* Eduardo Habkost (ehabk...@redhat.com) wrote: > On Wed, Jul 22, 2020 at 04:47:32PM -0400, Eduardo Habkost wrote: > > On Wed, Jul 22, 2020 at 08:05:01PM +0200, Jan Kiszka wrote: > > > On 22.07.20 19:35, Eduardo Habkost wrote: > > > > Hi Jan, > > > > > > > > What was the last version where it worked for you? Does using > > > > "-cpu host,-vmx" help? > > > > > > Yeah, -vmx does indeed help. > > > > > > I didn't have the time to bisect yet. Just check my reflog, picked > > > eb6490f544, and that works. > > > > Thanks! > > > > I could reproduce it locally[1], I will bisect it. > > > > The good news is that "-cpu host,+vmx" still works, on commit > > eb6490f544. > > > > [1] Linux 5.6.19-300.fc32.x86_64, Intel Core i7-8665U CPU. > > Bisected to: > > commit b16c0e20c74218f2d69710cedad11da7dd4d2190 > Author: Paolo Bonzini <pbonz...@redhat.com> > Date: Wed May 20 10:49:22 2020 -0400 > > KVM: add support for AMD nested live migration > > Support for nested guest live migration is part of Linux 5.8, add the > corresponding code to QEMU. The migration format consists of a few > flags, is an opaque 4k blob. > > The blob is in VMCB format (the control area represents the L1 VMCB > control fields, the save area represents the pre-vmentry state; KVM does > not use the host save area since the AMD manual allows that) but QEMU > does not really care about that. However, the flags need to be > copied to hflags/hflags2 and back. > > In addition, support for retrieving and setting the AMD nested > virtualization > states allows the L1 guest to be reset while running a nested guest, but > a small bug in CPU reset needs to be fixed for that to work. > > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Guesswork led me to try reverting the chunk in kvm_put_nested_state; without it the reset seems to work; I can't explain that code though. Dave > > -- > Eduardo > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK