Re: [PATCH-for-5.0?] target/ppc: Fix TCG temporary leaks in gen_slbia()

[Dennis Clarke]

On 4/20/20 6:56 PM, Peter Maydell wrote:
> On Fri, 17 Apr 2020 at 10:08, Philippe Mathieu-Daudé <address@hidden> wrote:
> > This fixes:
> >
> >    $ qemu-system-ppc64 \
> >    -machine pseries-4.1 -cpu power9 \
> >    -smp 4 -m 12G -accel tcg ...
> >    ...
> >    Quiescing Open Firmware ...
> >    Booting Linux via __start() @ 0x0000000002000000 ...
> >    Opcode 1f 12 0f 00 (7ce003e4) leaked temporaries
> >    Opcode 1f 12 0f 00 (7ce003e4) leaked temporaries
> >    Opcode 1f 12 0f 00 (7ce003e4) leaked temporaries
> >
> > [*] https://www.mail-archive.com/address@hidden/msg05400.html
> >
> > Fixes: 0418bf78fe8 ("Fix ISA v3.0 (POWER9) slbia implementation")
> > Reported-by: Dennis Clarke <address@hidden>
> > Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
>
> I propose to apply this patch for 5.0 rc4 (as well as the
> ppc pullreq already sent), since the iscsi bugfix means
> we need an rc4 anyway. Any objections?

I have been running rc3 with this patch fine for some days now.  Both 
with and without a debug enabled build wherein the performance 
difference between the two is obvious.

However, I do see warnings from 5.0.0-rc3 that worry me :

$ /usr/local/bin/qemu-system-ppc64 \
> -machine pseries-4.1 -cpu power9 -smp 4 -m 12G -accel tcg \
> -drive file=/home/ppc64/ppc64le.qcow2 \
> -device virtio-net-pci,netdev=usernet \
> -netdev user,id=usernet,hostfwd=tcp::10000-:22 \
> -serial stdio -display none -vga none
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-cfpc=workaround
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-sbbc=workaround
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-ibs=workaround


SLOF **********************************************************************
QEMU Starting
 Build Date = Mar 27 2020 13:57:26
 FW Version = git-8e012d6fddb62be8
 Press "s" to enter Open Firmware.

Populating /vdevice methods
Populating /vdevice/vty@71000000
Populating /vdevice/nvram@71000001
Populating /vdevice/v-scsi@71000002
       SCSI: Looking for devices
          8000000000000000 DISK     : "QEMU     QEMU HARDDISK    2.5+"
          8200000000000000 CD-ROM   : "QEMU     QEMU CD-ROM      2.5+"
Populating /pci@800000020000000
                     00 0000 (D) : 1af4 1000    virtio [ net ]
No NVRAM common partition, re-initializing...
Scanning USB
Using default console: /vdevice/vty@71000000

  Welcome to Open Firmware

  Copyright (c) 2004, 2017 IBM Corporation All rights reserved.
  This program and the accompanying materials are made available
  under the terms of the BSD License available at
  http://www.opensource.org/licenses/bsd-license.php


Trying to load:  from: /vdevice/v-scsi@71000002/disk@8000000000000000 
...   Successfully loaded


etc etc etc

What shall I do with "TCG doesn't support requested feature, 
cap-cfpc=workaround" ??

--
Dennis Clarke
RISC-V/SPARC/PPC/ARM/CISC
UNIX and Linux spoken
GreyBeard and suspenders optional