On Mon, May 22, 2017 at 9:30 AM, Mike Travis <mike.tra...@hpe.com> wrote: > > > On 5/21/2017 4:17 PM, Baoquan He wrote: > > Sorry, forget 'To' Mike, Russ and Frank > > On 05/22/17 at 07:14am, Baoquan He wrote: > > On 05/21/17 at 01:38pm, Thomas Garnier wrote: > > On Sat, May 20, 2017 at 5:02 AM, Baoquan He <b...@redhat.com> wrote: > > arch/x86/mm/kaslr.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c > index aed2064..20b0456 100644 > --- a/arch/x86/mm/kaslr.c > +++ b/arch/x86/mm/kaslr.c > @@ -27,6 +27,7 @@ > #include <asm/pgtable.h> > #include <asm/setup.h> > #include <asm/kaslr.h> > +#include <asm/uv/uv.h> > > #include "mm_internal.h" > > @@ -123,7 +124,7 @@ void __init kernel_randomize_memory(void) > CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING; > > /* Adapt phyiscal memory region size based on available memory */ > - if (memory_tb < kaslr_regions[0].size_tb) > + if (memory_tb < kaslr_regions[0].size_tb && !is_early_uv_system()) > > Given your example, any way we could just restrict memory_tb to be > 32TB? Or different configurations will result in different mappings? > > Thanks for looking into this, Thomas! > > For that machine where I used to reproduce the bug and test, 32TB memory > need be mapped to the direct mapping region. I am not sure if SGI UV > system has larger MMIOH region now or in the future in different machine. > If they have machine owning MMIOH region bigger than 64TB, then it's a > problem SGI UV need fix because that will break system whether kaslr > enabled or not. > > Hi Mike, Russ and Frank, > > About Thomas's question, could you help answer it? Could other SGI UV > system has MMIOH region bigger than 32TB? > > > While the region is much smaller it can occupy address space > 32TB, up to > 64TB - <MMIOH size>. > On a system with 64TB, part of the address space is taken from RAM to > accommodate this region. > This has been true since UV1.
I see, it would be better to know the different places to tailor the memory_tb accordingly. I understand that might be difficult to do and I rather have KASLR memory randomization working for now. Reviewed-by: thgar...@google.com > > Thanks > Baoquan > > kaslr_regions[0].size_tb = memory_tb; > > /* Calculate entropy available between regions */ > > -- Thomas
