Re: [Xen-devel] [PATCH] increase maxmem before calling xc_domain_populate_physmap

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 25 Nov 2014, Andrew Cooper wrote:
> On 25/11/14 17:45, Stefano Stabellini wrote:
> > Increase maxmem before calling xc_domain_populate_physmap_exact to avoid
> > the risk of running out of guest memory. This way we can also avoid
> > complex memory calculations in libxl at domain construction time.
> >
> > This patch fixes an abort() when assigning more than 4 NICs to a VM.
> >
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> >
> > diff --git a/xen-hvm.c b/xen-hvm.c
> > index 5c69a8d..38e08c3 100644
> > --- a/xen-hvm.c
> > +++ b/xen-hvm.c
> > @@ -218,6 +218,7 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t 
> > size, MemoryRegion *mr)
> >      unsigned long nr_pfn;
> >      xen_pfn_t *pfn_list;
> >      int i;
> > +    xc_dominfo_t info;
> >  
> >      if (runstate_check(RUN_STATE_INMIGRATE)) {
> >          /* RAM already populated in Xen */
> > @@ -240,6 +241,13 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t 
> > size, MemoryRegion *mr)
> >          pfn_list[i] = (ram_addr >> TARGET_PAGE_BITS) + i;
> >      }
> >  
> > +    if (xc_domain_getinfo(xen_xc, xen_domid, 1, &info) < 0) {
> 
> xc_domain_getinfo()'s interface is mad, and provides no guarantee that
> it returns the information for the domain you requested.  It also won't
> return -1 on error.  The correct error handing is:
> 
> (xc_domain_getinfo(xen_xc, xen_domid, 1, &info) != 1) || (info.domid !=
> xen_domid)

It might be wiser to switch to xc_domain_getinfolist


> ~Andrew
> 
> > +        hw_error("xc_domain_getinfo failed");
> > +    }
> > +    if (xc_domain_setmaxmem(xen_xc, xen_domid, info.max_memkb +
> > +                            (nr_pfn * XC_PAGE_SIZE / 1024)) < 0) {
> > +        hw_error("xc_domain_setmaxmem failed");
> > +    }
> >      if (xc_domain_populate_physmap_exact(xen_xc, xen_domid, nr_pfn, 0, 0, 
> > pfn_list)) {
> >          hw_error("xen: failed to populate ram at " RAM_ADDR_FMT, ram_addr);
> >      }
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel
> 
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel