2014-09-18 19:46 GMT+04:00 Dave Hansen <dave@xxxxxxxx>: > > From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > > Peter Anvin says: >> 0xffff880000000000 is the lowest usable address because we have >> agreed to leave 0xffff800000000000-0xffff880000000000 for the >> hypervisor or other non-OS uses. > > Let's call this out in the documentation. > > This came up during the kernel address sanitizer discussions > where it was proposed to use this area for other kernel things. > > Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> > Cc: x86@xxxxxxxxxx > Cc: linux-mm@xxxxxxxxx > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > --- > > b/Documentation/x86/x86_64/mm.txt | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff -puN Documentation/x86/x86_64/mm.txt~update-x86-mm-doc Documentation/x86/x86_64/mm.txt > --- a/Documentation/x86/x86_64/mm.txt~update-x86-mm-doc 2014-09-17 21:44:10.499781092 -0700 > +++ b/Documentation/x86/x86_64/mm.txt 2014-09-17 21:44:31.852740822 -0700 > @@ -5,7 +5,7 @@ Virtual memory map with 4 level page tab > > 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm > hole caused by [48:63] sign extension > -ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole > +ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole, reserved for hypervisor ffff800000000000 - ffff87ffffffffff (=43 bits) guard hole, reserved for hypervisor > ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory > ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole > ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space > _ -- Best regards, Andrey Ryabinin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>