On Tue, Sep 05, 2023, Peter Gonda wrote: > Currently if an SEV-ES VM shuts down userspace sees KVM_RUN struct with > only the INVALID_ARGUMENT. This is a very limited amount of information > to debug the situation. Instead KVM can return a > KVM_SYSTEM_EVENT_SEV_TERM to alert userspace the VM is shutting down and > is not usable any further. This latter point can be enforced using the > kvm_vm_dead() functionality. Add the kvm_vm_dead() thing in a separate patch. If we want to actually harden KVM against consuming a garbage VMSA then we do need to mark the VM dead, but on the other hand that will block _all_ KVM ioctls(), which will make debug even harder. > Signed-off-by: Peter Gonda <pgonda@xxxxxxxxxx> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Sean Christopherson <seanjc@xxxxxxxxxx> > Cc: Tom Lendacky <thomas.lendacky@xxxxxxx> > Cc: Joerg Roedel <joro@xxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxxxx> > Cc: x86@xxxxxxxxxx > Cc: kvm@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > > --- > > I am not sure if this is the right path forward maybe just returning > KVM_EXIT_SHUTDOWN is better. But the current behavior is very unhelpful. Ya, KVM_EXIT_SHUTDOWN is better, we should leave KVM_SYSTEM_EVENT_SEV_TERM to explicit "requests" from the guest.
