On Tue, Jan 19, 2021 at 09:45:19AM +0100, Stefano Garzarella wrote: > On Mon, Jan 18, 2021 at 04:03:12PM +0000, Dr. David Alan Gilbert wrote: > > * Stefano Garzarella (sgarz...@redhat.com) wrote: > > > Commit 9d7bd0826f introduced a new 'use-disabled-flag' property > > > set to true by default. > > > To allow the migration, we set this property to false in the hw_compat, > > > but in the wrong place (hw_compat_4_1). > > > > > > Since commit 9d7bd0826f was released with QEMU 5.0, we move > > > 'use-disabled-flag' property to hw_compat_4_2, so 4.2 machine types > > > will have the pre-patch behavior and the migration can work. > > > > Be a little careful that fixing this probably causes a migration from > > 5.2->6.0 to fail with this machine type; so when we do these > > type of fixes we often fix an old machine type between some pair of qemu > > versions and then break it between a different set. > > Good point! > > I did some tests using the example below always using pc-q35-4.2 and it > seems that works well: > > - 5.2 -> 6.0 pass > - 5.2 -> 4.2 FAIL > - 6.0 -> 5.2 pass > - 6.0 -> 4.2 pass > - 4.2 -> 5.2 pass > - 4.2 -> 6.0 pass > > Should I run some more tests? > > Thanks, > Stefano
dgilbert how about an ack? > > > > Dave > > > > > The issue was discovered with vhost-vsock device and 4.2 machine > > > type without running any kernel in the VM: > > > $ qemu-4.2 -M pc-q35-4.2,accel=kvm \ > > > -device vhost-vsock-pci,guest-cid=4 \ > > > -monitor stdio -incoming tcp:0:3333 > > > > > > $ qemu-5.2 -M pc-q35-4.2,accel=kvm \ > > > -device vhost-vsock-pci,guest-cid=3 \ > > > -monitor stdio > > > (qemu) migrate -d tcp:0:3333 > > > > > > # qemu-4.2 output > > > qemu-system-x86_64: Failed to load virtio-vhost_vsock:virtio > > > qemu-system-x86_64: error while loading state for instance 0x0 of > > > device '0000:00:03.0/virtio-vhost_vsock' > > > qemu-system-x86_64: load of migration failed: No such file or > > > directory > > > > > > Reported-by: Jing Zhao <jinz...@redhat.com> > > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1907255 > > > Fixes: 9d7bd0826f ("virtio-pci: disable vring processing when > > > bus-mastering is disabled") > > > Cc: mdr...@linux.vnet.ibm.com > > > CC: qemu-sta...@nongnu.org > > > Signed-off-by: Stefano Garzarella <sgarz...@redhat.com> > > > --- > > > hw/core/machine.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/hw/core/machine.c b/hw/core/machine.c > > > index de3b8f1b31..5d6163ab70 100644 > > > --- a/hw/core/machine.c > > > +++ b/hw/core/machine.c > > > @@ -70,12 +70,12 @@ GlobalProperty hw_compat_4_2[] = { > > > { "qxl", "revision", "4" }, > > > { "qxl-vga", "revision", "4" }, > > > { "fw_cfg", "acpi-mr-restore", "false" }, > > > + { "virtio-device", "use-disabled-flag", "false" }, > > > }; > > > const size_t hw_compat_4_2_len = G_N_ELEMENTS(hw_compat_4_2); > > > > > > GlobalProperty hw_compat_4_1[] = { > > > { "virtio-pci", "x-pcie-flr-init", "off" }, > > > - { "virtio-device", "use-disabled-flag", "false" }, > > > }; > > > const size_t hw_compat_4_1_len = G_N_ELEMENTS(hw_compat_4_1); > > > > > > -- > > > 2.26.2 > > > > > -- > > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > >
