On Tue, 2022-06-28 at 09:35 +0700, Suthikulpanit, Suravee wrote: > > On 6/28/2022 5:55 AM, Maxim Levitsky wrote: > > On Fri, 2022-06-24 at 18:41 +0200, Paolo Bonzini wrote: > > > On 5/19/22 12:27, Suravee Suthikulpanit wrote: > > > > + * If the x2APIC logical ID sub-field (i.e. icrh[15:0]) contains zero > > > > + * or more than 1 bits, we cannot match just one vcpu to kick for > > > > + * fast path. > > > > + */ > > > > + if (!first || (first != last)) > > > > + return -EINVAL; > > > > + > > > > + apic = first - 1; > > > > + if ((apic < 0) || (apic > 15) || (cluster >= 0xfffff)) > > > > + return -EINVAL; > > > > > > Neither of these is possible: first == 0 has been cheked above, and > > > ffs(icrh & 0xffff) cannot exceed 15. Likewise, cluster is actually > > > limited to 16 bits, not 20. > > > > > > Plus, C is not Pascal so no parentheses. :) > > > > > > Putting everything together, it can be simplified to this: > > > > > > + int cluster = (icrh & 0xffff0000) >> 16; > > > + int apic = ffs(icrh & 0xffff) - 1; > > > + > > > + /* > > > + * If the x2APIC logical ID sub-field (i.e. icrh[15:0]) > > > + * contains anything but a single bit, we cannot use the > > > + * fast path, because it is limited to a single vCPU. > > > + */ > > > + if (apic < 0 || icrh != (1 << apic)) > > > + return -EINVAL; > > > + > > > + l1_physical_id = (cluster << 4) + apic; > > > > > > > > > > + apic_id = (cluster << 4) + apic; > > > > Hi Paolo and Suravee Suthikulpanit! > > > > Note that this patch is not needed anymore, I fixed the avic_kick_target_vcpus_fast function, > > and added the support for x2apic because it was very easy to do > > (I already needed to parse logical id for flat and cluser modes) > > > > Best regards, > > Maxim Levitsky > > > > Understood. I was about to send v7 to remove this patch from the series, but too late. I'll test the current queue branch and provide update. Also this really needs a KVM unit test, to avoid breaking corner cases like sending IPI to 0xFF address, which was the reason I had to fix the avic_kick_target_vcpus_fast. We do have 'apic' test in kvm unit tests, and I was already looking to extend it to cover more cases and to run it with AVIC's compatible settings. I hope I will be able to do this this week. Best regards, Maxim Levitsky > > Best Regards, > Suravee >
