Qemu qurt and fastrpc?

Qemu qurt and fastrpc?

[Dr. David Alan Gilbert]

Hi Brian,
  I tried your hexagon support booting qurt images, very nice!
I did:

  ./qemu-system-hexagon -M virt  -kernel ./qccdsp8380.mbn -nographic

and got something believable.

  Do you have glue that lets you run comms to the emulated qurt via
fastrpc in the same way that, say a Llama running on a normal
Linux host would?
  It feels useful for debugging/watching what maths kernels are
doing.

  (Not urgent, I'm just trying to get my head around it on my
X1 laptop)

  Thanks in advance,

Dave
-- 
 -----Open up your eyes, open up your mind, open up your code -------   
/ Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
\        dave @ treblig.org |                               | In Hex /
 \ _________________________|_____ http://www.treblig.org   |_______/

Re: Qemu qurt and fastrpc?

[Mohamed Mediouni]

> On 1. Nov 2026, at 23:05, Dr. David Alan Gilbert <dave@treblig.org> wrote:
> 
> Hi Brian,
>  I tried your hexagon support booting qurt images, very nice!
> I did:
> 
>  ./qemu-system-hexagon -M virt  -kernel ./qccdsp8380.mbn -nographic
> 
> and got something believable.
> 
>  Do you have glue that lets you run comms to the emulated qurt via
> fastrpc in the same way that, say a Llama running on a normal
> Linux host would?
>  It feels useful for debugging/watching what maths kernels are
> doing.

Hi,

There’s no FastRPC… however:

You can download the Hexagon SDK from https://softwarecenter.qualcomm.com/catalog/item/Hexagon_SDK

That comes with a version of QuRT that is semi-hosted as runelf.pbn.

A working QuRT loading on top of that (w/ a semi-hosted -M option):

-kernel /opt/Hexagon_SDK/6.7.0.0/rtos/qurt/computev75/sdksim_bin/runelf.pbn \
-append '/opt/Hexagon_SDK/6.7.0.0/libs/run_main_on_hexagon/ship/hexagon_toolv19_v75/run_main_on_hexagon_sim -- libmain.so'

The QEMU on Hexagon inside of the Hexagon also (used to) comes with an oddball QEMU Hexagon
version inside the package that has HMX emulation as a closed-source module, but that’s a
separate story that is going to be wound down thankfully.

If you don’t want to use the Hexagon SDK, there’s another option through hexagon-hypervisor which
has a very partial QuRT compat story. Or outright Linux on Hexagon which works too…

The (modern) kernel tree for Linux on Hexagon being at https://git.kernel.org/pub/scm/linux/kernel/git/bcain/linux.git/log/?h=hexagon

A pre-built artefact exists at https://artifacts.codelinaro.org/ui/native/codelinaro-toolchain-for-hexagon/23.1.2/qcs6490-cdsp/ with the booter at https://artifacts.codelinaro.org/ui/native/codelinaro-toolchain-for-hexagon/23.1.2/hexagon-hypervisor/

> 
>  (Not urgent, I'm just trying to get my head around it on my
> X1 laptop)
> 
>  Thanks in advance,
> 
> Dave
> -- 
> -----Open up your eyes, open up your mind, open up your code -------   
> / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
> \        dave @ treblig.org |                               | In Hex /
> \ _________________________|_____ http://www.treblig.org   |_______/
> 

Re: Qemu qurt and fastrpc?

[Brian Cain]

On 11/1/2026 5:41 PM, Mohamed Mediouni wrote:
>
>> On 1. Nov 2026, at 23:05, Dr. David Alan Gilbert <dave@treblig.org> wrote:
>>
>> Hi Brian,
>>   I tried your hexagon support booting qurt images, very nice!
>> I did:
>>
>>   ./qemu-system-hexagon -M virt  -kernel ./qccdsp8380.mbn -nographic
>>
>> and got something believable.
>>
>>   Do you have glue that lets you run comms to the emulated qurt via
>> fastrpc in the same way that, say a Llama running on a normal
>> Linux host would?
>>   It feels useful for debugging/watching what maths kernels are
>> doing.
> Hi,
>
> There’s no FastRPC… however:

Until we have heterogeneous TCG + ARM apps CPUs + SMMU + SMEM/cmd-db + 
DSP machine it's not likely to support FastRPC as-is.  This seems like 
it's quite a ways away, unfortunately. But we could conceivably craft 
something that resembles glink/fastrpc using ivshmem + doorbells.  That 
seems very do-able.

> You can download the Hexagon SDK from https://softwarecenter.qualcomm.com/catalog/item/Hexagon_SDK
>
> That comes with a version of QuRT that is semi-hosted as runelf.pbn.
>
> A working QuRT loading on top of that (w/ a semi-hosted -M option):
>
> -kernel /opt/Hexagon_SDK/6.7.0.0/rtos/qurt/computev75/sdksim_bin/runelf.pbn \
> -append '/opt/Hexagon_SDK/6.7.0.0/libs/run_main_on_hexagon/ship/hexagon_toolv19_v75/run_main_on_hexagon_sim -- libmain.so'

Indeed - sorry, should have some docs on how to do this coming Real Soon 
Now.  But that's the gist of it.


> The QEMU on Hexagon inside of the Hexagon also (used to) comes with an oddball QEMU Hexagon
> version inside the package that has HMX emulation as a closed-source module, but that’s a
> separate story that is going to be wound down thankfully.
>
> If you don’t want to use the Hexagon SDK, there’s another option through hexagon-hypervisor which
> has a very partial QuRT compat story. Or outright Linux on Hexagon which works too…
>
> The (modern) kernel tree for Linux on Hexagon being at https://git.kernel.org/pub/scm/linux/kernel/git/bcain/linux.git/log/?h=hexagon

Yeah, now that we have a decent basis in QEMU, I'll work on upstreaming 
those kernel changes.  Some have been reviewed on-list already.


> A pre-built artefact exists at https://artifacts.codelinaro.org/ui/native/codelinaro-toolchain-for-hexagon/23.1.2/qcs6490-cdsp/ with the booter at https://artifacts.codelinaro.org/ui/native/codelinaro-toolchain-for-hexagon/23.1.2/hexagon-hypervisor/

The h2 hypervisor is also available as a prebuilt rom in QEMU now, which 
is convenient for booting linux.  That h2 won't forward the 
QEMU-synthesized device tree pointer yet though :( - so it's probably 
easiest to build your kernel with its own internal DTB.


>>   (Not urgent, I'm just trying to get my head around it on my
>> X1 laptop)

If you want an X1 CDSP machine in QEMU - let me know.  We can include 
one in 12.0.  We did include the X2 CDSP - it's SC8480XP.


>>
>>   Thanks in advance,
>>
>> Dave
>> -- 
>> -----Open up your eyes, open up your mind, open up your code -------
>> / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \
>> \        dave @ treblig.org |                               | In Hex /
>> \ _________________________|_____ http://www.treblig.org   |_______/
>>

Re: Qemu qurt and fastrpc?

[Dr. David Alan Gilbert]

* Brian Cain (brian.cain@oss.qualcomm.com) wrote:

Hi Brian, Mohamed,
  Thanks for your replies.

> On 11/1/2026 5:41 PM, Mohamed Mediouni wrote:
> > 
> > > On 1. Nov 2026, at 23:05, Dr. David Alan Gilbert <dave@treblig.org> wrote:
> > > 
> > > Hi Brian,
> > >   I tried your hexagon support booting qurt images, very nice!
> > > I did:
> > > 
> > >   ./qemu-system-hexagon -M virt  -kernel ./qccdsp8380.mbn -nographic
> > > 
> > > and got something believable.
> > > 
> > >   Do you have glue that lets you run comms to the emulated qurt via
> > > fastrpc in the same way that, say a Llama running on a normal
> > > Linux host would?
> > >   It feels useful for debugging/watching what maths kernels are
> > > doing.
> > Hi,
> > 
> > There’s no FastRPC… however:
> 
> Until we have heterogeneous TCG + ARM apps CPUs + SMMU + SMEM/cmd-db + DSP
> machine it's not likely to support FastRPC as-is.  This seems like it's
> quite a ways away, unfortunately. But we could conceivably craft something
> that resembles glink/fastrpc using ivshmem + doorbells.  That seems very
> do-able.

Yeh it was that kind of hack I was wondering about; although just specifying
the Hexagon Qemu's guest memory as backed by a shared-memory file (like vhost-user)
would then let another process (i.e. the fastrpc library) read/modify the hexagon
ram.  So then the question is what doorbell-like things were needed.

My thoughts were something like a modified fastrpc library that spawned the qemu
(or connected to one), mmap'd the qemu's hexagon ram and then did...something to
do doorbell like things (e.g. maybe using qmp to read/write to the guest with
no change to the guest).
But no urgency etc, I might have a play.


> > You can download the Hexagon SDK from https://softwarecenter.qualcomm.com/catalog/item/Hexagon_SDK
> > 
> > That comes with a version of QuRT that is semi-hosted as runelf.pbn.
> > 
> > A working QuRT loading on top of that (w/ a semi-hosted -M option):
> > 
> > -kernel /opt/Hexagon_SDK/6.7.0.0/rtos/qurt/computev75/sdksim_bin/runelf.pbn \
> > -append '/opt/Hexagon_SDK/6.7.0.0/libs/run_main_on_hexagon/ship/hexagon_toolv19_v75/run_main_on_hexagon_sim -- libmain.so'
> 
> Indeed - sorry, should have some docs on how to do this coming Real Soon
> Now.  But that's the gist of it.

This one is a little less interesting from my side, I was more interested
in using the qemu as a way to see what was going on inside a running
fastrpc app.

> > The QEMU on Hexagon inside of the Hexagon also (used to) comes with an oddball QEMU Hexagon
> > version inside the package that has HMX emulation as a closed-source module, but that’s a
> > separate story that is going to be wound down thankfully.
> > 
> > If you don’t want to use the Hexagon SDK, there’s another option through hexagon-hypervisor which
> > has a very partial QuRT compat story. Or outright Linux on Hexagon which works too…
> > 
> > The (modern) kernel tree for Linux on Hexagon being at https://git.kernel.org/pub/scm/linux/kernel/git/bcain/linux.git/log/?h=hexagon
> 
> Yeah, now that we have a decent basis in QEMU, I'll work on upstreaming
> those kernel changes.  Some have been reviewed on-list already.
> 
> 
> > A pre-built artefact exists at https://artifacts.codelinaro.org/ui/native/codelinaro-toolchain-for-hexagon/23.1.2/qcs6490-cdsp/ with the booter at https://artifacts.codelinaro.org/ui/native/codelinaro-toolchain-for-hexagon/23.1.2/hexagon-hypervisor/
> 
> The h2 hypervisor is also available as a prebuilt rom in QEMU now, which is
> convenient for booting linux.  That h2 won't forward the QEMU-synthesized
> device tree pointer yet though :( - so it's probably easiest to build your
> kernel with its own internal DTB.
> 
> 
> > >   (Not urgent, I'm just trying to get my head around it on my
> > > X1 laptop)
> 
> If you want an X1 CDSP machine in QEMU - let me know.  We can include one in
> 12.0.  We did include the X2 CDSP - it's SC8480XP.

For me that would probably be useful only with the hack mentioned at the top
to allow a fastrpc use; but given the number of X1's out there it's probably
not a bad idea.

Thanks again.

Dave

> 
> > > 
> > >   Thanks in advance,
> > > 
> > > Dave
> > > -- 
> > > -----Open up your eyes, open up your mind, open up your code -------
> > > / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \
> > > \        dave @ treblig.org |                               | In Hex /
> > > \ _________________________|_____ http://www.treblig.org   |_______/
> > > 
-- 
 -----Open up your eyes, open up your mind, open up your code -------   
/ Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
\        dave @ treblig.org |                               | In Hex /
 \ _________________________|_____ http://www.treblig.org   |_______/