[edk2-devel] [edk2-staging/RiscV64QemuVirt PATCH V7 05/20] UefiCpuPkg: Add CpuTimerDxe module
Michael Brown
mcb30 at ipxe.org
Thu Feb 9 10:30:58 UTC 2023
On 09/02/2023 10:28, Sunil V L wrote:
>>> + gBS->RestoreTPL (OriginalTPL);
>>> + RiscVEnableTimerInterrupt (); // enable SMode timer int
>>> +}
>>
>> This design looks as though it does not support nested timer interrupts.
>> The call to RestoreTPL() may invoke callbacks that may themselves include
>> delay loops that wait upon further timer interrupts. With the above code,
>> those timer interrupts will never arrive since the timer interrupt is
>> disabled at the point that you call RestoreTPL().
>>
>> This will break device drivers such as those for USB network devices that
>> rely on nested timer interrupts.
>
> Thanks a lot for this feedback and background. We are aware of few issues
> in this module. Currently, it is mostly porting what exists today in
> edk2-platforms repo. We want to add all these additional fixes after
> this basic thing is merged. That way we will have git history instead of
> combining all fixes single commit. Andrei has a patch ready and waiting
> for this to get merged. We can either combine this with his patch or
> create one more.
>
> Would that strategy be fine with you?
Sure, as long as someone other than me is keeping track of the need to
fix this bug. My work here is done. :)
Thanks,
Michael
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