or configuration that still
calls virNodeDeviceDetachFlags() with driverName="vfio", this
single value is substituted with the synonym of NULL, which means
"bind the default driver for this device and hypervisor". This
will currently result in the vfio-pci driver being bound to the
device.
2) in the case of the libxl driver, "xen" means to use the standard
driver used in the case of Xen ("pciback").
3) "kvm" as a driver name always results in an error, as legacy KVM
device assignment was removed from the kernel around 10 years ago.
Signed-off-by: Laine Stump <laine@redhat.com>
---
src/hypervisor/domain_driver.c | 9 ++++-----
src/hypervisor/domain_driver.h | 2 ++
src/libxl/libxl_driver.c | 3 ++-
src/qemu/qemu_driver.c | 33 +++++++++++++++++++--------------
4 files changed, 27 insertions(+), 20 deletions(-)
diff --git a/src/hypervisor/domain_driver.c b/src/hypervisor/domain_driver.c
index a70f75f3ae..429784292a 100644
--- a/src/hypervisor/domain_driver.c
+++ b/src/hypervisor/domain_driver.c
@@ -462,6 +462,7 @@ virDomainDriverNodeDeviceReAttach(virNodeDevicePtr dev,
int
virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
virHostdevManager *hostdevMgr,
+ virPCIStubDriver driverType,
const char *driverName)
{
g_autoptr(virPCIDevice) pci = NULL;
@@ -471,7 +472,7 @@ virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
g_autoptr(virConnect) nodeconn = NULL;
g_autoptr(virNodeDevice) nodedev = NULL;
- if (!driverName)
+ if (driverType == VIR_PCI_STUB_DRIVER_NONE)
return -1;
if (!(nodeconn = virGetConnectNodeDev()))
@@ -504,10 +505,8 @@ virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
if (!pci)
return -1;
- if (STREQ(driverName, "vfio"))
- virPCIDeviceSetStubDriverType(pci, VIR_PCI_STUB_DRIVER_VFIO);
- else if (STREQ(driverName, "xen"))
- virPCIDeviceSetStubDriverType(pci, VIR_PCI_STUB_DRIVER_XEN);
+ virPCIDeviceSetStubDriverType(pci, driverType);
+ virPCIDeviceSetStubDriverName(pci, driverName);
return virHostdevPCINodeDeviceDetach(hostdevMgr, pci);
}
diff --git a/src/hypervisor/domain_driver.h b/src/hypervisor/domain_driver.h
index 4241c86932..9942f58fda 100644
--- a/src/hypervisor/domain_driver.h
+++ b/src/hypervisor/domain_driver.h
@@ -22,6 +22,7 @@
#include "node_device_conf.h"
#include "virhostdev.h"
+#include "virpci.h"
char *
virDomainDriverGenerateRootHash(const char *drivername,
@@ -58,6 +59,7 @@ int virDomainDriverNodeDeviceReAttach(virNodeDevicePtr dev,
int virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
virHostdevManager *hostdevMgr,
+ virPCIStubDriver driverType,
const char *driverName);
int virDomainDriverAddIOThreadCheck(virDomainDef *def,
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 3d10f45850..079922dd32 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -5876,7 +5876,8 @@ libxlNodeDeviceDetachFlags(virNodeDevicePtr dev,
/* virNodeDeviceDetachFlagsEnsureACL() is being called by
* virDomainDriverNodeDeviceDetachFlags() */
- return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr, driverName);
+ return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr,
+ VIR_PCI_STUB_DRIVER_XEN, NULL);
}
static int
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index f8039160f4..f676744e9e 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -70,7 +70,6 @@
#include "domain_driver.h"
#include "domain_postparse.h"
#include "domain_validate.h"
-#include "virpci.h"
#include "virpidfile.h"
#include "virprocess.h"
#include "libvirt_internal.h"
@@ -11400,24 +11399,28 @@ qemuNodeDeviceDetachFlags(virNodeDevicePtr dev,
virCheckFlags(0, -1);
- if (!driverName)
- driverName = "vfio";
-
- /* Only the 'vfio' driver is supported and a special error message for
- * the previously supported 'kvm' driver is provided below. */
- if (STRNEQ(driverName, "vfio") && STRNEQ(driverName, "kvm")) {
- virReportError(VIR_ERR_INVALID_ARG,
- _("unknown driver name '%1$s'"), driverName);
- return -1;
- }
+ /* For historical reasons, if driverName is "vfio", that is the
+ * same as NULL, i.e. the default vfio driver for this device
+ */
+ if (STREQ_NULLABLE(driverName, "vfio"))
+ driverName = NULL;
- if (STREQ(driverName, "kvm")) {
+ /* the "kvm" driver name was used a very long time ago to force
+ * "legacy KVM device assignment", which hasn't been supported in
+ * over 10 years.
+ */
+ if (STREQ_NULLABLE(driverName, "kvm")) {
virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
- _("KVM device assignment is no longer "
+ _("'legacy KVM' device assignment is no longer "
"supported on this system"));
return -1;
}
+ /* for any other driver, we can't know whether or not it is a VFIO
+ * driver until the device has been bound to it, so we will defer
+ * further validation until then.
+ */
+
if (!qemuHostdevHostSupportsPassthroughVFIO()) {
virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
_("VFIO device assignment is currently not "
@@ -11427,7 +11430,9 @@ qemuNodeDeviceDetachFlags(virNodeDevicePtr dev,
/* virNodeDeviceDetachFlagsEnsureACL() is being called by
* virDomainDriverNodeDeviceDetachFlags() */
- return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr, driverName);
+ return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr,
+ VIR_PCI_STUB_DRIVER_VFIO,
+ driverName);
}
static int
--
2.41.0On 8/21/23 21:32, Laine Stump wrote:
> In the past, the only allowable values for the "driver" field of
> virNodeDeviceDetachFlags() were "kvm" or "vfio" for the QEMU driver,
> and "xen" for the libxl driver. Then "kvm" was deprecated and removed,
> so the driver name became essentially irrelevant (because it is always
> called via a particular hypervisor driver, and so the "xen" or "vfio"
> can be (and almost always is) implied.
>
> With the advent of VFIO variant drivers, the ability to explicitly
> specify a driver name once again becomes useful - it can be used to
> name the exact VFIO driver that we want bound to the device in place
> of vfio-pci, so this patch allows those other names to be passed down
> the call chain, where the code in virpci.c can make use of them.
>
> The names "vfio", "kvm", and "xen" retain their special meaning, though:
>
> 1) because there may be some application or configuration that still
> calls virNodeDeviceDetachFlags() with driverName="vfio", this
> single value is substituted with the synonym of NULL, which means
> "bind the default driver for this device and hypervisor". This
> will currently result in the vfio-pci driver being bound to the
> device.
>
> 2) in the case of the libxl driver, "xen" means to use the standard
> driver used in the case of Xen ("pciback").
>
> 3) "kvm" as a driver name always results in an error, as legacy KVM
> device assignment was removed from the kernel around 10 years ago.
>
> Signed-off-by: Laine Stump <laine@redhat.com>
> ---
> src/hypervisor/domain_driver.c | 9 ++++-----
> src/hypervisor/domain_driver.h | 2 ++
> src/libxl/libxl_driver.c | 3 ++-
> src/qemu/qemu_driver.c | 33 +++++++++++++++++++--------------
> 4 files changed, 27 insertions(+), 20 deletions(-)
>
> diff --git a/src/hypervisor/domain_driver.c b/src/hypervisor/domain_driver.c
> index a70f75f3ae..429784292a 100644
> --- a/src/hypervisor/domain_driver.c
> +++ b/src/hypervisor/domain_driver.c
> @@ -462,6 +462,7 @@ virDomainDriverNodeDeviceReAttach(virNodeDevicePtr dev,
> int
> virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
> virHostdevManager *hostdevMgr,
> + virPCIStubDriver driverType,
> const char *driverName)
> {
> g_autoptr(virPCIDevice) pci = NULL;
> @@ -471,7 +472,7 @@ virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
> g_autoptr(virConnect) nodeconn = NULL;
> g_autoptr(virNodeDevice) nodedev = NULL;
>
> - if (!driverName)
> + if (driverType == VIR_PCI_STUB_DRIVER_NONE)
> return -1;
Even though, we are very unlikely to hit this check, the rest of the
function reports an error on error paths. Please virReportError() here too.
Michal
On 8/23/23 3:52 AM, Michal Prívozník wrote:
> On 8/21/23 21:32, Laine Stump wrote:
>> In the past, the only allowable values for the "driver" field of
>> virNodeDeviceDetachFlags() were "kvm" or "vfio" for the QEMU driver,
>> and "xen" for the libxl driver. Then "kvm" was deprecated and removed,
>> so the driver name became essentially irrelevant (because it is always
>> called via a particular hypervisor driver, and so the "xen" or "vfio"
>> can be (and almost always is) implied.
>>
>> With the advent of VFIO variant drivers, the ability to explicitly
>> specify a driver name once again becomes useful - it can be used to
>> name the exact VFIO driver that we want bound to the device in place
>> of vfio-pci, so this patch allows those other names to be passed down
>> the call chain, where the code in virpci.c can make use of them.
>>
>> The names "vfio", "kvm", and "xen" retain their special meaning, though:
>>
>> 1) because there may be some application or configuration that still
>> calls virNodeDeviceDetachFlags() with driverName="vfio", this
>> single value is substituted with the synonym of NULL, which means
>> "bind the default driver for this device and hypervisor". This
>> will currently result in the vfio-pci driver being bound to the
>> device.
>>
>> 2) in the case of the libxl driver, "xen" means to use the standard
>> driver used in the case of Xen ("pciback").
>>
>> 3) "kvm" as a driver name always results in an error, as legacy KVM
>> device assignment was removed from the kernel around 10 years ago.
>>
>> Signed-off-by: Laine Stump <laine@redhat.com>
>> ---
>> src/hypervisor/domain_driver.c | 9 ++++-----
>> src/hypervisor/domain_driver.h | 2 ++
>> src/libxl/libxl_driver.c | 3 ++-
>> src/qemu/qemu_driver.c | 33 +++++++++++++++++++--------------
>> 4 files changed, 27 insertions(+), 20 deletions(-)
>>
>> diff --git a/src/hypervisor/domain_driver.c b/src/hypervisor/domain_driver.c
>> index a70f75f3ae..429784292a 100644
>> --- a/src/hypervisor/domain_driver.c
>> +++ b/src/hypervisor/domain_driver.c
>> @@ -462,6 +462,7 @@ virDomainDriverNodeDeviceReAttach(virNodeDevicePtr dev,
>> int
>> virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
>> virHostdevManager *hostdevMgr,
>> + virPCIStubDriver driverType,
>> const char *driverName)
>> {
>> g_autoptr(virPCIDevice) pci = NULL;
>> @@ -471,7 +472,7 @@ virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
>> g_autoptr(virConnect) nodeconn = NULL;
>> g_autoptr(virNodeDevice) nodedev = NULL;
>>
>> - if (!driverName)
>> + if (driverType == VIR_PCI_STUB_DRIVER_NONE)
>> return -1;
>
> Even though, we are very unlikely to hit this check, the rest of the
> function reports an error on error paths. Please virReportError() here too.
Nice catch! Although 1) this is pre-existing (added all the way back in
commit 887dd0d33), and 2) with the current code it would be impossible
for this error to occur (since both callers set driverType to something
other than NONE), still there is no point in having the check there if
it's just going to fail silently on that fateful day in the future when
someone modifies the code such that all the callers *don't* set
driverType != NONE.
I'll add an error log before I push.
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