Fix is in master: https://github.com/qemu/qemu/commit/e0dd5fd41a1a38766009f442967fab700d2d0550
** Changed in: qemu Status: In Progress => Fix Committed -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1719984 Title: wrgsbase misemulated in x86_64-softmmu Status in QEMU: Fix Committed Bug description: qemu revision: cfe4cade054c0e0d00d0185cdc433a9e3ce3e2e4 command: ./qemu-system-x86_64 -m 2048 -nographic -net none -smp 4,threads=2 -machine q35 -kernel zircon.bin -cpu Haswell,+smap,-check -initrd bootdata.bin -append 'TERM=screen kernel.halt-on-panic=true ' On this revision, the VM reports CPUID.07H.0H.EBX[0] = 1. In this VM, with CR4[16] set to 1, wrgsbase triggers #UD, which mismatches the behavior described in Intel's instruction reference. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1719984/+subscriptions