Re: [Xen-devel] [PATCH v2 13/19] hvmloader: construct SRAT

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, Dec 10, 2014 at 11:06:20AM +0000, Jan Beulich wrote:
> >>> On 10.12.14 at 11:54, <wei.liu2@xxxxxxxxxx> wrote:
> > On Wed, Dec 10, 2014 at 08:20:38AM +0000, Jan Beulich wrote:
> >> >>> On 09.12.14 at 19:06, <wei.liu2@xxxxxxxxxx> wrote:
> >> > On Tue, Dec 09, 2014 at 04:53:40PM +0000, Jan Beulich wrote:
> >> >> >>> On 01.12.14 at 16:33, <wei.liu2@xxxxxxxxxx> wrote:
> >> >> > +        memset(memory, 0, sizeof(*memory));
> >> >> > +        memory->type          = ACPI_MEMORY_AFFINITY;
> >> >> > +        memory->length        = sizeof(*memory);
> >> >> > +        memory->domain        = vmemrange[i].nid;
> >> >> > +        memory->flags         = ACPI_MEM_AFFIN_ENABLED;
> >> >> > +        memory->base_address  = vmemrange[i].start;
> >> >> > +        memory->mem_length    = mem;
> >> >> > +        memory++;
> >> >> > +    }
> >> >> > +
> >> >> > +    srat->header.length = size;
> >> >> 
> >> >> Mind checking size == memory - p here?
> >> >> 
> >> > 
> >> > Why? There doesn't seem to be anything that would cause memory -p !=
> >> > size in between during runtime.
> >> 
> >> Except for that original calculation being wrong - that's what I would
> >> mean such a check to verify.
> >> 
> > 
> > Do you mean the code is wrong? I don't think so.
> 
> No, the code looks right. It's just that two disconnected
> calculations easily get out of sync when someone later changes
> them.
> 

I see.

> > Even if I have 
> > 
> > +    if ( ((unsigned long)memory) - ((unsigned long)p) != size )
> > +        return NULL;
> > +
> > 
> > Hvmloader doesn't complain, i.e. I don't see error message printed out
> > in the construct_secondary_tables.
> > 
> > Anyway, if the above snippet is what you want, I can add it.
> 
> I was actually more after a BUG_ON() / ASSERT() kind of thing.

Ack.

> 
> Jan

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