Re: [Qemu-devel] [PATCH v4 25/47] postcopy: OS support test

[David Gibson]

On Fri, Oct 03, 2014 at 06:47:31PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> Provide a check to see if the OS we're running on has all the bits
> needed for postcopy.
> 
> Creates postcopy-ram.c which will get most of the other helpers we need.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  Makefile.objs                    |   2 +-
>  include/migration/postcopy-ram.h |  19 +++++
>  postcopy-ram.c                   | 160 
> +++++++++++++++++++++++++++++++++++++++
>  savevm.c                         |   6 ++
>  4 files changed, 186 insertions(+), 1 deletion(-)
>  create mode 100644 include/migration/postcopy-ram.h
>  create mode 100644 postcopy-ram.c
> 
> diff --git a/Makefile.objs b/Makefile.objs
> index 97db978..fa0a3a0 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -54,7 +54,7 @@ common-obj-y += qemu-file.o
>  common-obj-$(CONFIG_RDMA) += migration-rdma.o
>  common-obj-y += qemu-char.o #aio.o
>  common-obj-y += block-migration.o
> -common-obj-y += page_cache.o xbzrle.o
> +common-obj-y += page_cache.o xbzrle.o postcopy-ram.o
>  
>  common-obj-$(CONFIG_POSIX) += migration-exec.o migration-unix.o 
> migration-fd.o
>  
> diff --git a/include/migration/postcopy-ram.h 
> b/include/migration/postcopy-ram.h
> new file mode 100644
> index 0000000..dcd1afa
> --- /dev/null
> +++ b/include/migration/postcopy-ram.h
> @@ -0,0 +1,19 @@
> +/*
> + * Postcopy migration for RAM
> + *
> + * Copyright 2013 Red Hat, Inc. and/or its affiliates
> + *
> + * Authors:
> + *  Dave Gilbert  <address@hidden>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +#ifndef QEMU_POSTCOPY_RAM_H
> +#define QEMU_POSTCOPY_RAM_H
> +
> +/* Return 0 if the host supports everything we need to do postcopy-ram */
> +int postcopy_ram_hosttest(void);

Maybe postcopy_supported_by_host() would be a bit clearer?

[snip]
> +#ifdef HOST_X86_64
> + /* NOTE: These are Andrea's 3.15.0 world */

I thought the usual approach in qemu was to import the updated headers
first in a separate patch, rather than embeddeding new defines.


> +#ifndef MADV_USERFAULT
> +#define MADV_USERFAULT   18
> +#define MADV_NOUSERFAULT 19
> +#endif
> +
> +#ifndef __NR_remap_anon_pages
> +#define __NR_remap_anon_pages 321
> +#endif
> +
> +#ifndef __NR_userfaultfd
> +#define __NR_userfaultfd 322
> +#endif
> +
> +#endif
> +
> +#ifndef USERFAULTFD_PROTOCOL
> +#define USERFAULTFD_PROTOCOL (uint64_t)0xaa
> +#endif
> +
> +#endif

-- 
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

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