Hi everybody, Here's updated version of my patchset that brings support of MKTME. It's not yet complete, but I think it worth sharing to get early feedback. Things that are missing: - kmap() is not yet wired up to support tempoprary mappings of encrypted pages. It's requried to allow kernel to access encrypted memory. - Interface to manipulate encryption keys. - Interface to create encrypted userspace mappings. - IOMMU support. What has been done: - PCONFIG, TME and MKTME enumeration. - In-kernel helper that allows to program encryption keys into CPU. - Allocation and freeing encrypted pages. - Helpers to find out if a VMA/anon_vma/page is encrypted and with what KeyID. Any feedback is welcome. ------------------------------------------------------------------------------ Multikey Total Memory Encryption (MKTME)[1] is a technology that allows transparent memory encryption in upcoming Intel platforms. MKTME is built on top of TME. TME allows encryption of the entirety of system memory using a single key. MKTME allows to have multiple encryption domains, each having own key -- different memory pages can be encrypted with different keys. Key design points of Intel MKTME: - Initial HW implementation would support upto 63 keys (plus one default TME key). But the number of keys may be as low as 3, depending to SKU and BIOS settings - To access encrypted memory you need to use mapping with proper KeyID int the page table entry. KeyID is encoded in upper bits of PFN in page table entry. This means we cannot use direct map to access encrypted memory from kernel side. My idea is to re-use kmap() interface to get proper temporary mapping on kernel side. - CPU does not enforce coherency between mappings of the same physical page with different KeyIDs or encryption keys. We wound need to take care about flushing cache on allocation of encrypted page and on returning it back to free pool. - For managing keys, there's MKTME_KEY_PROGRAM leaf of the new PCONFIG (platform configuration) instruction. It allows load and clear keys associated with a KeyID. You can also ask CPU to generate a key for you or disable memory encryption when a KeyID is used. [1] https://software.intel.com/sites/default/files/managed/a5/16/Multi-Key-Total-Memory-Encryption-Spec.pdf Kirill A. Shutemov (22): x86/cpufeatures: Add Intel Total Memory Encryption cpufeature x86/tme: Detect if TME and MKTME is activated by BIOS x86/cpufeatures: Add Intel PCONFIG cpufeature x86/pconfig: Detect PCONFIG targets x86/pconfig: Provide defines and helper to run MKTME_KEY_PROG leaf x86/mm: Decouple dynamic __PHYSICAL_MASK from AMD SME x86/mm: Mask out KeyID bits from page table entry pfn mm: Introduce __GFP_ENCRYPT mm, rmap: Add arch-specific field into anon_vma mm/shmem: Zero out unused vma fields in shmem_pseudo_vma_init() mm: Use __GFP_ENCRYPT for pages in encrypted VMAs mm: Do no merge vma with different encryption KeyIDs mm, rmap: Free encrypted pages once mapcount drops to zero mm, khugepaged: Do not collapse pages in encrypted VMAs x86/mm: Introduce variables to store number, shift and mask of KeyIDs x86/mm: Preserve KeyID on pte_modify() and pgprot_modify() x86/mm: Implement vma_is_encrypted() and vma_keyid() x86/mm: Handle allocation of encrypted pages x86/mm: Implement free_encrypt_page() x86/mm: Implement anon_vma_encrypted() and anon_vma_keyid() x86/mm: Introduce page_keyid() and page_encrypted() x86: Introduce CONFIG_X86_INTEL_MKTME arch/x86/Kconfig | 21 +++++++ arch/x86/boot/compressed/kaslr_64.c | 3 + arch/x86/include/asm/cpufeatures.h | 2 + arch/x86/include/asm/intel_pconfig.h | 65 +++++++++++++++++++ arch/x86/include/asm/mktme.h | 56 +++++++++++++++++ arch/x86/include/asm/page.h | 13 +++- arch/x86/include/asm/page_types.h | 8 ++- arch/x86/include/asm/pgtable_types.h | 7 ++- arch/x86/kernel/cpu/Makefile | 2 +- arch/x86/kernel/cpu/intel.c | 119 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/cpu/intel_pconfig.c | 82 ++++++++++++++++++++++++ arch/x86/mm/Makefile | 2 + arch/x86/mm/mem_encrypt_identity.c | 3 + arch/x86/mm/mktme.c | 101 +++++++++++++++++++++++++++++ arch/x86/mm/pgtable.c | 5 ++ include/linux/gfp.h | 29 +++++++-- include/linux/mm.h | 17 +++++ include/linux/rmap.h | 6 ++ include/trace/events/mmflags.h | 1 + mm/Kconfig | 3 + mm/khugepaged.c | 2 + mm/mempolicy.c | 3 + mm/mmap.c | 3 +- mm/page_alloc.c | 3 + mm/rmap.c | 49 +++++++++++++-- mm/shmem.c | 3 +- tools/perf/builtin-kmem.c | 1 + 27 files changed, 590 insertions(+), 19 deletions(-) create mode 100644 arch/x86/include/asm/intel_pconfig.h create mode 100644 arch/x86/include/asm/mktme.h create mode 100644 arch/x86/kernel/cpu/intel_pconfig.c create mode 100644 arch/x86/mm/mktme.c -- 2.16.1 -- 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>
