Re: [PATCH] rcutorture: Add basic ARM64 support to run scripts

From: Lihao Liang
Date: Tue Dec 12 2017 - 04:29:55 EST


Hi Paul,

Many thanks for your helpful comments! I have addressed all of them in a new version of the patch, which is sent out in a separate email.

If you have further comments, please let me know.

Best regards,
Lihao.

On 2017/12/12 0:32, Paul E. McKenney wrote:
> On Fri, Dec 08, 2017 at 06:13:43PM +0800, lianglihao@xxxxxxxxxx wrote:
>> From: Lihao Liang <lianglihao@xxxxxxxxxx>
>>
>> This commit adds support of the qemu command qemu-system-aarch64
>> to rcutorture. Use the following command to run:
>>
>> ./kvm.sh --qemu-cmd qemu-system-aarch64
>>
>> Signed-off-by: Lihao Liang <lianglihao@xxxxxxxxxx>
>
> Nice!!! Getting ARM support for rcutorture has been on my todo list
> for some time!
>
> A few questions and comments below.
>
> Feedback from ARM experts also welcome!
>
> Thanx, Paul
>
>> ---
>>
>> The max CPUs supported by qemu machine 'virt' is 8 so the value of
>> CONFIG_NR_CPUS in some test configuration files needs to be adjusted.
>>
>> tools/testing/selftests/rcutorture/bin/functions.sh | 18 +++++++++++++++++-
>> 1 file changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
>> index 07a1377..5ffe4fe 100644
>> --- a/tools/testing/selftests/rcutorture/bin/functions.sh
>> +++ b/tools/testing/selftests/rcutorture/bin/functions.sh
>> @@ -136,6 +136,9 @@ identify_boot_image () {
>> qemu-system-x86_64|qemu-system-i386)
>> echo arch/x86/boot/bzImage
>> ;;
>> + qemu-system-aarch64)
>> + echo arch/arm64/boot/Image
>> + ;;
>> *)
>> echo vmlinux
>> ;;
>
> Is it possible to automatically select ARM based on the kernel binary?
> See the identify_qemu function for how this is done for i386, x86_64,
> and PowerPC. Can an "elif" be added for ARM?
>
>> @@ -185,7 +188,14 @@ identify_qemu_append () {
>> then
>> echo root=/dev/sda
>> else
>> - echo console=ttyS0
>> + case "$1" in
>> + qemu-system-aarch64)
>> + echo console=ttyAMA0
>> + ;;
>> + *)
>> + echo console=ttyS0
>> + ;;
>> + esac
>> fi
>> }
>
> This approach is going to result in very ugly nesting if support is
> added for additional CPU families. How about something like this?
>
> identify_qemu_append () {
> local console=ttyS0
>
> case "$1" in
> qemu-system-x86_64|qemu-system-i386)
> echo noapic selinux=0 initcall_debug debug
> ;;
> qemu-system-aarch64)
> console=ttyAMA0
> ;;
> esac
> if test -n "$TORTURE_QEMU_INTERACTIVE"
> then
> echo root=/dev/sda
> else
> echo console=$console
> fi
> }
>
>> @@ -197,6 +207,9 @@ identify_qemu_args () {
>> case "$1" in
>> qemu-system-x86_64|qemu-system-i386)
>> ;;
>> + qemu-system-aarch64)
>> + echo -M virt -cpu host
>> + ;;
>> qemu-system-ppc64)
>> echo -enable-kvm -M pseries -nodefaults
>> echo -device spapr-vscsi
>> @@ -257,6 +270,9 @@ specify_qemu_cpus () {
>> qemu-system-x86_64|qemu-system-i386)
>
> How about the following instead, eliminating the need for an additional
> case?
>
> qemu-system-x86_64|qemu-system-i386!qemu-system-aarch64)
>
>> echo $2 -smp $3
>> ;;
>> + qemu-system-aarch64)
>> + echo $2 -smp $3
>> + ;;
>> qemu-system-ppc64)
>> nt="`lscpu | grep '^NUMA node0' | sed -e 's/^[^,]*,\([0-9]*\),.*$/\1/'`"
>> echo $2 -smp cores=`expr \( $3 + $nt - 1 \) / $nt`,threads=$nt
>> --
>> 2.7.4
>>
>
>
> .
>