On 6/21/2017 2:37 AM, 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 >> >> Reviewed-by: Borislav Petkov <bp at suse.de> >> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com> >> --- >> arch/x86/mm/ioremap.c | 7 +++++-- >> 1 file changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c >> index 4c1b5fd..a382ba9 100644 >> --- a/arch/x86/mm/ioremap.c >> +++ b/arch/x86/mm/ioremap.c >> @@ -13,6 +13,7 @@ >> #include <linux/slab.h> >> #include <linux/vmalloc.h> >> #include <linux/mmiotrace.h> >> +#include <linux/mem_encrypt.h> >> >> #include <asm/set_memory.h> >> #include <asm/e820/api.h> >> @@ -106,9 +107,11 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, >> } >> >> /* >> - * Don't remap the low PCI/ISA area, it's always mapped.. >> + * Don't remap the low PCI/ISA area, it's always mapped. >> + * But if SME is active, skip this so that the encryption bit >> + * doesn't get set. >> */ >> - if (is_ISA_range(phys_addr, last_addr)) >> + if (is_ISA_range(phys_addr, last_addr) && !sme_active()) >> return (__force void __iomem *)phys_to_virt(phys_addr); > > More thoughts about that. > > Making this conditional on !sme_active() is not the best idea. I'd rather > remove that whole thing and make it unconditional so the code pathes get > always exercised and any subtle wreckage is detected on a broader base and > not only on that hard to access and debug SME capable machine owned by Joe > User. Ok, that sounds good. I'll remove the check and usage of phys_to_virt() and update the changelog with additional detail about that. Thanks, Tom > > Thanks, > > tglx >
