Re: [PATCH -v2] Monitor command: pfa2hva, translate guest physical address to host virtual address

[Anthony Liguori <aliguori@xxxxxxxxxxxxxxxxxx>]

On 11/01/2010 11:09 AM, Marcelo Tosatti wrote:
> On Tue, Oct 26, 2010 at 10:39:48AM +0800, Huang Ying wrote:
>    
> > Author: Max Asbock<masbock@xxxxxxxxxxxxxxxxxx>
> >
> > Add command pfa2hva to translate guest physical address to host
> > virtual address.
> >
> > The pfa2hva command provides one step in a chain of translations from
> > guest virtual to guest physical to host virtual to host physical. Host
> > physical is then used to inject a machine check error. As a
> > consequence the HWPOISON code on the host and the MCE injection code
> > in qemu-kvm are exercised.
> >
> > v2:
> >
> > - Add QMP support
> >      
>
> Looks good to me. Anthony?
>    

The translation is not stable so this is really a bad interface.

It definitely shouldn't be a QMP command and I don't think it's 
generally useful enough that it should be a monitor command.

It's impossible to use correctly as a general interface.

I gave this feedback when it was initially submitted.

Regards,

Anthony Liguori

> > Signed-off-by: Max Asbock<masbock@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Jiajia Zheng<jiajia.zheng@xxxxxxxxx>
> > Signed-off-by: Huang Ying<ying.huang@xxxxxxxxx>
> > ---
> >   hmp-commands.hx |   15 +++++++++++++++
> >   monitor.c       |   22 ++++++++++++++++++++++
> >   qmp-commands.hx |   27 +++++++++++++++++++++++++++
> >   3 files changed, 64 insertions(+)
> >
> > --- a/monitor.c
> > +++ b/monitor.c
> > @@ -2272,6 +2272,28 @@ static void do_inject_mce(Monitor *mon,
> >   }
> >   #endif
> >
> > +static void do_pfa2hva_print(Monitor *mon, const QObject *data)
> > +{
> > +    QInt *qint;
> > +
> > +    qint = qobject_to_qint(data);
> > +    monitor_printf(mon, "0x%lx\n", (unsigned long)qint->value);
> > +}
> > +
> > +static int do_pfa2hva(Monitor *mon, const QDict *qdict, QObject **ret_data)
> > +{
> > +    target_phys_addr_t paddr;
> > +    target_phys_addr_t size = TARGET_PAGE_SIZE;
> > +    void *vaddr;
> > +
> > +    paddr = qdict_get_int(qdict, "addr");
> > +    vaddr = cpu_physical_memory_map(paddr,&size, 0);
> > +    cpu_physical_memory_unmap(vaddr, size, 0, 0);
> > +    *ret_data = qobject_from_jsonf("%ld", (unsigned long)vaddr);
> > +
> > +    return 0;
> > +}
> > +
> >   static int do_getfd(Monitor *mon, const QDict *qdict, QObject **ret_data)
> >   {
> >       const char *fdname = qdict_get_str(qdict, "fdname");
> > --- a/hmp-commands.hx
> > +++ b/hmp-commands.hx
> > @@ -293,6 +293,21 @@ Start gdbserver session (default @var{po
> >   ETEXI
> >
> >       {
> > +        .name       = "pfa2hva",
> > +        .args_type  = "fmt:/,addr:l",
> > +        .params     = "/fmt addr",
> > +        .help       = "translate guest physical 'addr' to host virtual address",
> > +        .user_print = do_pfa2hva_print,
> > +        .mhandler.cmd_new = do_pfa2hva,
> > +    },
> > +
> > +STEXI
> > +@item pfa2hva @var{addr}
> > +@findex pfa2hva
> > +Translate guest physical @var{addr} to host virtual address.
> > +ETEXI
> > +
> > +    {
> >           .name       = "x",
> >           .args_type  = "fmt:/,addr:l",
> >           .params     = "/fmt addr",
> > --- a/qmp-commands.hx
> > +++ b/qmp-commands.hx
> > @@ -738,6 +738,33 @@ Example:
> >   EQMP
> >
> >       {
> > +        .name       = "pfa2hva",
> > +        .args_type  = "addr:l",
> > +        .params     = "addr",
> > +        .help       = "translate guest physical 'addr' to host virtual address",
> > +        .user_print = do_pfa2hva_print,
> > +        .mhandler.cmd_new = do_pfa2hva,
> > +    },
> > +
> > +SQMP
> > +pfa2hva
> > +---
> > +
> > +Translate guest physical 'addr' to host virtual address.
> > +
> > +Arguments:
> > +
> > +- "addr": the guest physical address
> > +
> > +Example:
> > +
> > +->  { "execute": "pfa2hva",
> > +		"arguments": { "addr": 196608 } }
> > +<- { "return": 139888084717568 }
> > +
> > +EQMP
> > +
> > +    {
> >           .name       = "qmp_capabilities",
> >           .args_type  = "",
> >           .params     = "",
> >
> >      

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