On 11/10/2024 5:42 PM, Borislav Petkov wrote: > On Sun, Nov 10, 2024 at 09:25:34AM +0530, Neeraj Upadhyay wrote: >> Given that in step 3, hv uses "apic_id" (provided by guest) to find the >> corresponding vCPU information, "apic_id" and "hv_apic_id" need to match. >> Mismatch is not considered as a fatal event for guest (snp_abort() is not >> triggered) and a warning is raise, > > What is it considered then and why does the warning even exist? > APIC ID mismatch can delay IPI handling, which can result in slow guest by delaying activities like scheduling of tasks within guest. > What can anyone do about it? > The misconfiguration would require fixing the vCPUs' APIC ID in the host. > If you don't kill the guest, what should the guest owner do if she sees that > warning? > If I get your point, unless a corrective action is possible without hard reboot of the guest, doing a snp_abort() on detecting mismatch works better here. That way, the issue can be caught early, and it does not disrupt the running applications on a limping guest (which happens for the case where we only emit a warning). So, thinking more, snp_abort() looks more apt here. - Neeraj
