Re: [Xen-devel] lastest xen unstable crash

[Francisco Rocha <f.e.liberal-rocha@xxxxxxxxxxxxxxx>]

________________________________________
From: Jan Beulich [JBeulich@xxxxxxxx]
Sent: 10 April 2012 12:20
To: Francisco Rocha
Cc: xen-devel@xxxxxxxxxxxxx
Subject: Re: [Xen-devel] lastest xen unstable crash

>>> On 10.04.12 at 13:08, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
> In any case, a fundamental question is whether your CPU has
> XSAVE support in the first place, and whether kernel and
> hypervisor disagree about that for some reason. Could you
> for that purpose post /proc/cpuinfo contents from when running
> a native kernel?

Just realized that this question is answered by the log you provided:

(XEN) xstate_init: using cntxt_size: 0x340 and states: 0x7

so indeed the fastest approach (short of someone seeing something
obviously wrong with the code) appears to be to add some tracing to
the CR4 handling (pv_guest_cr4_fixup() and the XSETBV handling in
emulate_privileged_op()), particularly also because the register dump
indicates that the relevant bit was not set in CR4 at the point where
the XSETBV faulted.

Jan

I have added some prints in the functions you mentioned. Is this what you need? 
These are the new lines in the dmesg, the attached file contains the rest.

(XEN) domain.c:691:d0 @pv_guest_cr4_fixup-start: id=0 hv_cr4: 00002660 -> 
guest_cr4:00002660
(XEN) domain.c:707:d0 @pv_guest_cr4_fixup-end: id=0 hv_cr4: 00002660 guest_cr4: 
00002660 return: 00002660
(XEN) domain.c:691:d0 @pv_guest_cr4_fixup-start: id=0 hv_cr4: 00002660 -> 
guest_cr4:00002660
(XEN) domain.c:707:d0 @pv_guest_cr4_fixup-end: id=0 hv_cr4: 00002660 guest_cr4: 
00002660 return: 00002660
(XEN) domain.c:691:d0 @pv_guest_cr4_fixup-start: id=0 hv_cr4: 00002660 -> 
guest_cr4:00002660
(XEN) domain.c:707:d0 @pv_guest_cr4_fixup-end: id=0 hv_cr4: 00002660 guest_cr4: 
00002660 return: 00002660
(XEN) traps.c:2243:d0 @XSETBV: new_xfeature: 0000000000000007
(XEN) traps.c:2246:d0 @XSETBV: (v->arch.pv_vcpu.ctrlreg[4] & X86_CR4_OSXSAVE): 
0000000000000000

Here is the /proc/cpuinfo running on a native kernel:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 42
model name      : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping        : 7
microcode       : 0x25
cpu MHz         : 800.000
cache size      : 4096 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 2
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov 
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm 
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc 
aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr 
pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm 
ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips        : 5382.77
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

and /proc/cpuinfo with dom0 running with xsave=0:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 42
model name      : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping        : 7
microcode       : 0x23
cpu MHz         : 800.000
cache size      : 4096 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 1
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu de tsc msr pae cx8 apic sep cmov pat clflush acpi mmx 
fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl nonstop_tsc 
aperfmperf pni pclmulqdq est ssse3 cx16 sse4_1 sse4_2 x2apic popcnt 
tsc_deadline_timer aes hypervisor lahf_lm ida arat epb pln pts dts
bogomips        : 5382.58
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

Cheers,
Francisco

Attachment: xen_xsave_crash.txt
Description: xen_xsave_crash.txt

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