Re: [Qemu-devel] [PATCH 1/3] migration: Add a new option to enable only-migratable

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Ashijeet Acharya (ashijeetacharya@gmail.com) wrote:
> On Thu, Dec 15, 2016 at 8:59 PM, Dr. David Alan Gilbert
> <dgilbert@redhat.com> wrote:
> > * Ashijeet Acharya (ashijeetacharya@gmail.com) wrote:
> >> Add a new option "--only-migratable" in qemu which will allow to add
> >> only those devices which will not fail qemu after migration. Devices
> >> set with the flag 'unmigratable' cannot be added when this option will
> >> be used.
> >>
> >> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
> >> ---
> >>  include/migration/migration.h |  3 +++
> >>  qemu-options.hx               | 10 ++++++++++
> >>  vl.c                          |  4 ++++
> >>  3 files changed, 17 insertions(+)
> >>
> >> diff --git a/include/migration/migration.h b/include/migration/migration.h
> >> index c309d23..40b3697 100644
> >> --- a/include/migration/migration.h
> >> +++ b/include/migration/migration.h
> >> @@ -38,6 +38,9 @@
> >>  #define QEMU_VM_COMMAND              0x08
> >>  #define QEMU_VM_SECTION_FOOTER       0x7e
> >>
> >> +/* for vl.c */
> >> +extern int only_migratable;
> >> +
> >>  struct MigrationParams {
> >>      bool blk;
> >>      bool shared;
> >> diff --git a/qemu-options.hx b/qemu-options.hx
> >> index c534a2f..7cc2cc5 100644
> >> --- a/qemu-options.hx
> >> +++ b/qemu-options.hx
> >> @@ -3574,6 +3574,16 @@ be used to change settings (such as migration parameters) prior to issuing
> >>  the migrate_incoming to allow the migration to begin.
> >>  ETEXI
> >>
> >> +DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
> >> +    "-only-migratable     allow only migratable devices\n", QEMU_ARCH_ALL)
> >> +STEXI
> >> +@item -only-migratable
> >> +@findex -only-migratable
> >> +Don't allow adding devices that will fail QEMU after migration. Devices set with
> >> +the flag unmigratable are not allowed to be added neither statically nor
> >> +dynamically
> >> +ETEXI
> >
> > Can I suggest rewording that as:
> > Only allow migratable devices.  Devices will not be allowed to enter an unmigratable
> > state.
> 
> No problem, will fix that in v2.
> 
> >>  DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
> >>      "-nodefaults     don't create default devices\n", QEMU_ARCH_ALL)
> >>  STEXI
> >> diff --git a/vl.c b/vl.c
> >> index d77dd86..82bffb9 100644
> >> --- a/vl.c
> >> +++ b/vl.c
> >> @@ -180,6 +180,7 @@ bool boot_strict;
> >>  uint8_t *boot_splash_filedata;
> >>  size_t boot_splash_filedata_size;
> >>  uint8_t qemu_extra_params_fw[2];
> >> +int only_migratable = 0; /* turn it off unless user states otherwise */
> >>
> >>  int icount_align_option;
> >>
> >> @@ -3914,6 +3915,9 @@ int main(int argc, char **argv, char **envp)
> >>                  }
> >>                  incoming = optarg;
> >>                  break;
> >> +            case QEMU_OPTION_only_migratable:
> >> +                only_migratable = 1;
> >> +                break;
> >>              case QEMU_OPTION_nodefaults:
> >>                  has_defaults = 0;
> >>                  break;
> >
> > Does this need to go in the 'first pass of option parsing' loop
> > to make sure that it doesn't matter which order it's in and it
> > stops other devices on the command line?
> 
> I am not sure what you meant by order here;
> 
> Do you mean the order as in the place --only-migratable is used,
> 
> 1. ./bin/qemu-system-x86_64 -m 1024 -name f15 -device
> nec-usb-xhci,id=xhci -device usb-uas,id=uas,bus=xhci.0
> --only-migratable
> 2. ./bin/qemu-system-x86_64 -m 1024 -name f15 --only-migratable
> -device nec-usb-xhci,id=xhci -device usb-uas,id=uas,bus=xhci.0
> 
> Because I have tested both and they seem to be working equally fine.
> Sorry if I understood wrong.

If that works OK that's fine, no change needed.

Dave

> 
> Ashijeet
> 
> > Dave
> >
> >> --
> >> 2.6.2
> >>
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK