Re: [Qemu-devel] [PATCH v4 32/47] postcopy: ram_enable_notify to switch on userfault

[David Gibson]

On Wed, Nov 19, 2014 at 06:59:38PM +0000, Dr. David Alan Gilbert wrote:
> * David Gibson (address@hidden) wrote:
> > On Fri, Oct 03, 2014 at 06:47:38PM +0100, Dr. David Alan Gilbert (git) 
> > wrote:
> > > From: "Dr. David Alan Gilbert" <address@hidden>
> > > 
> > > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > > ---
> > >  include/migration/migration.h    |  2 ++
> > >  include/migration/postcopy-ram.h |  6 +++++
> > >  postcopy-ram.c                   | 49 
> > > +++++++++++++++++++++++++++++++++++++++-
> > >  savevm.c                         |  9 ++++++++
> > >  4 files changed, 65 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > > index be63c89..b01cc17 100644
> > > --- a/include/migration/migration.h
> > > +++ b/include/migration/migration.h
> > > @@ -87,6 +87,8 @@ struct MigrationIncomingState {
> > >          POSTCOPY_RAM_INCOMING_END
> > >      } postcopy_ram_state;
> > >  
> > > +    /* For the kernel to send us notifications */
> > > +    int            userfault_fd;
> > >      QEMUFile *return_path;
> > >      QemuMutex      rp_mutex;    /* We send replies from multiple threads 
> > > */
> > >      PostcopyPMI    postcopy_pmi;
> > > diff --git a/include/migration/postcopy-ram.h 
> > > b/include/migration/postcopy-ram.h
> > > index 8f237a2..413b670 100644
> > > --- a/include/migration/postcopy-ram.h
> > > +++ b/include/migration/postcopy-ram.h
> > > @@ -19,6 +19,12 @@
> > >  int postcopy_ram_hosttest(void);
> > >  
> > >  /*
> > > + * Make all of RAM sensitive to accesses to areas that haven't yet been 
> > > written
> > > + * and wire up anything necessary to deal with it.
> > > + */
> > > +int postcopy_ram_enable_notify(MigrationIncomingState *mis);
> > > +
> > > +/*
> > >   * Initialise postcopy-ram, setting the RAM to a state where we can go 
> > > into
> > >   * postcopy later; must be called prior to any precopy.
> > >   * called from arch_init's similarly named ram_postcopy_incoming_init
> > > diff --git a/postcopy-ram.c b/postcopy-ram.c
> > > index 8eccf26..925ac77 100644
> > > --- a/postcopy-ram.c
> > > +++ b/postcopy-ram.c
> > > @@ -485,9 +485,51 @@ int 
> > > postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
> > >      return 0;
> > >  }
> > >  
> > > +/*
> > > + * Mark the given area of RAM as requiring notification to unwritten 
> > > areas
> > > + * Used as a  callback on qemu_ram_foreach_block.
> > > + *   host_addr: Base of area to mark
> > > + *   offset: Offset in the whole ram arena
> > > + *   length: Length of the section
> > > + *   opaque: Unused
> > 
> >                 ^^^^^^
> > This appears to be wrong - opaque is used to find the MIS.
> 
> Fixed.
> 
> > 
> > > + * Returns 0 on success
> > > + */
> > > +static int postcopy_ram_sensitise_area(const char *block_name, void 
> > > *host_addr,
> > > +                                       ram_addr_t offset, ram_addr_t 
> > > length,
> > > +                                       void *opaque)
> > > +{
> > > +    MigrationIncomingState *mis = opaque;
> > > +    uint64_t tokern[2];
> > 
> > "tokern"?
> 
> Now "to_kernel"

Ah!  I thought it was just mispelled "token".

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

pgptl9czI207l.pgp
Description: PGP signature