Re: [PATCH for-8.2 6/7] target/riscv: add 'max' CPU type

[Conor Dooley]

On Wed, Jul 12, 2023 at 06:39:28PM -0300, Daniel Henrique Barboza wrote:
> On 7/12/23 18:35, Conor Dooley wrote:
> > On Wed, Jul 12, 2023 at 06:09:10PM -0300, Daniel Henrique Barboza wrote:
> > 
> > > It is intentional. Those default marchid/mimpid vals were derived from 
> > > the current
> > > QEMU version ID/build and didn't mean much.
> > > 
> > > It is still possible to set them via "-cpu rv64,marchid=N,mimpid=N" if 
> > > needed when
> > > using the generic (rv64,rv32) CPUs. Vendor CPUs can't have their machine 
> > > IDs changed
> > > via command line.
> > 
> > Sounds good, thanks. I did just now go and check icicle to see what it
> > would report & it does not boot. I'll go bisect...
> 
> BTW how are you booting the icicle board nowadays? I remember you mentioning 
> about
> some changes in the FDT being required to boot and whatnot.

I do direct kernel boots, as the HSS doesn't work anymore, and just lie
a bit to QEMU about how much DDR we have.
.PHONY: qemu-icicle
qemu-icicle:
        $(qemu) -M microchip-icicle-kit \
                -m 3G -smp 5 \
                -kernel $(vmlinux_bin) \
                -dtb $(icicle_dtb) \
                -initrd $(initramfs) \
                -display none -serial null \
                -serial stdio \
                -D qemu.log -d unimp

The platform only supports 2 GiB of DDR, not 3, but if I pass 2 to QEMU
it thinks there's 1 GiB at 0x8000_0000 and 1 GiB at 0x10_0000_0000. The
upstream devicetree (and current FPGA reference design) expects there to
be 1 GiB at 0x8000_0000 and 1 GiB at 0x10_4000_0000. If I lie to QEMU,
it thinks there is 1 GiB at 0x8000_0000 and 2 GiB at 0x10_0000_0000, and
things just work. I prefer doing it this way than having to modify the
DT, it is a lot easier to explain to people this way.

I've been meaning to work the support for the icicle & mpfs in QEMU, but
it just gets shunted down the priority list. I'd really like if a proper
boot flow would run in QEMU, which means fixing whatever broke the HSS,
but I've recently picked up maintainership of dt-binding stuff in Linux,
so I've unfortunately got even less time to try and work on it. Maybe
we'll get some new graduate in and I can make them suffer in my stead...

> If it's not too hard I'll add it in my test scripts to keep it under check. 
> Perhaps
> we can even add it to QEMU testsuite.

I don't think it really should be that bad, at least for the direct
kernel boot, which is what I mainly care about, since I use it fairly
often for debugging boot stuff in Linux.

Anyways, aa903cf31391dd505b399627158f1292a6d19896 is the first bad commit:
commit aa903cf31391dd505b399627158f1292a6d19896
Author: Bin Meng <bmeng@tinylab.org>
Date:   Fri Jun 30 23:36:04 2023 +0800

    roms/opensbi: Upgrade from v1.2 to v1.3
    
    Upgrade OpenSBI from v1.2 to v1.3 and the pre-built bios images.

And I see something like:
qemu//build/qemu-system-riscv64 -M microchip-icicle-kit \
        -m 3G -smp 5 \
        -kernel vmlinux.bin \
        -dtb icicle.dtb \
        -initrd initramfs.cpio.gz \
        -display none -serial null \
        -serial stdio \
        -D qemu.log -d unimp
qemu-system-riscv64: warning: disabling zca extension for hart 
0x0000000000000000 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zca extension for hart 
0x0000000000000001 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zcd extension for hart 
0x0000000000000001 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zca extension for hart 
0x0000000000000002 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zcd extension for hart 
0x0000000000000002 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zca extension for hart 
0x0000000000000003 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zcd extension for hart 
0x0000000000000003 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zca extension for hart 
0x0000000000000004 because privilege spec version does not match
qemu-system-riscv64: warning: disabling zcd extension for hart 
0x0000000000000004 because privilege spec version does not match

OpenSBI v1.3
   ____                    _____ ____ _____
  / __ \                  / ____|  _ \_   _|
 | |  | |_ __   ___ _ __ | (___ | |_) || |
 | |  | | '_ \ / _ \ '_ \ \___ \|  _ < | |
 | |__| | |_) |  __/ | | |____) | |_) || |_
  \____/| .__/ \___|_| |_|_____/|___/_____|
        | |
        |_|

init_coldboot: ipi init failed (error -1009)

Just to note, because we use our own firmware that vendors in OpenSBI
and compiles only a significantly cut down number of files from it, we
do not use the fw_dynamic etc flow on our hardware. As a result, we have
not tested v1.3, nor do we have any immediate plans to change our
platform firmware to vendor v1.3 either.

I unless there's something obvious to you, it sounds like I will need to
go and bisect OpenSBI. That's a job for another day though, given the
time.

Cheers,
Conor.

signature.asc
Description: PGP signature