[CentOS-virt] Are xen and centos incompatible?

Mon Jun 16 17:16:57 UTC 2014
Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>

On Sat, Jun 14, 2014 at 09:07:51AM +0200, lee wrote:
> Konrad Rzeszutek Wilk <konrad.wilk at oracle.com> writes:
> 
> >> Hm, xen kinda makes the cpus and their power management invisible, too:
> >> 
> >> 
> >> root at heimdall:~# xenpm get-cpufreq-para
> >> [CPU0] failed to get cpufreq parameter
> >> [...]
> >> root at heimdall:~# xenpm  get-cpufreq-states
> >> root at heimdall:~# 
> >> 
> >> 
> >> So I guess it could as well make it so that lspci doesn't show
> >> passed-out devices.
> >
> > I am wondering if you are using an older kernel. The xen-acpi-processor
> > driver should be loaded which would give the C and P states to the
> > hypervisor. Which in turn would result in those above commands
> > providing the right data.
> 
> Linux heimdall 3.2.0-4-amd64 #1 SMP Debian 3.2.57-3+deb7u2 x86_64 GNU/Linux
> 
> This is what comes in Debian.  Unfortunately, this kernel crashes when
> I'm copying data to a domU NFS server over the network :((  I need to
> find out how to get some useful information out of it to make a bug
> report.
> 
> How do I know whether the xen-acpi-processor driver is loaded or not?

lsmod

But it looks like v3.4 and later were the kernels that started having
this driver. That would explain why it does not exist as you are using
3.2.

> 
> >> BTW, getting some info in dmesg might be nice, like a message saying
> >> "xen-pciback: device 06:00.0 can be passed through to guests".  We could
> >
> > You just need to boot with 'debug'  - and it should tell you that
> > a device is being assigned to another guest (when assigning). Also
> > at bootup it will tell you that it is seizinging.
> >
> > Just do 'dmesg | grep pciback' and you will get it.
> 
> Ok, I enabled debugging.  Maybe that also helps to get some more info
> about the crashes.
> 
> >> actually see right away if it did work or not.  That a device disappears
> >> isn't too great as indication, especially not when lspci still lists it.
> >> 
> >> Of course, you could use the command (which I don't remember) to show
> >> devices that can be passed through.  But that may just work as well as
> >
> > Such as xl or xm pci-list-assignable?
> 
> yes
> 
> >> 'xenpm get-cpufreq-states':  Apparently, there aren't any CPUs ...
> >
> > See if xen-acpi-processor is loaded or built in.
> 
> Unless it's called "processor", it doesn't seem to exist:
> 
> 
> root at heimdall:~# lsmod |grep proc
> processor              28149  1 acpi_cpufreq
> thermal_sys            18040  1 processor
> root at heimdall:~# grep -i proces /boot/config-3.2.0-4-amd64 |less                                                                                                                                                                             
> root at heimdall:~# find /lib/modules/3.2.0-4-amd64/ -name "*proces*"
> /lib/modules/3.2.0-4-amd64/kernel/drivers/acpi/processor.ko
> root at heimdall:~# find /lib/modules/3.2.0-4-amd64/ -name "*xen*"
> /lib/modules/3.2.0-4-amd64/kernel/drivers/net/xen-netfront.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/net/xen-netback
> /lib/modules/3.2.0-4-amd64/kernel/drivers/net/xen-netback/xen-netback.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/net/ethernet/qlogic/netxen
> /lib/modules/3.2.0-4-amd64/kernel/drivers/net/ethernet/qlogic/netxen/netxen_nic.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/watchdog/xen_wdt.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xen-gntalloc.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xen-gntdev.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xen-evtchn.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xen-pciback
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xen-pciback/xen-pciback.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xenfs
> /lib/modules/3.2.0-4-amd64/kernel/drivers/xen/xenfs/xenfs.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/block/xen-blkfront.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/block/xen-blkback
> /lib/modules/3.2.0-4-amd64/kernel/drivers/block/xen-blkback/xen-blkback.ko
> /lib/modules/3.2.0-4-amd64/kernel/drivers/pci/xen-pcifront.ko
> root at heimdall:~# grep -i proces /boot/config-3.2.0-4-amd64
> CONFIG_BSD_PROCESS_ACCT=y
> CONFIG_BSD_PROCESS_ACCT_V3=y
> # Processor type and features
> CONFIG_ACPI_PROCESSOR=m
> CONFIG_ACPI_PROCESSOR_AGGREGATOR=m
> # Audio decoders, processors and mixers
> root at heimdall:~# grep -i xen /boot/config-3.2.0-4-amd64                                                                                                                                                                                      
> CONFIG_XEN=y
> CONFIG_XEN_DOM0=y
> CONFIG_XEN_PRIVILEGED_GUEST=y
> CONFIG_XEN_PVHVM=y
> CONFIG_XEN_MAX_DOMAIN_MEMORY=128
> CONFIG_XEN_SAVE_RESTORE=y
> # CONFIG_XEN_DEBUG_FS is not set
> CONFIG_MICROCODE_XEN=y
> CONFIG_PCI_XEN=y
> CONFIG_XEN_PCIDEV_FRONTEND=m
> CONFIG_XEN_BLKDEV_FRONTEND=m
> CONFIG_XEN_BLKDEV_BACKEND=m
> CONFIG_NETXEN_NIC=m
> CONFIG_XEN_NETDEV_FRONTEND=m
> CONFIG_XEN_NETDEV_BACKEND=m
> CONFIG_INPUT_XEN_KBDDEV_FRONTEND=y
> CONFIG_HVC_XEN=y
> CONFIG_XEN_WDT=m
> CONFIG_XEN_FBDEV_FRONTEND=y
> # Xen driver support
> CONFIG_XEN_BALLOON=y
> # CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is not set
> CONFIG_XEN_SCRUB_PAGES=y
> CONFIG_XEN_DEV_EVTCHN=m
> CONFIG_XEN_BACKEND=y
> CONFIG_XENFS=m
> CONFIG_XEN_COMPAT_XENFS=y
> CONFIG_XEN_SYS_HYPERVISOR=y
> CONFIG_XEN_XENBUS_FRONTEND=y
> CONFIG_XEN_GNTDEV=m
> CONFIG_XEN_GRANT_DEV_ALLOC=m
> CONFIG_SWIOTLB_XEN=y
> CONFIG_XEN_PCIDEV_BACKEND=m
> root at heimdall:~# 
> 
> 
> -- 
> Knowledge is volatile and fluid.  Software is power.
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