Re: [Qemu-devel] [PATCH v3 2/2] ramblock: add new hmp command "info ramblock"

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

* Peter Xu (peterx@redhat.com) wrote:
> To dump information about ramblocks. It looks like:
> 
> (qemu) info ramblock
>               Block Name    PSize              Offset               Used              Total
>             /objects/mem       2M  0x0000000000000000 0x0000000080000000 0x0000000080000000
>                 vga.vram       4K  0x0000000080060000 0x0000000001000000 0x0000000001000000
>     /rom@etc/acpi/tables       4K  0x00000000810b0000 0x0000000000020000 0x0000000000200000
>                  pc.bios       4K  0x0000000080000000 0x0000000000040000 0x0000000000040000
>   0000:00:03.0/e1000.rom       4K  0x0000000081070000 0x0000000000040000 0x0000000000040000
>                   pc.rom       4K  0x0000000080040000 0x0000000000020000 0x0000000000020000
>     0000:00:02.0/vga.rom       4K  0x0000000081060000 0x0000000000010000 0x0000000000010000
>    /rom@etc/table-loader       4K  0x00000000812b0000 0x0000000000001000 0x0000000000001000
>       /rom@etc/acpi/rsdp       4K  0x00000000812b1000 0x0000000000001000 0x0000000000001000
> 
> Ramblock is something hidden internally in QEMU implementation, and this
> command should only be used by mostly QEMU developers on RAM stuff. It
> is not a command suitable for QMP interface. So only HMP interface is
> provided for it.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  exec.c                 | 36 ++++++++++++++++++++++++++++++++++++
>  hmp-commands-info.hx   | 14 ++++++++++++++
>  hmp.c                  |  6 ++++++
>  hmp.h                  |  1 +
>  include/exec/ramlist.h |  1 +
>  5 files changed, 58 insertions(+)
> 
> diff --git a/exec.c b/exec.c
> index 50519ae..9b9d16e 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -71,6 +71,8 @@
>  #include "qemu/mmap-alloc.h"
>  #endif
>  
> +#include "monitor/monitor.h"
> +
>  //#define DEBUG_SUBPAGE
>  
>  #if !defined(CONFIG_USER_ONLY)
> @@ -1333,6 +1335,40 @@ void qemu_mutex_unlock_ramlist(void)
>      qemu_mutex_unlock(&ram_list.mutex);
>  }
>  
> +static const char *page_size_to_str(size_t psize)
> +{
> +    switch (psize) {
> +    case 0x1000:
> +        return "4K";
> +    case 0x10000:
> +        return "64K";
> +    case 0x200000:
> +        return "2M";
> +    case 0x40000000:
> +        return "1G";

That's not very portable; other platforms have other sizes, for example
I think ARM has 16kB as one option, and I'm pretty sure the huge-pages
on Power are a different size.
Hmm, we already have
                     qemu-io-cmds.c:cvtstr and
       qapi/string-output-visitor.c:print_type_size

to print sizes nicely; it's a pity we can't use them somehow rather
than having a 3rd similar function.

> +    default:
> +        return "N/A";
> +    }
> +}
> +
> +void ram_block_dump(Monitor *mon)
> +{
> +    RAMBlock *block;
> +
> +    rcu_read_lock();
> +    monitor_printf(mon, "%24s %8s  %18s %18s %18s\n",
> +                   "Block Name", "PSize", "Offset", "Used", "Total");
> +    RAMBLOCK_FOREACH(block) {
> +        monitor_printf(mon, "%24s %8s  0x%016" PRIx64 " 0x%016" PRIx64
> +                       " 0x%016" PRIx64 "\n", block->idstr,
> +                       page_size_to_str(block->page_size),
> +                       (uint64_t)block->offset,
> +                       (uint64_t)block->used_length,
> +                       (uint64_t)block->max_length);
> +    }

Yes that should work, I remember there's a RAM_ADDR_FMT macro that's
supposed to be usable for ram_addr_t, but that's fine.

Dave

> +    rcu_read_unlock();
> +}
> +
>  #ifdef __linux__
>  /*
>   * FIXME TOCTTOU: this iterates over memory backends' mem-path, which
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index a53f105..ae16901 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -788,6 +788,20 @@ Display the latest dump status.
>  ETEXI
>  
>      {
> +        .name       = "ramblock",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "Display system ramblock information",
> +        .cmd        = hmp_info_ramblock,
> +    },
> +
> +STEXI
> +@item info ramblock
> +@findex ramblock
> +Dump all the ramblocks of the system.
> +ETEXI
> +
> +    {
>          .name       = "hotpluggable-cpus",
>          .args_type  = "",
>          .params     = "",
> diff --git a/hmp.c b/hmp.c
> index ab407d6..8369388 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -37,6 +37,7 @@
>  #include "qemu-io.h"
>  #include "qemu/cutils.h"
>  #include "qemu/error-report.h"
> +#include "exec/ramlist.h"
>  #include "hw/intc/intc.h"
>  
>  #ifdef CONFIG_SPICE
> @@ -2563,6 +2564,11 @@ void hmp_info_dump(Monitor *mon, const QDict *qdict)
>      qapi_free_DumpQueryResult(result);
>  }
>  
> +void hmp_info_ramblock(Monitor *mon, const QDict *qdict)
> +{
> +    ram_block_dump(mon);
> +}
> +
>  void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict)
>  {
>      Error *err = NULL;
> diff --git a/hmp.h b/hmp.h
> index 799fd37..7353b67 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -136,6 +136,7 @@ void hmp_rocker_ports(Monitor *mon, const QDict *qdict);
>  void hmp_rocker_of_dpa_flows(Monitor *mon, const QDict *qdict);
>  void hmp_rocker_of_dpa_groups(Monitor *mon, const QDict *qdict);
>  void hmp_info_dump(Monitor *mon, const QDict *qdict);
> +void hmp_info_ramblock(Monitor *mon, const QDict *qdict);
>  void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict);
>  void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict);
>  
> diff --git a/include/exec/ramlist.h b/include/exec/ramlist.h
> index f1c6b45..2e2ac6c 100644
> --- a/include/exec/ramlist.h
> +++ b/include/exec/ramlist.h
> @@ -73,5 +73,6 @@ void ram_block_notifier_remove(RAMBlockNotifier *n);
>  void ram_block_notify_add(void *host, size_t size);
>  void ram_block_notify_remove(void *host, size_t size);
>  
> +void ram_block_dump(Monitor *mon);
>  
>  #endif /* RAMLIST_H */
> -- 
> 2.7.4
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK