Re: [kvm-unit-tests PATCH v4 04/13] s390x: Switch to z/Arch

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello Janosch!

On 04.01.2019 11:15, Janosch Frank wrote:
On 04.01.19 09:56, Jens Remus wrote:
Hi Janosch,

happy new year!

Thanks, same to you.


On 03.01.2019 11:07, Janosch Frank wrote:
LPAR and z/VM start in esam mode depending on the hardware, so we need

Did you consider the CZAM facility? You already use a so called "short
PSW" (which is compatible to the ESA/390 PSW, as you did not set bit 31).

LPAR and z/VM start in esam or esame mode, depending on the hardware
CZAM facility and z/VM MACHINE setting.

See POP section "Load State":

"When neither the configuration-z/Architecture-architectural-mode (CZAM)
facility nor the ESA/390-compatibility-mode facility are installed, this
sets the architectural mode to the ESA/390 mode. When the
ESA/390-compatibility-mode facility is installed, this sets the
architecture mode to the ESA/390-compatibility mode. When the CZAM
facility is installed, the architectural mode is unchanged (that is, it
remains in the z/Architecture architectural mode)."

to switch to z/Arch and set 64 bit addressing.

I don't really want to test in which state I am and blindly setting
z/Arch and 64 bit is a valid course of action according to the AR.

I completely agree with you. I was rather thinking of enhancing the commit message to make clear that LPAR and z/VM start either in esam or esame mode, depending on the hardware CZAM facility and z/VM MACHINE setting. Re-reading your commit message I must admit that it kind of already contains this with "depending on the hardware" and one may then deduct from the commit subject that it must be z/Arch (esame) otherwise.

Wouldn't it be nice to mention this in the commit subject:

s390x: Switch to z/Arch and 64-bit addressing [mode]

As commented yesterday (Message-ID:
<9644d7ab-d815-720d-f1a1-eee1a6a0c253@xxxxxxxxxxxxx>):
The title will be changed to:
s390x: Switch to z/Arch and enable 64 bit addressing mode

Also I will move the sam64 from the previous patch into this one.


I might add to the comment that we do this no matter what configuration
we start out in, because it doesn't produce an exception.

That would be nice. Thanks!

Regards,
Jens
--
Linux on Z and z/VSE Development & Service (D3229)
IBM Systems & Technology Group, Pure Systems & Modular Software Development

IBM Data Privacy Statement: https://www.ibm.com/privacy/us/en/

IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Matthias Hartmann
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux