CentOS virt - Sep 2017 - Xen CentOS 7.3 server + CentOS 7.3 VM fails to boot after CR updates (applied to VM)!

On 09/05/2017 02:26 PM, Kevin Stange wrote:
> On 09/04/2017 05:27 PM, Johnny Hughes wrote:
>> On 09/04/2017 03:59 PM, Kevin Stange wrote:
>>> On 09/02/2017 08:11 AM, Johnny Hughes wrote:
>>>> On 09/01/2017 02:41 PM, Kevin Stange wrote:
>>>>> On 08/31/2017 07:50 AM, PJ Welsh wrote:
>>>>>> A recently created and fully functional CentOS 7.3 VM
fails to boot
>>>>>> after applying CR updates:
>>>>> <snip>
>>>>>> Server OS is CentOS 7.3 using Xen (no CR updates):
>>>>>> rpm -qa xen\*
>>>>>> xen-hypervisor-4.6.3-15.el7.x86_64
>>>>>> xen-4.6.3-15.el7.x86_64
>>>>>> xen-licenses-4.6.3-15.el7.x86_64
>>>>>> xen-libs-4.6.3-15.el7.x86_64
>>>>>> xen-runtime-4.6.3-15.el7.x86_64
>>>>>>
>>>>>> uname -a
>>>>>> Linux tsxen2.xx.com <http://tsxen2.xx.com>
4.9.39-29.el7.x86_64 #1 SMP
>>>>>> Fri Jul 21 15:09:00 UTC 2017 x86_64 x86_64 x86_64
GNU/Linux
>>>>>>
>>>>>> Sadly, the other issue is that the grub menu will not
display for me to
>>>>>> select another kernel to see if it is just a kernel
issue.
>>>>>>
>>>>>> The dracut prompt does not show any /dev/disk folder
either.
>>>>>>
>>>>>
>>>>> I'm seeing this as well.  My host is 4.9.44-29 and Xen
4.4.4-26 from
>>>>> testing repo, my guest is 3.10.0-693.1.1.  Guest boots fine
with
>>>>> 514.26.2.  The kernel messages that appear to kick off the
failure for
>>>>> me start with a page allocation failure.  It eventually
reaches dracut
>>>>> failures due to systemd/udev not setting up properly, but I
think the
>>>>> root is this:
>>>>>
>>>>> [    1.970630] ------------[ cut here ]------------
>>>>> [    1.970651] WARNING: CPU: 2 PID: 225 at mm/vmalloc.c:131
>>>>> vmap_page_range_noflush+0x2c1/0x350
>>>>> [    1.970660] Modules linked in:
>>>>> [    1.970668] CPU: 2 PID: 225 Comm: systemd-udevd Not
tainted
>>>>> 3.10.0-693.1.1.el7.x86_64 #1
>>>>> [    1.970677]  0000000000000000 000000008cddc75d
ffff8803e8587bd8
>>>>> ffffffff816a3d91
>>>>> [    1.970688]  ffff8803e8587c18 ffffffff810879c8
00000083811c14e8
>>>>> ffff8800066eb000
>>>>> [    1.970698]  0000000000000001 ffff8803e86d6940
ffffffffc0000000
>>>>> 0000000000000000
>>>>> [    1.970708] Call Trace:
>>>>> [    1.970725]  [<ffffffff816a3d91>]
dump_stack+0x19/0x1b
>>>>> [    1.970736]  [<ffffffff810879c8>]
__warn+0xd8/0x100
>>>>> [    1.970742]  [<ffffffff81087b0d>]
warn_slowpath_null+0x1d/0x20
>>>>> [    1.970748]  [<ffffffff811c0781>]
vmap_page_range_noflush+0x2c1/0x350
>>>>> [    1.970758]  [<ffffffff811c083e>]
map_vm_area+0x2e/0x40
>>>>> [    1.970765]  [<ffffffff811c1590>]
__vmalloc_node_range+0x170/0x270
>>>>> [    1.970774]  [<ffffffff810fe754>] ?
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.970781]  [<ffffffff810fe754>] ?
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.970792]  [<ffffffff8105f143>]
module_alloc+0x73/0xd0
>>>>> [    1.970798]  [<ffffffff810fe754>] ?
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.970804]  [<ffffffff810fe754>]
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.970811]  [<ffffffff810ff2d2>]
load_module+0xb02/0x29e0
>>>>> [    1.970817]  [<ffffffff811c0717>] ?
vmap_page_range_noflush+0x257/0x350
>>>>> [    1.970823]  [<ffffffff811c083e>] ?
map_vm_area+0x2e/0x40
>>>>> [    1.970829]  [<ffffffff811c1590>] ?
__vmalloc_node_range+0x170/0x270
>>>>> [    1.970838]  [<ffffffff81101249>] ?
SyS_init_module+0x99/0x110
>>>>> [    1.970846]  [<ffffffff81101275>]
SyS_init_module+0xc5/0x110
>>>>> [    1.970856]  [<ffffffff816b4fc9>]
system_call_fastpath+0x16/0x1b
>>>>> [    1.970862] ---[ end trace 2117480876ed90d2 ]---
>>>>> [    1.970869] vmalloc: allocation failure, allocated 24576
of 28672 bytes
>>>>> [    1.970874] systemd-udevd: page allocation failure:
order:0, mode:0xd2
>>>>> [    1.970883] CPU: 2 PID: 225 Comm: systemd-udevd Tainted:
G        W
>>>>>    ------------   3.10.0-693.1.1.el7.x86_64 #1
>>>>> [    1.970894]  00000000000000d2 000000008cddc75d
ffff8803e8587c48
>>>>> ffffffff816a3d91
>>>>> [    1.970910]  ffff8803e8587cd8 ffffffff81188810
ffffffff8190ea38
>>>>> ffff8803e8587c68
>>>>> [    1.970923]  ffffffff00000018 ffff8803e8587ce8
ffff8803e8587c88
>>>>> 000000008cddc75d
>>>>> [    1.970939] Call Trace:
>>>>> [    1.970946]  [<ffffffff816a3d91>]
dump_stack+0x19/0x1b
>>>>> [    1.970961]  [<ffffffff81188810>]
warn_alloc_failed+0x110/0x180
>>>>> [    1.970971]  [<ffffffff811c1654>]
__vmalloc_node_range+0x234/0x270
>>>>> [    1.970981]  [<ffffffff810fe754>] ?
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.970989]  [<ffffffff810fe754>] ?
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.970999]  [<ffffffff8105f143>]
module_alloc+0x73/0xd0
>>>>> [    1.971031]  [<ffffffff810fe754>] ?
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.971038]  [<ffffffff810fe754>]
module_alloc_update_bounds+0x14/0x70
>>>>> [    1.971046]  [<ffffffff810ff2d2>]
load_module+0xb02/0x29e0
>>>>> [    1.971052]  [<ffffffff811c0717>] ?
vmap_page_range_noflush+0x257/0x350
>>>>> [    1.971061]  [<ffffffff811c083e>] ?
map_vm_area+0x2e/0x40
>>>>> [    1.971067]  [<ffffffff811c1590>] ?
__vmalloc_node_range+0x170/0x270
>>>>> [    1.971075]  [<ffffffff81101249>] ?
SyS_init_module+0x99/0x110
>>>>> [    1.971081]  [<ffffffff81101275>]
SyS_init_module+0xc5/0x110
>>>>> [    1.971088]  [<ffffffff816b4fc9>]
system_call_fastpath+0x16/0x1b
>>>>> [    1.971094] Mem-Info:
>>>>> [    1.971103] active_anon:875 inactive_anon:2049
isolated_anon:0
>>>>> [    1.971103]  active_file:791 inactive_file:8841
isolated_file:0
>>>>> [    1.971103]  unevictable:0 dirty:0 writeback:0
unstable:0
>>>>> [    1.971103]  slab_reclaimable:1732
slab_unreclaimable:1629
>>>>> [    1.971103]  mapped:1464 shmem:2053 pagetables:480
bounce:0
>>>>> [    1.971103]  free:4065966 free_pcp:763 free_cma:0
>>>>> [    1.971131] Node 0 DMA free:15912kB min:12kB low:12kB
high:16kB
>>>>> active_anon:0kB inactive_anon:0kB active_file:0kB
inactive_file:0kB
>>>>> unevictable:0kB isolated(anon):0kB isolated(file):0kB
present:15996kB
>>>>> managed:15912kB mlocked:0kB dirty:0kB writeback:0kB
mapped:0kB shmem:0kB
>>>>> slab_reclaimable:0kB slab_unreclaimable:0kB
kernel_stack:0kB
>>>>> pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB
local_pcp:0kB
>>>>> free_cma:0kB writeback_tmp:0kB pages_scanned:0
all_unreclaimable? no
>>>>> [    1.971217] lowmem_reserve[]: 0 4063 16028 16028
>>>>> [    1.971226] Node 0 DMA32 free:4156584kB min:4104kB
low:5128kB
>>>>> high:6156kB active_anon:952kB inactive_anon:1924kB
active_file:0kB
>>>>> inactive_file:0kB unevictable:0kB isolated(anon):0kB
isolated(file):0kB
>>>>> present:4177920kB managed:4162956kB mlocked:0kB dirty:0kB
writeback:0kB
>>>>> mapped:4kB shmem:1928kB slab_reclaimable:240kB
slab_unreclaimable:504kB
>>>>> kernel_stack:32kB pagetables:592kB unstable:0kB bounce:0kB
>>>>> free_pcp:1760kB local_pcp:288kB free_cma:0kB
writeback_tmp:0kB
>>>>> pages_scanned:0 all_unreclaimable? no
>>>>> [    1.971264] lowmem_reserve[]: 0 0 11964 11964
>>>>> [    1.971273] Node 0 Normal free:12091564kB min:12088kB
low:15108kB
>>>>> high:18132kB active_anon:2352kB inactive_anon:6272kB
active_file:3164kB
>>>>> inactive_file:35364kB unevictable:0kB isolated(anon):0kB
>>>>> isolated(file):0kB present:12591104kB managed:12251788kB
mlocked:0kB
>>>>> dirty:0kB writeback:0kB mapped:5852kB shmem:6284kB
>>>>> slab_reclaimable:6688kB slab_unreclaimable:6012kB
kernel_stack:880kB
>>>>> pagetables:1328kB unstable:0kB bounce:0kB free_pcp:1196kB
>>>>> local_pcp:152kB free_cma:0kB writeback_tmp:0kB
pages_scanned:0
>>>>> all_unreclaimable? no
>>>>> [    1.971309] lowmem_reserve[]: 0 0 0 0
>>>>> [    1.971316] Node 0 DMA: 0*4kB 1*8kB (U) 0*16kB 1*32kB
(U) 2*64kB (U)
>>>>> 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M)
3*4096kB (M) >>>>> 15912kB
>>>>> [    1.971343] Node 0 DMA32: 7*4kB (M) 18*8kB (UM) 7*16kB
(EM) 3*32kB
>>>>> (EM) 1*64kB (E) 2*128kB (UM) 1*256kB (E) 4*512kB (UM)
4*1024kB (UEM)
>>>>> 4*2048kB (EM) 1011*4096kB (M) = 4156348kB
>>>>> [    1.971377] Node 0 Normal: 64*4kB (UEM) 10*8kB (UEM)
6*16kB (EM)
>>>>> 3*32kB (EM) 3*64kB (UE) 3*128kB (UEM) 1*256kB (E) 2*512kB
(UE) 0*1024kB
>>>>> 1*2048kB (M) 2951*4096kB (M) = 12091728kB
>>>>> [    1.971413] Node 0 hugepages_total=0 hugepages_free=0
>>>>> hugepages_surp=0 hugepages_size=2048kB
>>>>> [    1.971425] 11685 total pagecache pages
>>>>> [    1.971430] 0 pages in swap cache
>>>>> [    1.971437] Swap cache stats: add 0, delete 0, find 0/0
>>>>> [    1.971444] Free swap  = 0kB
>>>>> [    1.971451] Total swap = 0kB
>>>>> [    1.971456] 4196255 pages RAM
>>>>> [    1.971462] 0 pages HighMem/MovableOnly
>>>>> [    1.971467] 88591 pages reserved
>>>>>
>>>>
>>>> Do any of you guys have access to RHEL to try the RHEL 7.4
Kernel?
>>>
>>> I think I may.  I haven't tried yet, but I'll see if I can
get my hands
>>> on one and test it tomorrow when I'm back at the office
tomorrow.
>>>
>>> RH closed my bug as "WONTFIX" so far, saying Red Hat
Quality Engineering
>>> Management declined the request.  I started to look at the Red Hat
>>> source browser to see the list of patches from 693 to 514, but
getting
>>> the full list seems impossible because the change log only goes
back to
>>> 644 and there doesn't seem to be a way to obtain full builds of
>>> unreleased kernels.  Unless I'm mistaken.
>>>
>>> I will also do some digging via RH support if I can.
>>>
>> I would think that RH would want AWS support for RHEL 7.4 and I thought
>> AWS was run on Xen // Note:  I could be wrong about that.
>>
>> In any event, at the very least, we can make a kernel that boots PV for
>> 7.4 at some point.
> 
> AWS does run on Xen, but the modifications they make to Xen are not
> known to me nor which version of Xen they use.  They may also run the
> domains as HVM, which seems to mitigate the issue here.
> 
> I just verified this kernel issue exists on a RHEL 7.3 system image
> under the same conditions, when it's updated to RHEL 7.4 and kernel
> 3.10.0-693.2.1.el7.x86_64.
> 
One other option is to run the DomU's as PVHVM:
https://wiki.xen.org/wiki/Xen_Linux_PV_on_HVM_drivers

That should be much better performance than HVM and may be a workable
solution for people who don't want to modify their VM kernel.

Here is more info on PVHVM:
https://wiki.xen.org/wiki/PV_on_HVM

===============Also heard from someone to try this Config file change to the
base
kernel and rebuild:

CONFIG_RANDOMIZE_BASE=n

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On 09/06/2017 08:40 AM, Johnny Hughes wrote:
> On 09/05/2017 02:26 PM, Kevin Stange wrote:
>> On 09/04/2017 05:27 PM, Johnny Hughes wrote:
>>> On 09/04/2017 03:59 PM, Kevin Stange wrote:
>>>> On 09/02/2017 08:11 AM, Johnny Hughes wrote:
>>>>> On 09/01/2017 02:41 PM, Kevin Stange wrote:
>>>>>> On 08/31/2017 07:50 AM, PJ Welsh wrote:
>>>>>>> A recently created and fully functional CentOS 7.3
VM fails to boot
>>>>>>> after applying CR updates:
>>>>>> <snip>
>>>>>>> Server OS is CentOS 7.3 using Xen (no CR updates):
>>>>>>> rpm -qa xen\*
>>>>>>> xen-hypervisor-4.6.3-15.el7.x86_64
>>>>>>> xen-4.6.3-15.el7.x86_64
>>>>>>> xen-licenses-4.6.3-15.el7.x86_64
>>>>>>> xen-libs-4.6.3-15.el7.x86_64
>>>>>>> xen-runtime-4.6.3-15.el7.x86_64
>>>>>>>
>>>>>>> uname -a
>>>>>>> Linux tsxen2.xx.com <http://tsxen2.xx.com>
4.9.39-29.el7.x86_64 #1 SMP
>>>>>>> Fri Jul 21 15:09:00 UTC 2017 x86_64 x86_64 x86_64
GNU/Linux
>>>>>>>
>>>>>>> Sadly, the other issue is that the grub menu will
not display for me to
>>>>>>> select another kernel to see if it is just a kernel
issue.
>>>>>>>
>>>>>>> The dracut prompt does not show any /dev/disk
folder either.
>>>>>>>
>>>>>>
>>>>>> I'm seeing this as well.  My host is 4.9.44-29 and
Xen 4.4.4-26 from
>>>>>> testing repo, my guest is 3.10.0-693.1.1.  Guest boots
fine with
>>>>>> 514.26.2.  The kernel messages that appear to kick off
the failure for
>>>>>> me start with a page allocation failure.  It eventually
reaches dracut
>>>>>> failures due to systemd/udev not setting up properly,
but I think the
>>>>>> root is this:
>>>>>>
<snip>
>>>>>
>>>>> Do any of you guys have access to RHEL to try the RHEL 7.4
Kernel?
>>>>
>>>> I think I may.  I haven't tried yet, but I'll see if I
can get my hands
>>>> on one and test it tomorrow when I'm back at the office
tomorrow.
>>>>
>>>> RH closed my bug as "WONTFIX" so far, saying Red Hat
Quality Engineering
>>>> Management declined the request.  I started to look at the Red
Hat
>>>> source browser to see the list of patches from 693 to 514, but
getting
>>>> the full list seems impossible because the change log only goes
back to
>>>> 644 and there doesn't seem to be a way to obtain full
builds of
>>>> unreleased kernels.  Unless I'm mistaken.
>>>>
>>>> I will also do some digging via RH support if I can.
>>>>
>>> I would think that RH would want AWS support for RHEL 7.4 and I
thought
>>> AWS was run on Xen // Note:  I could be wrong about that.
>>>
>>> In any event, at the very least, we can make a kernel that boots PV
for
>>> 7.4 at some point.
>>
>> AWS does run on Xen, but the modifications they make to Xen are not
>> known to me nor which version of Xen they use.  They may also run the
>> domains as HVM, which seems to mitigate the issue here.
>>
>> I just verified this kernel issue exists on a RHEL 7.3 system image
>> under the same conditions, when it's updated to RHEL 7.4 and kernel
>> 3.10.0-693.2.1.el7.x86_64.
>>
> 
> One other option is to run the DomU's as PVHVM:
> https://wiki.xen.org/wiki/Xen_Linux_PV_on_HVM_drivers
> 
> That should be much better performance than HVM and may be a workable
> solution for people who don't want to modify their VM kernel.
> 
> Here is more info on PVHVM:
> https://wiki.xen.org/wiki/PV_on_HVM
> 
> ===============> Also heard from someone to try this Config file change
to the base
> kernel and rebuild:
> 
> CONFIG_RANDOMIZE_BASE=n
This suggestion was mirrored in the RH bugzilla as well, it worked, but
the same issue does not exist in newer kernels which have the option on.
 I've posted updated findings in the CentOS bug, which includes a patch
that I found which seems to fix the issue:

https://bugs.centos.org/view.php?id=13763#c30014

-- 
Kevin Stange
Chief Technology Officer
Steadfast | Managed Infrastructure, Datacenter and Cloud Services
800 S Wells, Suite 190 | Chicago, IL 60607
312.602.2689 X203 | Fax: 312.602.2688
kevin at steadfast.net | www.steadfast.net

On 09/06/2017 05:21 PM, Kevin Stange wrote:
> On 09/06/2017 08:40 AM, Johnny Hughes wrote:
>> On 09/05/2017 02:26 PM, Kevin Stange wrote:
>>> On 09/04/2017 05:27 PM, Johnny Hughes wrote:
>>>> On 09/04/2017 03:59 PM, Kevin Stange wrote:
>>>>> On 09/02/2017 08:11 AM, Johnny Hughes wrote:
>>>>>> On 09/01/2017 02:41 PM, Kevin Stange wrote:
>>>>>>> On 08/31/2017 07:50 AM, PJ Welsh wrote:
>>>>>>>> A recently created and fully functional CentOS
7.3 VM fails to boot
>>>>>>>> after applying CR updates:
>>>>>>> <snip>
>>>>>>>> Server OS is CentOS 7.3 using Xen (no CR
updates):
>>>>>>>> rpm -qa xen\*
>>>>>>>> xen-hypervisor-4.6.3-15.el7.x86_64
>>>>>>>> xen-4.6.3-15.el7.x86_64
>>>>>>>> xen-licenses-4.6.3-15.el7.x86_64
>>>>>>>> xen-libs-4.6.3-15.el7.x86_64
>>>>>>>> xen-runtime-4.6.3-15.el7.x86_64
>>>>>>>>
>>>>>>>> uname -a
>>>>>>>> Linux tsxen2.xx.com
<http://tsxen2.xx.com> 4.9.39-29.el7.x86_64 #1 SMP
>>>>>>>> Fri Jul 21 15:09:00 UTC 2017 x86_64 x86_64
x86_64 GNU/Linux
>>>>>>>>
>>>>>>>> Sadly, the other issue is that the grub menu
will not display for me to
>>>>>>>> select another kernel to see if it is just a
kernel issue.
>>>>>>>>
>>>>>>>> The dracut prompt does not show any /dev/disk
folder either.
>>>>>>>>
>>>>>>>
>>>>>>> I'm seeing this as well.  My host is 4.9.44-29
and Xen 4.4.4-26 from
>>>>>>> testing repo, my guest is 3.10.0-693.1.1.  Guest
boots fine with
>>>>>>> 514.26.2.  The kernel messages that appear to kick
off the failure for
>>>>>>> me start with a page allocation failure.  It
eventually reaches dracut
>>>>>>> failures due to systemd/udev not setting up
properly, but I think the
>>>>>>> root is this:
>>>>>>>
> <snip>
>>>>>>
>>>>>> Do any of you guys have access to RHEL to try the RHEL
7.4 Kernel?
>>>>>
>>>>> I think I may.  I haven't tried yet, but I'll see
if I can get my hands
>>>>> on one and test it tomorrow when I'm back at the office
tomorrow.
>>>>>
>>>>> RH closed my bug as "WONTFIX" so far, saying Red
Hat Quality Engineering
>>>>> Management declined the request.  I started to look at the
Red Hat
>>>>> source browser to see the list of patches from 693 to 514,
but getting
>>>>> the full list seems impossible because the change log only
goes back to
>>>>> 644 and there doesn't seem to be a way to obtain full
builds of
>>>>> unreleased kernels.  Unless I'm mistaken.
>>>>>
>>>>> I will also do some digging via RH support if I can.
>>>>>
>>>> I would think that RH would want AWS support for RHEL 7.4 and I
thought
>>>> AWS was run on Xen // Note:  I could be wrong about that.
>>>>
>>>> In any event, at the very least, we can make a kernel that
boots PV for
>>>> 7.4 at some point.
>>>
>>> AWS does run on Xen, but the modifications they make to Xen are not
>>> known to me nor which version of Xen they use.  They may also run
the
>>> domains as HVM, which seems to mitigate the issue here.
>>>
>>> I just verified this kernel issue exists on a RHEL 7.3 system image
>>> under the same conditions, when it's updated to RHEL 7.4 and
kernel
>>> 3.10.0-693.2.1.el7.x86_64.
>>>
>>
>> One other option is to run the DomU's as PVHVM:
>> https://wiki.xen.org/wiki/Xen_Linux_PV_on_HVM_drivers
>>
>> That should be much better performance than HVM and may be a workable
>> solution for people who don't want to modify their VM kernel.
>>
>> Here is more info on PVHVM:
>> https://wiki.xen.org/wiki/PV_on_HVM
>>
>> ===============>> Also heard from someone to try this Config file
change to the base
>> kernel and rebuild:
>>
>> CONFIG_RANDOMIZE_BASE=n
> 
> This suggestion was mirrored in the RH bugzilla as well, it worked, but
> the same issue does not exist in newer kernels which have the option on.
>  I've posted updated findings in the CentOS bug, which includes a patch
> that I found which seems to fix the issue:
> 
> https://bugs.centos.org/view.php?id=13763#c30014
With many thanks to hughesjr and toracat, I was able to find a patch
that seems to resolve this issue and get it into CentOS Plus
3.10.0-693.2.1.  I've asked Red Hat to apply it to some future kernel
update, but that is only a dream for now.

In the meantime, if anyone who has been experiencing the issue with PV
domains can try out the CentOS Plus kernel here and provide feedback,
I'd appreciate it!

https://buildlogs.centos.org/c7-plus/kernel-plus/20170907163005/3.10.0-693.2.1.el7.centos.plus.x86_64/

-- 
Kevin Stange
Chief Technology Officer
Steadfast | Managed Infrastructure, Datacenter and Cloud Services
800 S Wells, Suite 190 | Chicago, IL 60607
312.602.2689 X203 | Fax: 312.602.2688
kevin at steadfast.net | www.steadfast.net

On Wed, Sep 6, 2017 at 8:40 AM, Johnny Hughes <johnny at centos.org>
wrote:
> On 09/05/2017 02:26 PM, Kevin Stange wrote:
> > On 09/04/2017 05:27 PM, Johnny Hughes wrote:
> >> On 09/04/2017 03:59 PM, Kevin Stange wrote:
> >>> On 09/02/2017 08:11 AM, Johnny Hughes wrote:
> >>>> On 09/01/2017 02:41 PM, Kevin Stange wrote:
> >>>>> On 08/31/2017 07:50 AM, PJ Welsh wrote:
> >>>>>> A recently created and fully functional CentOS 7.3
VM fails to boot
> >>>>>> after applying CR updates:
> ...
> One other option is to run the DomU's as PVHVM:
> https://wiki.xen.org/wiki/Xen_Linux_PV_on_HVM_drivers
>
> That should be much better performance than HVM and may be a workable
> solution for people who don't want to modify their VM kernel.
>
> Here is more info on PVHVM:
> https://wiki.xen.org/wiki/PV_on_HVM
>
> ===============> Also heard from someone to try this Config file change
to the base
> kernel and rebuild:
>
> CONFIG_RANDOMIZE_BASE=n
> ...

The referenced link (https://wiki.xen.org/wiki/Xen_Linux_PV_on_HVM_drivers)
looks to be about adding to the older configuration style file. I do not
see the proper incantation for the " xen_platform_pci=1" in the domain
xml
file syntax. I'm not even sure if I attempted it correctly. Is there a
portion of that page that pertains explicitly to booting? I think I missed
something.

Thanks
PJ
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