Re: [PATCH v3 5/6] target/arm: Do memory type alignment check when translation disabled

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Wed, 17 Apr 2024 13:07:35 -0700
Richard Henderson <richard.henderson@linaro.org> wrote:

> On 4/16/24 08:11, Jonathan Cameron wrote:
> > On Fri,  1 Mar 2024 10:41:09 -1000
> > Richard Henderson <richard.henderson@linaro.org> wrote:
> >   
> >> If translation is disabled, the default memory type is Device, which
> >> requires alignment checking.  This is more optimally done early via
> >> the MemOp given to the TCG memory operation.
> >>
> >> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> >> Reported-by: Idan Horowitz <idan.horowitz@gmail.com>
> >> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1204
> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>  
> > 
> > Hi Richard.
> > 
> > I noticed some tests I was running stopped booting with master.
> > (it's a fun and complex stack of QEMU + kvm on QEMU for vCPU Hotplug kernel work,
> > but this is the host booting)
> > 
> > EDK2 build from upstream as of somepoint last week.
> > 
> > Bisects to this patch.
> > 
> >   qemu-system-aarch64 -M virt,gic-version=3,virtualization=true -m 4g,maxmem=8G,slots=8 -cpu cortex-a76 -smp cpus=4,threads=2,clusters=2,sockets=1 \
> >   -kernel Image \
> >   -drive if=none,file=full.qcow2,format=qcow2,id=hd \
> >   -device ioh3420,id=root_port1 -device virtio-blk-pci,drive=hd \
> >   -netdev user,id=mynet,hostfwd=tcp::5555-:22 -device virtio-net-pci,netdev=mynet,id=bob \
> >   -nographic -no-reboot -append 'earlycon root=/dev/vda2 fsck.mode=skip tp_printk' \
> >   -monitor telnet:127.0.0.1:1235,server,nowait -bios QEMU_EFI.fd \
> >   -object memory-backend-ram,size=4G,id=mem0 \
> >   -numa node,nodeid=0,cpus=0-3,memdev=mem0
> > 
> > Symptoms: Nothing on console from edk2 which is built in debug mode so is normally very noisy.
> >            No sign of anything much happening at all :(  
> 
> This isn't a fantastic bug report.
> 
> (1) If it doesn't boot efi, then none of the -kernel parameters are necessary.
> (2) I'd be surprised if the full.qcow2 drive parameters are necessary either.
>      But if they are, what contents?  Is a new empty drive sufficient, just
>      enough to send the bios through the correct device initialization?
> (3) edk2 build from ...
>      Well, this is partly edk2's fault, as the build documentation is awful.
>      I spent an entire afternoon trying to figure it out and gave up.
> 
> I will say that the edk2 shipped with qemu does work, so... are you absolutely
> certain that it isn't a bug in edk2 since then?  Firmware bugs are exactly what
> that patch is supposed to expose, as requested by issue #1204.
> 
> I'd say you should boot with "-d int" and see what kind of interrupts you're getting very 
> early on.  I suspect that you'll see data aborts with ESR xx/yy where the last 6 bits of 
> yy are 0x21 (alignment fault).

Hi Richard,

Sorry for lack of details, I was aware it wasn't great and should have stated I planned
to come back with more details when I had time to debug.  Snowed under so for now I've
just dropped back to 8.2 and will get back to this perhaps next week.

Jonathan

> 
> 
> r~