On Wed, Jul 15, 2020 at 07:45:13PM +0200, Igor Mammedov wrote: > While testing ACPI cpu hotplug changes I stumbled on BSOD in case > QEMU is configured with 256 CPUs, Windows Server 2012R2x64 fails to boot > with bugcheck 5C > > > qemu-system-x86_64 -m 4G -smp 2,sockets=64,cores=4,maxcpus=256 -M > q35,kernel-irqchip=split -enable-kvm -device intel-iommu,intremap=on,eim=on > ws2012r2x64DCchk.qcow2 > > Looking at stacktrace, it seems that is fails when trying to initialize iommu > > hal_interrupt_remapping_setup_failure_nt!initbootprocessor > > Any idea what to try to figure out what QEMU is missing wrt intremap? > > PS: > WS2016 boots eventually, but CPU hotplug doesn't work, symptoms (unconfirmed > yet) like SCI isn't being delivered. > With RHEL76 the same config works fine.
Igor, Could you try this again but with vtd tracepoints enabled? -trace enable="vtd_*" I think we don't need to capture all the trace outputs, but only until when the HAL error message triggered should work. Thanks, -- Peter Xu
