From: Jason Gunthorpe jgg@nvidia.com
commit f8f6ae5d077a9bdaf5cbf2ac960a5d1a04b47482 upstream.
The purpose of io_remap_pfn_range() is to map IO memory, such as a memory mapped IO exposed through a PCI BAR. IO devices do not understand encryption, so this memory must always be decrypted. Automatically call pgprot_decrypted() as part of the generic implementation.
This fixes a bug where enabling AMD SME causes subsystems, such as RDMA, using io_remap_pfn_range() to expose BAR pages to user space to fail. The CPU will encrypt access to those BAR pages instead of passing unencrypted IO directly to the device.
Places not mapping IO should use remap_pfn_range().
Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption") Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Cc: Arnd Bergmann arnd@arndb.de Cc: Tom Lendacky thomas.lendacky@amd.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Andrey Ryabinin aryabinin@virtuozzo.com Cc: Borislav Petkov bp@alien8.de Cc: Brijesh Singh brijesh.singh@amd.com Cc: Jonathan Corbet corbet@lwn.net Cc: Dmitry Vyukov dvyukov@google.com Cc: "Dave Young" dyoung@redhat.com Cc: Alexander Potapenko glider@google.com Cc: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Cc: Andy Lutomirski luto@kernel.org Cc: Larry Woodman lwoodman@redhat.com Cc: Matt Fleming matt@codeblueprint.co.uk Cc: Ingo Molnar mingo@kernel.org Cc: "Michael S. Tsirkin" mst@redhat.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Rik van Riel riel@redhat.com Cc: Toshimitsu Kani toshi.kani@hpe.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/0-v1-025d64bdf6c4+e-amd_sme_fix_jgg@nvidia.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/asm-generic/pgtable.h | 4 ---- include/linux/mm.h | 9 +++++++++ 2 files changed, 9 insertions(+), 4 deletions(-)
--- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -1069,10 +1069,6 @@ static inline bool arch_has_pfn_modify_c
#endif /* !__ASSEMBLY__ */
-#ifndef io_remap_pfn_range -#define io_remap_pfn_range remap_pfn_range -#endif - #ifndef has_transparent_hugepage #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define has_transparent_hugepage() 1 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2422,6 +2422,15 @@ static inline int vm_fault_to_errno(int return 0; }
+#ifndef io_remap_pfn_range +static inline int io_remap_pfn_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long pfn, + unsigned long size, pgprot_t prot) +{ + return remap_pfn_range(vma, addr, pfn, size, pgprot_decrypted(prot)); +} +#endif + typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, void *data); extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,