[Xen-devel] [PATCH]Fixes for overflowed calculation in vHPET

["Shan, Haitao" <haitao.shan@xxxxxxxxx>]

This patch will fix the bugs in hpet_set_timer. Currently in hpet_tick_to_ns, the approach is multiplying first, which easily causes overflow when tick is quite large. The patch cannot handle arbitrate large ticks duo to the precision requirement and 64bit's value range. But by optimize the equation, a larger ticks than current code can be supported. Also an overflow check is added before the calculation.

This patch will also fix the wrong handling of wrap around case when timer is in 64bit mode.

Best Regards
Haitao Shan

Attachment: hpet2.patch
Description: hpet2.patch

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