Re: [Qemu-devel] [PATCH] HMP: support specifying dump format for dump-guest-memory

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 01/04/14 10:33, Qiao Nuohan wrote:
> Dumping guest memory is available to specify the dump format now. This patch
> adds options '-z|-l|-s' to HMP command dump-guest-memory to specify dumping in
> kdump-compression format, with zlib/lzo/snappy compression. And without these
> options ELF format will be used.
> 
> The discussion about this feature is here:
> 
> http://lists.nongnu.org/archive/html/qemu-devel/2014-03/msg04235.html
> 
> Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com>
> Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com>

Looks good. I was able to take a zlib dump on s390. 


> ---
>  hmp-commands.hx | 11 +++++++----
>  hmp.c           | 25 ++++++++++++++++++++++++-
>  2 files changed, 31 insertions(+), 5 deletions(-)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index f3fc514..4b9989f 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -998,8 +998,8 @@ ETEXI
> 
>      {
>          .name       = "dump-guest-memory",
> -        .args_type  = "paging:-p,filename:F,begin:i?,length:i?",
> -        .params     = "[-p] filename [begin] [length]",
> +        .args_type  = "paging:-p,zlib:-z,lzo:-l,snappy:-s,filename:F,begin:i?,length:i?",
> +        .params     = "[-p] [-z|-l|-s] filename [begin] [length]",
>          .help       = "dump guest memory to file"
>                        "\n\t\t\t begin(optional): the starting physical address"
>                        "\n\t\t\t length(optional): the memory size, in bytes",
> @@ -1008,12 +1008,15 @@ ETEXI
> 
> 
>  STEXI
> -@item dump-guest-memory [-p] @var{protocol} @var{begin} @var{length}
> +@item dump-guest-memory [-p] [-z|-l|-s] @var{protocol} @var{begin} @var{length}
>  @findex dump-guest-memory
>  Dump guest memory to @var{protocol}. The file can be processed with crash or
> -gdb.
> +gdb. Without -z|-l|-s, the dump format is ELF.
>    filename: dump file name
>      paging: do paging to get guest's memory mapping
> +      zlib: dump in kdump-compressed format, with zlib compression
> +       lzo: dump in kdump-compressed format, with lzo compression
> +    snappy: dump in kdump-compressed format, with snappy compression
>       begin: the starting physical address. It's optional, and should be
>              specified with length together.
>      length: the memory size, in bytes. It's optional, and should be specified
> diff --git a/hmp.c b/hmp.c
> index 2f279c4..37c3961 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -1308,16 +1308,39 @@ void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict)
>  {
>      Error *errp = NULL;
>      int paging = qdict_get_try_bool(qdict, "paging", 0);
> +    int zlib = qdict_get_try_bool(qdict, "zlib", 0);
> +    int lzo = qdict_get_try_bool(qdict, "lzo", 0);
> +    int snappy = qdict_get_try_bool(qdict, "snappy", 0);
>      const char *file = qdict_get_str(qdict, "filename");
>      bool has_begin = qdict_haskey(qdict, "begin");
>      bool has_length = qdict_haskey(qdict, "length");
> -    /* kdump-compressed format is not supported for HMP */
>      bool has_format = false;
>      int64_t begin = 0;
>      int64_t length = 0;
>      enum DumpGuestMemoryFormat dump_format = DUMP_GUEST_MEMORY_FORMAT_ELF;
>      char *prot;
> 
> +    if ((zlib + lzo + snappy) > 1) {
> +        error_setg(&errp, "only one of '-z|-l|-s' can be set");
> +        hmp_handle_error(mon, &errp);
> +        return;
> +    }
> +
> +    if (zlib) {
> +        has_format = true;
> +        dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_ZLIB;
> +    }
> +
> +    if (lzo) {
> +        has_format = true;
> +        dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO;
> +    }
> +
> +    if (snappy) {
> +        has_format = true;
> +        dump_format = DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY;
> +    }
> +
>      if (has_begin) {
>          begin = qdict_get_int(qdict, "begin");
>      }
>