[SRU Justification] [Impact]
Current linux-azure-4.15 kernel in bionic fails to boot Standard_M416s_v2 VM because of x2apic being disabled: [ 0.000000] x2apic: IRQ remapping doesn't support X2APIC mode [ 0.000000] unchecked MSR access error: WRMSR to 0x1b (tried to write 0x00000000fee00100) at rIP: 0xffffffff9325d1f8 (native_write_msr+0x8/0x30) [ 0.000000] Call Trace: [ 0.000000] __x2apic_disable.part.5+0x49/0x80 [ 0.000000] enable_IR_x2apic+0x123/0x18c [ 0.000000] default_setup_apic_routing+0x16/0x73 [ 0.000000] apic_intr_mode_init+0x84/0x91 [ 0.000000] x86_late_time_init+0x24/0x2b [ 0.000000] start_kernel+0x444/0x505 [ 0.000000] x86_64_start_reservations+0x24/0x26 [ 0.000000] x86_64_start_kernel+0x74/0x77 [ 0.000000] secondary_startup_64+0xa5/0xb0 [ 0.000000] x2apic disabled [ 0.000000] Switched APIC routing to physical flat. [Test Plan] Run updated kernel (with x2apic support backported from linux-azure-5.4 kernel). It should boot fine and display: [ 0.000000] Setting APIC routing to physical x2apic. [Where problems could occur] Potentially x2apic may now be used on other VM instances. [Other Info] None. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1951924 Title: linux-azure 4.15 fails to boot on Standard_M416s_v2 in Azure To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1951924/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
