On Wed, Jun 12, 2019 at 09:51:52PM +0200, Borislav Petkov wrote: > On Wed, Jun 12, 2019 at 02:45:34PM -0400, George Kennedy wrote: > > The crash can still be reproduced with VM running Upstream 5.2.0-rc4 > > That's clear. > > > and host running Ubuntu on AMD CPU. > > That's the important question: why can't I trigger it with 5.2.0-rc4+ as > the host and you can with the ubuntu kernel 4.15 or so. I.e., what changed > upstream or does the ubuntu kernel have out-of-tree stuff? > > Maybe kvm folks would have a better idea. That kvm_spurious_fault thing > is for: > > /* > * Hardware virtualization extension instructions may fault if a > * reboot turns off virtualization while processes are running. > * Trap the fault and ignore the instruction if that happens. > */ > asmlinkage void kvm_spurious_fault(void); > > but you're not rebooting... The reboot thing is a red-herring. The ____kvm_handle_fault_on_reboot() macro suppresses faults that occur on VMX and SVM instructions while the kernel is rebooting (CPUs need to leave VMX/SVM mode to recognize INIT), i.e. kvm_spurious_fault() is reached when a VMX or SVM instruction faults and we're *not* rebooting. TL;DR: an SVM instruction is faulting unexpectedly.
