Re: [PATCH v11 0/7] Support x2APIC mode with TCG accelerator

[Bui Quang Minh <minhquangbui99@gmail.com>]

On 12/28/23 22:44, Bui Quang Minh wrote:
> On 12/26/23 16:21, Michael S. Tsirkin wrote:
>> On Mon, Dec 25, 2023 at 11:40:54PM +0700, Bui Quang Minh wrote:
>>> Hi everyone,
>>>
>>> This series implements x2APIC mode in userspace local APIC and the
>>> RDMSR/WRMSR helper to access x2APIC registers in x2APIC mode. Intel 
>>> iommu
>>> and AMD iommu are adjusted to support x2APIC interrupt remapping. 
>>> With this
>>> series, we can now boot Linux kernel into x2APIC mode with TCG 
>>> accelerator
>>> using either Intel or AMD iommu.
>>>
>>> Testing to boot my own built Linux 6.3.0-rc2, the kernel successfully 
>>> boot
>>> with enabled x2APIC and can enumerate CPU with APIC ID 257
>>>
>>> Using Intel IOMMU
>>>
>>> qemu/build/qemu-system-x86_64 \
>>>    -smp 2,maxcpus=260 \
>>>    -cpu qemu64,x2apic=on \
>>>    -machine q35 \
>>>    -device intel-iommu,intremap=on,eim=on \
>>>    -device 
>>> qemu64-x86_64-cpu,x2apic=on,core-id=257,socket-id=0,thread-id=0 \
>>>    -m 2G \
>>>    -kernel $KERNEL_DIR \
>>>    -append "nokaslr console=ttyS0 root=/dev/sda earlyprintk=serial 
>>> net.ifnames=0" \
>>>    -drive file=$IMAGE_DIR,format=raw \
>>>    -nographic \
>>>    -s
>>>
>>> Using AMD IOMMU
>>>
>>> qemu/build/qemu-system-x86_64 \
>>>    -smp 2,maxcpus=260 \
>>>    -cpu qemu64,x2apic=on \
>>>    -machine q35 \
>>>    -device amd-iommu,intremap=on,xtsup=on \
>>>    -device 
>>> qemu64-x86_64-cpu,x2apic=on,core-id=257,socket-id=0,thread-id=0 \
>>>    -m 2G \
>>>    -kernel $KERNEL_DIR \
>>>    -append "nokaslr console=ttyS0 root=/dev/sda earlyprintk=serial 
>>> net.ifnames=0" \
>>>    -drive file=$IMAGE_DIR,format=raw \
>>>    -nographic \
>>>    -s
>>>
>>> Testing the emulated userspace APIC with kvm-unit-tests, disable test
>>> device with this patch
>>
>> Seems to break build for windows/amd64
>> https://gitlab.com/mstredhat/qemu/-/pipelines/1118886361/failures
> 
> I saw the CI test "pages" failed too. On my CI, most of the time, it 
> failed with
> 
> $ htags -anT --tree-view=filetree -m qemu_init -t "Welcome to the QEMU 
> sourcecode"
> 00:24
> htags: Negative exec line limit = -8099
> 
> It only succeeded once. I could not reproduce locally. Do you have any 
> ideas what the problem is?

I think I briefly understand why pages test fails. Internally, htags 
call global to parse the output of gtags. When executing command, it 
expects the size of argv and env to 20*1024 
(https://github.com/harai/gnu-global/blob/f86ba74d867385353815f8656c4a6cf4029c1f0b/libutil/xargs.c#L92-L105). 
The failed test case only happens when the last commit is patch 7 (test: 
bios-tables-test: add IVRS changed binary) which has a very long commit 
message (around 9000 bytes). By default, Gitlab appends some environment 
variables to the runner and one of them is CI_COMMIT_MESSAGE which 
contains the long commit message. So it exceeds the limit of 20*1024 
bytes and fails.

In my opinion, this failed test is not so critical and seems unrelated 
to the series so I skip this failed test. I will post the new version to 
fix the windows/amd64 build soon.

Thanks,
Quang Minh.