Question about the x86_64 SIMD instruction support by qemu-softmmu

[Fengwei Yin]

Hi List,
When I run the Chromium v8 unit test within qmeu-softmmu, following
failure is triggered:

=== cctest/test-gc/RunWasmLiftoff_RefTrivialCasts ===

   [60/149]
#

   # Fatal error in
../../v8/test/cctest/wasm/test-gc.cc, line 109
# Test wasm GC: Wasm SIMD unsupported @+23
#
#

   #
#FailureMessage Object: 0x7fffd540
 C stack trace ===

/mnt/src/chromium/src/out/Default/libv8_libbase.so(v8::base::debug::StackTrace::StackTrace()+0x13)
[0x77fc3403]
/mnt/src/chromium/src/out/Default/libv8_libplatform.so(+0x173ad)
[0x77f713ad]
/mnt/src/chromium/src/out/Default/libv8_libbase.so(V8_Fatal(char
const*, int, char const*, ...)+0x153) [0x77fa5343]
/mnt/src/chromium/src/out/Default/cctest(+0x153f427)
[0x56a93427]

/mnt/src/chromium/src/out/Default/cctest(+0x1547c3e) [0x56a9bc3e]
/mnt/src/chromium/src/out/Default/cctest(+0xd662f3) [0x562ba2f3]
/mnt/src/chromium/src/out/Default/cctest(+0xd67a9c) [0x562bba9c]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xea) [0x74476d0a]
/mnt/src/chromium/src/out/Default/cctest(_start+0x2a) [0x562ba0ba]
Aborted
Command: /mnt/src/chromium/src/out/Default/cctest
test-gc/RunWasmLiftoff_RefTrivialCasts --random-seed=2033349456
--nohard-abort --enable-slow-asserts --verify-heap --testin
g-d8-test-runner

If run it with qemu from Debian bullseye  (with --enable-kvm and --cpu
host) on 10th-generation Cascade Lake, there is no such failure.

The qemu-softmmu was built from following commit:

commit 553032db17440f8de011390e5a1cfddd13751b0b (tag: v5.2.0)
Author: Peter Maydell 
Date:   Tue Dec 8 15:55:19 2020 +

Update version for v5.2.0 release

Signed-off-by: Peter Maydell 

Question: is some SIMD instruction not supported by qemu-softmmu
build? If more information is needed, just let me know. Thanks.


Regards
Yin, Fengwei

How can I use different tcp port other than 1234 to use gdb for application debug on qemu?

[Chan Kim]

Hi all!

I think I knew this but can't remember now..

To connect qemu with gdb, we give -s -S option.

According to manual(https://qemu.readthedocs.io/en/latest/system/gdb.html),
this -s option makes qemu wait for incoming gdb connection at tcp port 1234.

And it says : 

"If you want to specify which TCP port to use or to use something other than
TCP for the gdbstub connection, use the -gdb dev option instead of -s. See

Using unix sockets for an example."

But if I just want to use different port number, but the example doesn't
show how. The -gdb option seems to expect char device. 

I think I have used different port for debugging qemu itself and another
port for the application on it in the past, but forgot how to do it. (can't
find any memo)

How should I do it? (using different port)

Thanks!

Chan Kim

 

RE: How can I use different tcp port other than 1234 to use gdb for application debug on qemu?

[Chan Kim]

Oh, I found it was -gdb tcp::1235.  (I had tried only -gdb tcp:1235)

I think the manual should better have this information there.

 

From: Chan Kim  
Sent: Saturday, January 29, 2022 11:38 AM
To: 'qemu-discuss' 
Subject: How can I use different tcp port other than 1234 to use gdb for
application debug on qemu?

 

Hi all!

I think I knew this but can't remember now..

To connect qemu with gdb, we give -s -S option.

According to manual(https://qemu.readthedocs.io/en/latest/system/gdb.html),
this -s option makes qemu wait for incoming gdb connection at tcp port 1234.

And it says : 

"If you want to specify which TCP port to use or to use something other than
TCP for the gdbstub connection, use the -gdb dev option instead of -s. See

Using unix sockets for an example."

But if I just want to use different port number, but the example doesn't
show how. The -gdb option seems to expect char device. 

I think I have used different port for debugging qemu itself and another
port for the application on it in the past, but forgot how to do it. (can't
find any memo)

How should I do it? (using different port)

Thanks!

Chan Kim