Hi Juergen,
On 08/02/2021 10:22, Jürgen Groß wrote:
On 08.02.21 10:54, Julien Grall wrote:
... I don't really see how the difference matter here. The idea is to re-use what's already existing rather than trying to re-invent the wheel with an extra lock (or whatever we can come up).
The difference is that the race is occurring _before_ any IRQ is involved. So I don't see how modification of IRQ handling would help.
Roughly our current IRQ handling flow (handle_eoi_irq()) looks like:
if ( irq in progress ) { set IRQS_PENDING return; }
do { clear IRQS_PENDING handle_irq() } while (IRQS_PENDING is set)
IRQ handling flow like handle_fasteoi_irq() looks like:
if ( irq in progress ) return;
handle_irq()
The latter flow would catch "spurious" interrupt and ignore them. So it would handle nicely the race when changing the event affinity.
Cheers,