Messages in this thread | | | Date | Tue, 28 Jun 2022 09:35:28 +0700 | Subject | Re: [PATCH v6 15/17] KVM: SVM: Use target APIC ID to complete x2AVIC IRQs when possible | From | "Suthikulpanit, Suravee" <> |
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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.
Best Regards, Suravee
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