Re: [PATCH v11 05/10] arm/hvf: Add a WFI handler

[Alexander Graf]

On 16.09.21 06:49, Philippe Mathieu-Daudé wrote:
> On 9/15/21 8:10 PM, Alexander Graf wrote:
>> From: Peter Collingbourne <pcc@google.com>
>>
>> Sleep on WFI until the VTIMER is due but allow ourselves to be woken
>> up on IPI.
>>
>> In this implementation IPI is blocked on the CPU thread at startup and
>> pselect() is used to atomically unblock the signal and begin sleeping.
>> The signal is sent unconditionally so there's no need to worry about
>> races between actually sleeping and the "we think we're sleeping"
>> state. It may lead to an extra wakeup but that's better than missing
>> it entirely.
>>
>> Signed-off-by: Peter Collingbourne <pcc@google.com>
>> [agraf: Remove unused 'set' variable, always advance PC on WFX trap,
>>         support vm stop / continue operations and cntv offsets]
>> Signed-off-by: Alexander Graf <agraf@csgraf.de>
>> Acked-by: Roman Bolshakov <r.bolshakov@yadro.com>
>> Reviewed-by: Sergio Lopez <slp@redhat.com>
>>
>> ---
>> diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
>> index 8fe008dab5..49f265cc08 100644
>> --- a/target/arm/hvf/hvf.c
>> +++ b/target/arm/hvf/hvf.c
>> @@ -2,6 +2,7 @@
>>   * QEMU Hypervisor.framework support for Apple Silicon
>>  
>>   * Copyright 2020 Alexander Graf <agraf@csgraf.de>
>> + * Copyright 2020 Google LLC
>>   *
>>   * This work is licensed under the terms of the GNU GPL, version 2 or later.
>>   * See the COPYING file in the top-level directory.
>> @@ -490,6 +491,7 @@ int hvf_arch_init_vcpu(CPUState *cpu)
>>  
>>  void hvf_kick_vcpu_thread(CPUState *cpu)
>>  {
>> +    cpus_kick_thread(cpu);
> Doesn't this belong to the previous patch?


Until this patch, we're never running outside guest context on the vCPU
thread, so hv_vcpus_exit() is enough to kick us out :).


Thanks a lot for the review!

Alex