On 6/20/2017 3:55 PM, Thomas Gleixner wrote: > On Fri, 16 Jun 2017, Tom Lendacky wrote: > >> Currently there is a check if the address being mapped is in the ISA >> range (is_ISA_range()), and if it is then phys_to_virt() is used to >> perform the mapping. When SME is active, however, this will result >> in the mapping having the encryption bit set when it is expected that >> an ioremap() should not have the encryption bit set. So only use the >> phys_to_virt() function if SME is not active > > This does not make sense to me. What the heck has phys_to_virt() to do with > the encryption bit. Especially why would the encryption bit be set on that > mapping in the first place? The default is that all entries that get added to the pagetables have the encryption bit set unless specifically overridden. Any __va() or phys_to_virt() calls will result in a pagetable mapping that has the encryption bit set. For ioremap, the PAGE_KERNEL_IO protection is used which will not/does not have the encryption bit set. > > I'm probably missing something, but this want's some coherent explanation > understandable by mere mortals both in the changelog and the code comment. I'll add some additional info to the changelog and code. Thanks, Tom > > Thanks, > > tglx >
