Re: [RFC PATCH V5 15/15] x86/sev: Fix interrupt exit code paths from #HV exception

Tianyu Lan
2023-05-04T22:41:32Z

On 5/1/2023 9:02 AM, Tom Lendacky wrote:
>> From: Ashish Kalra <ashish.kalra@amd.com>
>>
>> Add checks in interrupt exit code paths in case of returns
>> to user mode to check if currently executing the #HV handler
>> then don't follow the irqentry_exit_to_user_mode path as
>> that can potentially cause the #HV handler to be
>> preempted and rescheduled on another CPU. Rescheduled #HV
>> handler on another cpu will cause interrupts to be handled
>> on a different cpu than the injected one, causing
>> invalid EOIs and missed/lost guest interrupts and
>> corresponding hangs and/or per-cpu IRQs handled on
>> non-intended cpu.
>>
>> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
>
> This should be merged into one of the appropriate #HV patches and just
> add Ashish with a Co-developed-by: tag where appropriate. This would be
> appropriate as a separate only if discovered after the series was merged.

Sure. Will update in the next version.