pci passthrough: support "managed" pci device in xend for libvirt usage
PATCH 1/1 pci passthrough: support "managed" pci device in xend for libvirt usage
One of our customers requests parallel pci passthrough functionality between xen (xend and libxl) and kvm, including support managed host pci devices. A "managed" pci device will be made assignable before vm start and reattach to its original dirver after vm shut off.
Currently, libvirt supports "managed=yes/no" options in pci device definition. Qemu driver already supports managed pci devices, libxl driver will add that support in libvirt source code. For xend driver, since it's stateful, libvirt can't do much things because libvirt doesn't store much informtion and most work is done by calling xend directly. Even "managed" option won't be stored if xend doesn't support it. For that reason, this patch series tries to add code in xend toolstack to support managed pci devices first, then libvirt can call xend operations directly to support "managed" host pci devices.
Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']
Please share your comments. Thanks!
PATCH 1/1 pci passtrough: add xm pci-assignable-add/remove commands
Add two commands to xm, make xend toolstack parallel to xl toolstack. Functions can be used in managed pci devices handling.
tools/python/xen/util/pci.py +111 -0
@@ -20,6 +20,7 @@ from xen.xend import sxp from xen.xend.XendConstants import AUTO_PHP_SLOT from xen.xend.XendSXPDev import dev_dict_to_sxp from xen.xend.XendLogging import log +from xen.xend.xenstore.xstransact import xstransact # for 2.3 compatibility try:
@@ -27,9 +28,11 @@ try: except NameError: from sets import Set as set +XS_PCIBACK_PATH = '/xm/pciback' PROC_PCI_PATH = '/proc/bus/pci/devices' PROC_PCI_NUM_RESOURCES = 7 +SYSFS_PCI_DRVS_PATH = 'bus/pci/drivers' SYSFS_PCI_DEVS_PATH = '/bus/pci/devices' SYSFS_PCI_DEV_RESOURCE_PATH = '/resource' SYSFS_PCI_DEV_CONFIG_PATH = '/config'
@@ -427,6 +430,9 @@ def __pci_dict_to_fmt_str(fmt, dev): def pci_dict_to_bdf_str(dev): return __pci_dict_to_fmt_str('%04x:%02x:%02x.%01x', dev) +def pci_dict_to_xs_bdf_str(dev): + return __pci_dict_to_fmt_str('%04x-%02x-%02x-%01x', dev) + def pci_dict_to_xc_str(dev): return __pci_dict_to_fmt_str('0x%x, 0x%x, 0x%x, 0x%x', dev)
@@ -560,6 +566,111 @@ def find_all_assignable_devices(): dev_list = dev_list + [dev] return dev_list +def pci_assignable_add(dev, rebind): + '''detach pci device from driver that we need to unbind from and rebind + to pciback driver, then it can be assigned to guest. + ''' + sysfs_mnt = find_sysfs_mnt() + pcidev_path = sysfs_mnt + SYSFS_PCI_DEVS_PATH + pciback_path = sysfs_mnt + SYSFS_PCIBACK_PATH + + # See if the device exists + pci_bdf = pci_dict_to_bdf_str(dev) + path = pcidev_path + '/' + pci_bdf + if not os.path.exists(path): + log.debug("Pci device %s doesn't exist" % pci_bdf) + return -1 + + # Check to see if it's already assigned to pciback + path = pciback_path + '/' + pci_bdf + if os.path.exists(path): + log.debug("Pci device %s is already assigned to pciback" % pci_bdf) + return 0 + + # Check to see if there's already a driver that we need to unbind from + path = pcidev_path + '/' + pci_bdf + '/driver' + drv_path = None + if os.path.exists(path): + drv_path = os.path.realpath(path) + cmd = 'echo %s > %s/unbind' % (pci_bdf, drv_path) + if os.system(cmd): + log.debug("Couldn't unbind device") + return -1; + + # Store Store driver_path for rebinding to dom0 + if rebind: + if drv_path is not None: + xs_pci_bdf = pci_dict_to_xs_bdf_str(dev) + path = XS_PCIBACK_PATH + '/' + xs_pci_bdf + xstransact.Mkdir(path) + xstransact.Write(path, 'driver_path', drv_path) + else: + log.debug("Not bound to a driver, will not be rebound") + + # Bind to pciback + # Scan through /sys/.../pciback/slots looking for pcidev's BDF + slots = os.popen('cat %s/slots' % pciback_path).read() + if re.search(pci_bdf, slots) is None: + # write bdf to new_slot + cmd = 'echo %s > %s/new_slot' % (pci_bdf, pciback_path) + if os.system(cmd): + log.debug("Couldn't add device to pciback new_slot") + return -1 + + # Bind to pciback + cmd = 'echo %s > %s/bind' % (pci_bdf, pciback_path) + if os.system(cmd): + log.debug("Couldn't bind device to pciback") + return -1 + + return 0 + +def pci_assignable_remove(dev, rebind): + '''unbind pci device from pciback, and rebind to host pci driver where it + was detached from in pci-assignable-add. + ''' + sysfs_mnt = find_sysfs_mnt() + pcidrv_path = sysfs_mnt + SYSFS_PCI_DRVS_PATH + pciback_path = sysfs_mnt + SYSFS_PCIBACK_PATH + pci_bdf = pci_dict_to_bdf_str(dev) + + # Unbind from pciback + path = pciback_path + '/' + pci_bdf + if os.path.exists(path): + # unbind + cmd = 'echo %s > %s/unbind' % (pci_bdf, pciback_path) + if os.system(cmd): + log.debug("Couldn't unbind device to pciback") + return -1 + + # remove slots if necessary + slots = os.popen('cat %s/slots' % pciback_path).read() + if re.search(pci_bdf, slots): + # write bdf to remove_slot + cmd = 'echo %s > %s/remove_slot' % (pci_bdf, pciback_path) + if os.system(cmd): + log.debug("Couldn't remove pciback slot") + return -1 + else: + log.debug("Not bound to pciback") + + # Rebind if necessary + xs_pci_bdf = pci_dict_to_xs_bdf_str(dev) + path = XS_PCIBACK_PATH + '/' + xs_pci_bdf + drv_path = xstransact.Read(path, 'driver_path') + if drv_path: + if rebind: + cmd = 'echo %s > %s/bind' % (pci_bdf, drv_path) + if os.system(cmd): + log.debug("Couldn't rebind to driver %s" % drv_path) + return -1 + xstransact.Remove(path) + else: + if rebind: + log.debug("Counldn't find path for original driver.Not rebinding") + + return 0 + def transform_list(target, src): ''' src: its element is pci string (Format: xxxx:xx:xx.x). target: its element is pci string, or a list of pci string.
tools/python/xen/xm/main.py +23 -0
@@ -211,6 +211,10 @@ SUBCOMMAND_HELP = { 'pci-list' : ('<Domain>', 'List pass-through pci devices for a domain.'), 'pci-list-assignable-devices' : ('', 'List all the assignable pci devices'), + 'pci-assignable-add' : ('<domain:bus:slot.func>', + 'Add a pci device to assignable list.'), + 'pci-assignable-remove' : ('<domain:bus:slot.func>', + 'Remove pci device from assignable list.'), 'scsi-attach' : ('<Domain> <PhysDevice> <VirtDevice> [BackDomain]', 'Attach a new SCSI device.'), 'scsi-detach' : ('<Domain> <VirtDevice>',
@@ -472,6 +476,8 @@ device_commands = [ "pci-detach", "pci-list", "pci-list-assignable-devices", + "pci-assignable-add", + "pci-assignable-remove", "scsi-attach", "scsi-detach", "scsi-list",
@@ -2488,6 +2494,21 @@ def xm_pci_list_assignable_devices(args) pci = parse_pci_info(x) print fmt_str % pci +def xm_pci_assignable_add(args): + xenapi_unsupported() + arg_check(args, "pci-assignable-add", 1) + + pci_dev_str = args[0] + pci_dev = parse_pci_name(pci_dev_str) + pci_assignable_add(pci_dev, 1) + +def xm_pci_assignable_remove(args): + xenapi_unsupported() + arg_check(args, "pci-assignable-remove", 1) + + pci_dev_str = args[0] + pci_dev = parse_pci_name(pci_dev_str) + pci_assignable_remove(pci_dev, 1) def vscsi_sort(devs): def sort_hctl(ds, l):
@@ -3824,6 +3845,8 @@ commands = { "pci-detach": xm_pci_detach, "pci-list": xm_pci_list, "pci-list-assignable-devices": xm_pci_list_assignable_devices, + "pci-assignable-add": xm_pci_assignable_add, + "pci-assignable-remove": xm_pci_assignable_remove, # vscsi "scsi-attach": xm_scsi_attach, "scsi-detach": xm_scsi_detach,
PATCH 1/1 pci passthrough: handle managed pci devices
In reply to [email protected]Handle managed pci devices for libvirt usage. If a pci device is set "managed=1", it will be made assignable (unbound from original driver and bind to pcistub driver) before vm start and reattach to original driver after vm shut off.
tools/python/xen/util/pci.py +1 -1
@@ -164,7 +164,7 @@ def PCI_BDF(domain, bus, slot, func): def check_pci_opts(opts): def f((k, v)): - if k not in ['msitranslate', 'power_mgmt'] or \ + if k not in ['msitranslate', 'power_mgmt', 'managed'] or \ not v.lower() in ['0', '1', 'yes', 'no']: raise PciDeviceParseError('Invalid pci option %s=%s: ' % (k, v))
tools/python/xen/xend/XendDomainInfo.py +22 -1
@@ -303,7 +303,8 @@ def dom_get(dom): return None from xen.xend.server.pciif import parse_pci_name, PciDevice,\ - get_assigned_pci_devices, get_all_assigned_pci_devices + get_assigned_pci_devices, get_all_assigned_pci_devices,\ + prepare_host_pci_devices, reattach_host_pci_devices def do_FLR(domid, is_hvm):
@@ -317,6 +318,20 @@ def do_FLR(domid, is_hvm): "parse it's resources - "+str(e)) dev.do_FLR(is_hvm, xoptions.get_pci_dev_assign_strict_check()) +def prepare_domain_pci_devices(domconfig): + ordered_refs = domconfig.ordered_device_refs() + for dev_uuid in ordered_refs: + devclass, devconfig = domconfig['devices'][dev_uuid] + if devclass == 'pci': + prepare_host_pci_devices(devconfig) + +def reattach_domain_pci_devices(domconfig): + ordered_refs = domconfig.ordered_device_refs() + for dev_uuid in ordered_refs: + devclass, devconfig = domconfig['devices'][dev_uuid] + if devclass == 'pci': + reattach_host_pci_devices(devconfig) + class XendDomainInfo: """An object represents a domain.
@@ -470,6 +485,7 @@ class XendDomainInfo: if self._stateGet() in (XEN_API_VM_POWER_STATE_HALTED, XEN_API_VM_POWER_STATE_SUSPENDED, XEN_API_VM_POWER_STATE_CRASHED): try: + prepare_domain_pci_devices(self.info); XendTask.log_progress(0, 30, self._constructDomain) XendTask.log_progress(31, 60, self._initDomain)
@@ -496,6 +512,7 @@ class XendDomainInfo: state = self._stateGet() if state in (DOM_STATE_SUSPENDED, DOM_STATE_HALTED): try: + prepare_domain_pci_devices(self.info) self._constructDomain() try:
@@ -838,6 +855,9 @@ class XendDomainInfo: log.debug("XendDomainInfo.device_create: %s" % scrub_password(dev_config)) dev_type = sxp.name(dev_config) + if dev_type == 'pci': + prepare_host_pci_devices(devconfig) + if dev_type == 'vif': for x in dev_config: if x != 'vif' and x[0] == 'mac':
@@ -3099,6 +3119,7 @@ class XendDomainInfo: log.debug("%s KiB need to add to Memory pool" %self.alloc_mem) MemoryPool.instance().increase_memory(self.alloc_mem) + reattach_domain_pci_devices(self.info) self._cleanup_phantom_devs(paths) self._cleanupVm()
tools/python/xen/xend/server/pciif.py +26 -0
@@ -86,6 +86,32 @@ def get_all_assigned_pci_devices(domid = pci_str_list = pci_str_list + get_assigned_pci_devices(int(d)) return pci_str_list +def prepare_host_pci_devices(devconfig): + pci_dev_list = devconfig.get('devs', []) + for pci_dev in pci_dev_list: + managed = 0 + pci_opts_config = pci_dev.get('opts', []) + for opt in pci_opts_config: + if opt[0] == 'managed': + managed = opt[1] + if managed: + if pci_assignable_add(pci_dev, 1) != 0: + raise VmError('pci_assignable_add failed') + return + +def reattach_host_pci_devices(devconfig): + pci_dev_list = devconfig.get('devs', []) + for pci_dev in pci_dev_list: + managed = 0 + pci_opts_config = pci_dev['opts'] + for opt in pci_opts_config: + if opt[0] == 'managed': + managed = opt[1] + if managed: + if pci_assignable_remove(pci_dev, 1) != 0: + raise VmError('pci_assignable_remove failed') + return + class PciController(DevController): def __init__(self, vm):
tools/python/xen/xm/create.py +4 -2
@@ -332,7 +332,7 @@ gopts.var('disk', val='phy:DEV,VDEV,MODE backend driver domain to use for the disk. The option may be repeated to add more than one disk.""") -gopts.var('pci', val='BUS:DEV.FUNC[@VSLOT][,msitranslate=0|1][,power_mgmt=0|1]', +gopts.var('pci', val='BUS:DEV.FUNC[@VSLOT][,msitranslate=0|1][,power_mgmt=0|1][,managed=0|1]', fn=append_value, default=[], use="""Add a PCI device to a domain, using given params (in hex). For example 'pci=c0:02.1'.
@@ -343,7 +343,9 @@ gopts.var('pci', val='BUS:DEV.FUNC[@VSLO translated from physical MSI, HVM only. Default is 1. The option may be repeated to add more than one pci device. If power_mgmt is set, the guest OS will be able to program the power - states D0-D3hot of the device, HVM only. Default=0.""") + states D0-D3hot of the device, HVM only. Default=0. + If managed is set, pci device will be prepared and released when VM + is started or shut off""") gopts.var('vscsi', val='PDEV,VDEV[,DOM]', fn=append_value, default=[],
Quoted 22 lines · On Thu, Jan 17, 2013 at 5:29 AM, <[email protected]> wrote:
One of our customers requests parallel pci passthrough functionality between xen
(xend and libxl) and kvm, including support managed host pci devices. A "managed" pci device will be made assignable before vm start and reattach to
its original dirver after vm shut off.Currently, libvirt supports "managed=yes/no" options in pci device definition.
Qemu driver already supports managed pci devices, libxl driver will add that
support in libvirt source code. For xend driver, since it's stateful, libvirt
can't do much things because libvirt doesn't store much informtion and most work is done by calling xend directly. Even "managed" option won't be stored if
xend doesn't support it. For that reason, this patch series tries to add code in
xend toolstack to support managed pci devices first, then libvirt can call xend
operations directly to support "managed" host pci devices.
Quoted 5 lines
Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']Please share your comments. Thanks!
The first question (before I look at the code closely) is whether we want to accept new features into xend. It's not being actively maintained, and we would like to get rid of it at some point.
Given that you seem primarily to be using libvirt, after the 4.3 release, will there be a strong reason to use xend, instead of just using libxl?
Note I'm not rejecting it outright; I just think a case needs to be made. :-)
-George
_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xen.org/xen-devel
Quoted 33 lines · George Dunlap
On Thu, Jan 17, 2013 at 5:29 AM, <[email protected]
<mailto:[email protected]>> wrote:One of our customers requests parallel pci passthrough functionality between xen
(xend and libxl) and kvm, including support managed host pci devices. A
"managed" pci device will be made assignable before vm start and reattach to
its original dirver after vm shut off.Currently, libvirt supports "managed=yes/no" options in pci device definition.
Qemu driver already supports managed pci devices, libxl driver will add that
support in libvirt source code. For xend driver, since it's stateful, libvirt
can't do much things because libvirt doesn't store much informtion and most
work is done by calling xend directly. Even "managed" option won't be stored if
xend doesn't support it. For that reason, this patch series tries to add code in
xend toolstack to support managed pci devices first, then libvirt can call xend
operations directly to support "managed" host pci devices.Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']Please share your comments. Thanks!
Quoted 7 lines
The first question (before I look at the code closely) is whether we want to accept new features into xend. It's not being actively maintained, and we would like to get rid of it at some point.
Given that you seem primarily to be using libvirt, after the 4.3 release, will there be a strong reason to use xend, instead of just using libxl?
Our SLE11 enterprise product uses the legacy toolstack and I doubt we will change that until SLE12. We need to give users time to migrate from the old toolstack as well.
Chunyan first added this functionality to the libvirt libxl driver [1], since it is preferred going forward. Unfortunately we need to provide the same functionality in the old toolstack. We can carry this patch in our packages if needed, but upstream backports are certainly preferred over local patches.
Quoted 2 lines
Note I'm not rejecting it outright; I just think a case needs to be made. :-)
Ok, I've made an attempt :).
Regards,
Jim
[1] https://www.redhat.com/archives/libvir-list/2013-January/msg00689.html
Quoted 46 lines · Jim Fehlig
Quoted 33 lines · George Dunlap
On Thu, Jan 17, 2013 at 5:29 AM, <[email protected]
<mailto:[email protected]>> wrote:One of our customers requests parallel pci passthrough functionality between xen
(xend and libxl) and kvm, including support managed host pci devices. A
"managed" pci device will be made assignable before vm start and reattach to
its original dirver after vm shut off.Currently, libvirt supports "managed=yes/no" options in pci device definition.
Qemu driver already supports managed pci devices, libxl driver will add that
support in libvirt source code. For xend driver, since it's stateful, libvirt
can't do much things because libvirt doesn't store much informtion and most
work is done by calling xend directly. Even "managed" option won't be stored if
xend doesn't support it. For that reason, this patch series tries to add code in
xend toolstack to support managed pci devices first, then libvirt can call xend
operations directly to support "managed" host pci devices.Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']Please share your comments. Thanks!
Quoted 7 lines
The first question (before I look at the code closely) is whether we want to accept new features into xend. It's not being actively maintained, and we would like to get rid of it at some point.
Given that you seem primarily to be using libvirt, after the 4.3 release, will there be a strong reason to use xend, instead of just using libxl?
Our SLE11 enterprise product uses the legacy toolstack and I doubt we will change that until SLE12. We need to give users time to migrate from the old toolstack as well.
Quoted 5 lines
Chunyan first added this functionality to the libvirt libxl driver [1], since it is preferred going forward. Unfortunately we need to provide the same functionality in the old toolstack. We can carry this patch in our packages if needed, but upstream backports are certainly preferred over local patches.
So I'm hearing that one reason you want it upstream is because you prefer to have a backport, rather than just having a stand-alone patch in your queue.
That's a very good general policy, but it's not necessarily a reason why xen.org should take the patch. The main reason we would take the patch would be, "SuSE will use it in 4.3".
But it's not clear that's the case -- are you planning on pulling Xen 4.3 into SLE 11? Do you think that you'll need xend in SLE12 "to give users time to migrate"?
If we really are going to get rid of xend, there must be a point where users are "pushed", by lack of features (or lack of existence) onto the new toolstack. Feature parity in new releases is only going to delay the inevitable.
We've tried to make that step as simple as possible, by making xl compatible with xend, and by making sure key functionality has been carried over. If there are still things that will make that transition hard, maybe you could point those out and we can see if we can address them?
Overall it seems like if we stick with straight principles, we shouldn't take the patch.
But I'm not adamant -- I'd be interested in hearing other opinions.
The other option, of course, would be for someone / some organization to commit to being the xend maintainer going forward -- which would probably involve committing to porting new libxl features over to xend.
I don't think that's recommended, but everyone can spend their own
money / engineering hours how they like. :-)
-George
Quoted 57 lines · George Dunlap
Quoted 46 lines · Jim Fehlig
Quoted 33 lines · George Dunlap
On Thu, Jan 17, 2013 at 5:29 AM, <[email protected]
<mailto:[email protected]>> wrote:One of our customers requests parallel pci passthrough functionality between xen
(xend and libxl) and kvm, including support managed host pci devices. A
"managed" pci device will be made assignable before vm start and reattach to
its original dirver after vm shut off.Currently, libvirt supports "managed=yes/no" options in pci device definition.
Qemu driver already supports managed pci devices, libxl driver will add that
support in libvirt source code. For xend driver, since it's stateful, libvirt
can't do much things because libvirt doesn't store much informtion and most
work is done by calling xend directly. Even "managed" option won't be stored if
xend doesn't support it. For that reason, this patch series tries to add code in
xend toolstack to support managed pci devices first, then libvirt can call xend
operations directly to support "managed" host pci devices.Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']Please share your comments. Thanks!
Quoted 7 lines
The first question (before I look at the code closely) is whether we want to accept new features into xend. It's not being actively maintained, and we would like to get rid of it at some point.
Given that you seem primarily to be using libvirt, after the 4.3 release, will there be a strong reason to use xend, instead of just using libxl?
Our SLE11 enterprise product uses the legacy toolstack and I doubt we will change that until SLE12. We need to give users time to migrate from the old toolstack as well.
Quoted 5 lines
Chunyan first added this functionality to the libvirt libxl driver [1], since it is preferred going forward. Unfortunately we need to provide the same functionality in the old toolstack. We can carry this patch in our packages if needed, but upstream backports are certainly preferred over local patches.
So I'm hearing that one reason you want it upstream is because you prefer to have a backport, rather than just having a stand-alone patch in your queue.
Quoted 6 lines
That's a very good general policy, but it's not necessarily a reason why xen.org should take the patch. The main reason we would take the patch would be, "SuSE will use it in 4.3".
But it's not clear that's the case -- are you planning on pulling Xen 4.3 into SLE 11?
Probably not.
Quoted 2 lines
Do you think that you'll need xend in SLE12 "to give users time to
migrate"?
No.
Quoted 10 lines
If we really are going to get rid of xend, there must be a point where users are "pushed", by lack of features (or lack of existence) onto the new toolstack. Feature parity in new releases is only going to delay the inevitable.
We've tried to make that step as simple as possible, by making xl compatible with xend, and by making sure key functionality has been carried over. If there are still things that will make that transition hard, maybe you could point those out and we can see if we can address them?
I'm not aware of anything. Users simply need time to migrate their existing tools, scripts, etc. and we didn't want to force that on them in a service pack. A new version of SLE is a different matter.
Quoted 10 lines
Overall it seems like if we stick with straight principles, we shouldn't take the patch.
But I'm not adamant -- I'd be interested in hearing other opinions.
The other option, of course, would be for someone / some organization to commit to being the xend maintainer going forward -- which would probably involve committing to porting new libxl features over to xend. I don't think that's recommended, but everyone can spend their own money / engineering hours how they like. :-)
I wouldn't recommend that either, and designating someone as the xend maintainer is inhumane :).
Jim
Quoted 60 lines · Jim Fehlig
Quoted 59 lines · George Dunlap
Quoted 45 lines · Jim Fehlig
Quoted 33 lines · George Dunlap
On Thu, Jan 17, 2013 at 5:29 AM, <[email protected]
<mailto:[email protected]>> wrote:One of our customers requests parallel pci passthrough functionality between xen
(xend and libxl) and kvm, including support managed host pci devices. A
"managed" pci device will be made assignable before vm start and reattach to
its original dirver after vm shut off.Currently, libvirt supports "managed=yes/no" options in pci device definition.
Qemu driver already supports managed pci devices, libxl driver will add that
support in libvirt source code. For xend driver, since it's stateful, libvirt
can't do much things because libvirt doesn't store much informtion and most
work is done by calling xend directly. Even "managed" option won't be stored if
xend doesn't support it. For that reason, this patch series tries to add code in
xend toolstack to support managed pci devices first, then libvirt can call xend
operations directly to support "managed" host pci devices.Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']Please share your comments. Thanks!
Quoted 7 lines
The first question (before I look at the code closely) is whether we want to accept new features into xend. It's not being actively maintained, and we would like to get rid of it at some point.
Given that you seem primarily to be using libvirt, after the 4.3 release, will there be a strong reason to use xend, instead of just using libxl?
Our SLE11 enterprise product uses the legacy toolstack and I doubt we will change that until SLE12. We need to give users time to migrate from the old toolstack as well.
Quoted 5 lines
Chunyan first added this functionality to the libvirt libxl driver [1], since it is preferred going forward. Unfortunately we need to provide the same functionality in the old toolstack. We can carry this patch in our packages if needed, but upstream backports are certainly preferred over local patches.
So I'm hearing that one reason you want it upstream is because you prefer to have a backport, rather than just having a stand-alone patch in your queue.
That's a very good general policy, but it's not necessarily a reason why xen.org should take the patch. The main reason we would take the patch would be, "SuSE will use it in 4.3".
Quoted 7 lines
Quoted 2 lines
But it's not clear that's the case -- are you planning on pulling Xen 4.3 into SLE 11?
Probably not.
Quoted 2 lines
Do you think that you'll need xend in SLE12 "to give users time to
migrate"?No.
OK, so it sounds like you're not going to need this in 4.3, so we can leave it out of xen.org.
Quoted 6 lines
Quoted 6 lines
If we really are going to get rid of xend, there must be a point where users are "pushed", by lack of features (or lack of existence) onto the new toolstack. Feature parity in new releases is only going to delay the inevitable.
Quoted 8 lines
Quoted 5 lines
We've tried to make that step as simple as possible, by making xl compatible with xend, and by making sure key functionality has been carried over. If there are still things that will make that transition hard, maybe you could point those out and we can see if we can address them?
I'm not aware of anything. Users simply need time to migrate their existing tools, scripts, etc. and we didn't want to force that on them in a service pack. A new version of SLE is a different matter.
Sure, and as a distro it totally makes sense to carry it as a patch until then.
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Overall it seems like if we stick with straight principles, we shouldn't take the patch.
But I'm not adamant -- I'd be interested in hearing other opinions.
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The other option, of course, would be for someone / some organization to commit to being the xend maintainer going forward -- which would probably involve committing to porting new libxl features over to xend. I don't think that's recommended, but everyone can spend their own money / engineering hours how they like. :-)
I wouldn't recommend that either, and designating someone as the xend maintainer is inhumane :).
Haha -- I'm glad we agree on that. :-)
-George
Quoted 30 lines · George Dunlap
Quoted 22 lines · On Thu, Jan 17, 2013 at 5:29 AM, <[email protected]> wrote:
One of our customers requests parallel pci passthrough functionality between xen
(xend and libxl) and kvm, including support managed host pci devices. A "managed" pci device will be made assignable before vm start and reattach to
its original dirver after vm shut off.Currently, libvirt supports "managed=yes/no" options in pci device definition.
Qemu driver already supports managed pci devices, libxl driver will add that
support in libvirt source code. For xend driver, since it's stateful, libvirt
can't do much things because libvirt doesn't store much informtion and most work is done by calling xend directly. Even "managed" option won't be stored if
xend doesn't support it. For that reason, this patch series tries to add code in
xend toolstack to support managed pci devices first, then libvirt can call xend
operations directly to support "managed" host pci devices.Quoted 5 lines
Syntax for managed pci device could be:
pci=['0000:00:1a.0,managed=1']Please share your comments. Thanks!
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The first question (before I look at the code closely) is whether we want to accept new features into xend. It's not being actively maintained, and we would like to get rid of it at some point.
Given that you seem primarily to be using libvirt, after the 4.3 release, will there be a strong reason to use xend, instead of just using libxl?
Note I'm not rejecting it outright; I just think a case needs to be made.
I am actually in favour of adding things in both. There are multiple distros that are still using Xen 4.1 and some of them have a long life-cycle. Adding in features that are also reflected in 'xl' looks to be the doing the right thing for the customers and with the future in mind.
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:-)
-George
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Quoted 3 lines · Konrad Rzeszutek Wilk
I am actually in favour of adding things in both. There are multiple distros that are still using Xen 4.1 and some of them have a long life-cycle.
Even if we were to take xend patches in unstable I wouldn't expect them to be backported to 4.1 at this point.
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Adding in features that are also reflected in 'xl' looks to be the
doing the right thing for the customers and with the future in mind.
In order for us to start habitually taking patches which implement new features in xend again someone needs to step up and take responsibility for it. i.e. reviewing the patches and fixing the regressions they introduce. Probably they should add themselves to MAINTAINERS.
I've no objections to someone who wants to become the xend maintainer stepping up and doing the job but just slapping patches in isn't the answer.
Personally I think that having made the decision to deprecate xend we should just let it die and not prolong the pain.
Ian.