Re: [Qemu-devel] [Qemu-ppc] [PATCH for-2.13] Add host_memory_backend_pagesize() helper

From: David Gibson <david@gibson.dropbear.id.au>
To: Greg Kurz <groug@kaod.org>
Cc: ehabkost@redhat.com, imammedo@redhat.com, pbonzini@redhat.com,
	qemu-ppc@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH for-2.13] Add host_memory_backend_pagesize() helper
Date: Tue, 3 Apr 2018 15:31:46 +1000	[thread overview]
Message-ID: <20180403053146.GB1984@umbus.fritz.box> (raw)
In-Reply-To: <20180329083748.15264f31@bahia.lan>

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On Thu, Mar 29, 2018 at 08:37:48AM +0200, Greg Kurz wrote:
> On Thu, 29 Mar 2018 16:25:37 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > There are a couple places (one generic, one target specific) where we need
> > to get the host page size associated with a particular memory backend.  I
> > have some upcoming code which will add another place which wants this.  So,
> > for convenience, add a helper function to calculate this.
> > 
> > host_memory_backend_pagesize() returns the host pagesize for a given
> > HostMemoryBackend object, or for the default backend (-mem-path) if passed
> > NULL.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> 
> The idea is good but there's a small issue. See below.
> 
> >  backends/hostmem.c       | 20 ++++++++++++++++++++
> >  exec.c                   | 21 +++++----------------
> >  include/sysemu/hostmem.h |  2 ++
> >  target/ppc/kvm.c         | 10 +---------
> >  4 files changed, 28 insertions(+), 25 deletions(-)
> > 
> > diff --git a/backends/hostmem.c b/backends/hostmem.c
> > index f61093654e..b6a60cfc5d 100644
> > --- a/backends/hostmem.c
> > +++ b/backends/hostmem.c
> > @@ -18,6 +18,7 @@
> >  #include "qapi/visitor.h"
> >  #include "qemu/config-file.h"
> >  #include "qom/object_interfaces.h"
> > +#include "qemu/mmap-alloc.h"
> >  
> >  #ifdef CONFIG_NUMA
> >  #include <numaif.h>
> > @@ -262,6 +263,25 @@ bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
> >      return backend->is_mapped;
> >  }
> >  
> > +long host_memory_backend_pagesize(HostMemoryBackend *memdev)
> > +{
> > +    const char *path = NULL;
> > +
> > +#ifdef __linux__
> > +    if (memdev) {
> > +        path = object_property_get_str(OBJECT(memdev), "mem-path", NULL);
> 
> object_property_get_str() returns an allocated string. It should be freed
> before returning.

Ah, nice catch, I'll correct that.

-- 
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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