Hello,

The Processor Control facility for POWER8 processors and later
provides a mechanism for the hypervisor to send messages to other
threads in the system (msgsnd instruction) and cause hypervisor-level
exceptions.

Privileged non-hypervisor programs can also send messages (msgsndp
instruction) but are restricted to the threads of the same
subprocessor and cause privileged-level exceptions. The Directed
Privileged Doorbell Exception State (DPDES) register reflects the
state of pending privileged-level doorbell exceptions for all threads
and can be used to modify that state.

If the MSGP facility is not in the HFSCR, a hypervisor facility
unavailable exception is generated when these instructions are used or
when the DPDES register is accessed by the supervisor.

Based on previous work from Suraj Jitindar Singh. 

Thanks,

C.

Changes since v1:

 - removed DBELL_TIRTAG_MASK and simplified helpers as QEMU TCG
   doesn't support more than on thread per core   
 - simplified book3s_dbell2irq() and renamed it to dbell_type_server() 
 - replaced mask LOG_GUEST_ERROR by CPU_LOG_INT to track HV Facility
   errors
 
Cédric Le Goater (2):
  target/ppc: Add privileged message send facilities
  target/ppc: add support for Hypervisor Facility Unavailable Exception

 target/ppc/cpu.h                |  6 +++
 target/ppc/helper.h             |  4 ++
 target/ppc/excp_helper.c        | 79 ++++++++++++++++++++++++++-------
 target/ppc/misc_helper.c        | 63 ++++++++++++++++++++++++++
 target/ppc/translate.c          | 26 +++++++++++
 target/ppc/translate_init.inc.c | 20 +++++++--
 6 files changed, 178 insertions(+), 20 deletions(-)

-- 
2.21.1

On Mon, Jan 20, 2020 at 11:49:33AM +0100, Cédric Le Goater wrote:
> Hello,
> 
> The Processor Control facility for POWER8 processors and later
> provides a mechanism for the hypervisor to send messages to other
> threads in the system (msgsnd instruction) and cause hypervisor-level
> exceptions.
> 
> Privileged non-hypervisor programs can also send messages (msgsndp
> instruction) but are restricted to the threads of the same
> subprocessor and cause privileged-level exceptions. The Directed
> Privileged Doorbell Exception State (DPDES) register reflects the
> state of pending privileged-level doorbell exceptions for all threads
> and can be used to modify that state.
> 
> If the MSGP facility is not in the HFSCR, a hypervisor facility
> unavailable exception is generated when these instructions are used or
> when the DPDES register is accessed by the supervisor.
> 
> Based on previous work from Suraj Jitindar Singh.

Applied to ppc-for-5.0, thanks.

> 
> Thanks,
> 
> C.
> 
> Changes since v1:
> 
>  - removed DBELL_TIRTAG_MASK and simplified helpers as QEMU TCG
>    doesn't support more than on thread per core   
>  - simplified book3s_dbell2irq() and renamed it to dbell_type_server() 
>  - replaced mask LOG_GUEST_ERROR by CPU_LOG_INT to track HV Facility
>    errors
>  
> Cédric Le Goater (2):
>   target/ppc: Add privileged message send facilities
>   target/ppc: add support for Hypervisor Facility Unavailable Exception
> 
>  target/ppc/cpu.h                |  6 +++
>  target/ppc/helper.h             |  4 ++
>  target/ppc/excp_helper.c        | 79 ++++++++++++++++++++++++++-------
>  target/ppc/misc_helper.c        | 63 ++++++++++++++++++++++++++
>  target/ppc/translate.c          | 26 +++++++++++
>  target/ppc/translate_init.inc.c | 20 +++++++--
>  6 files changed, 178 insertions(+), 20 deletions(-)
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson