* Vitaly Kuznetsov (vkuzn...@redhat.com) wrote: > Philippe Mathieu-Daudé <phi...@redhat.com> writes: > > > +Vitaly > > > > On 7/23/20 10:40 AM, Dr. David Alan Gilbert wrote: > >> * 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. > >> > > (sorry, missed the beginning of the discussion) > > So one does: > > (qemu) system_reset > > on Intel wiht '-cpu host' and the result is: > > (qemu) KVM: entry failed, hardware error 0x80000021
Interesting; I hadn't seen that error - I just see a hard hung guest rather than a reset one. (i7-8650U laptop 5.7.9 fedora 32) Dave > If you're running a guest on an Intel machine without unrestricted mode > support, the failure can be most likely due to the guest entering an invalid > state for Intel VT. For example, the guest maybe running in big real mode > which is not supported on less recent Intel processors. > > EAX=00000064 EBX=91df5efe ECX=00000000 EDX=000003f8 > ESI=00000000 EDI=91ee32c0 EBP=90643260 ESP=00013c68 > EIP=906428e6 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0 > ES =0000 00000000 0000ffff 00009300 > CS =f000 ffff0000 0000ffff 00009b00 > SS =0000 00000000 0000ffff 00009300 > DS =0000 00000000 0000ffff 00009300 > FS =0000 00000000 0000ffff 00009300 > GS =0000 00000000 0000ffff 00009300 > LDT=0000 00000000 0000ffff 00008200 > TR =0000 00000000 0000ffff 00008b00 > GDT= 00000000 0000ffff > IDT= 00000000 0000ffff > CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000 > DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 > DR3=0000000000000000 > DR6=00000000ffff0ff0 DR7=0000000000000400 > EFER=0000000000000000 > Code=?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? <??> ?? ?? > ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? > ?? > > I can take a look (if no one beats me to it). > > -- > Vitaly > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
