On 1/15/24 19:10, Kinney, Michael D wrote: > Hi Ray, > > I think nesting may be possible in physical platforms, but very hard > to induce. > > One option is to consolidate to a single LocalApicTimerDxe > implementation in the UefiCpuPkg, but allow the platform DSC to either > specify a Null NestedInterruptTplLib for physical platforms or the > full one from the OvmfPkg for VM use cases. > > The other changes could be included for OvmfPkg use cases. If the VM > does not support the CPUID leafs, then the PCD value should be used.
All of this sounds great! (And I do think that *some* nesting should not be a problem, on either physical or virtual platforms, as (IIRC) the interrupt handler stack can accommodate a certain level of reentrancy. It's the "storm" that is a problem, but that should never occur on physical machines, I reckon.) Assuming a v2 is coming up, my advance request would be for Ray to re-review the math in patch #4, before posting v2, focusing on integer overflows, and SafeIntLib (if needed). I've not looked at the patch in detail yet, but I reviewed something similar not so long ago [1]. The latter frequency calculation code had been quite commonly used in edk2, and I needed hours to review just that one patch. Plus, the review turned up a number of issues to fix. So, preferably such a patch should not only prevent any integer overflows, but also clarify, in comments, why overflows are impossible, and/or how they are prevented. [1] https://edk2.groups.io/g/devel/message/111613 2e42db7c-a927-f47b-7d80-632895b11e1b@redhat.com">http://mid.mail-archive.com/2e42db7c-a927-f47b-7d80-632895b11e1b@redhat.com Thanks! Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#113884): https://edk2.groups.io/g/devel/message/113884 Mute This Topic: https://groups.io/mt/103734961/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
