One piece that seems missing here is the handling of the vmm communication exception. What's the plan for non-automatic exits? In particular, what's the plan for emulated devices that are currently accessed through MMIO (e.g. the IOAPIC)? Maybe I'm getting ahead of myself: What's the testing story? (since I don't think linux would boot with these patches, I'm curious what you are doing to ensure these pieces work) On Fri, Oct 20, 2017 at 7:30 AM, Brijesh Singh <brijesh.singh@xxxxxxx> wrote: > This part of Secure Encrypted Virtualization (SEV) series focuses on the > changes required in a guest OS for SEV support. > > When SEV is active, the memory content of guest OS will be transparently > encrypted with a key unique to the guest VM. > > SEV guests have concept of private and shared memory. Private memory is > encrypted with the guest-specific key, while shared memory may be encrypted with > hypervisor key. Certain type of memory (namely insruction pages and guest page > tables) are always treated as private. Due to security reasons all DMA > operations inside the guest must be performed on shared memory. > > The SEV feature is enabled by the hypervisor, and guest can identify it through > CPUID function and the 0xc0010131 (F17H_SEV) MSR. When enabled, page table > entries will determine how memory is accessed. If a page table entry has the > memory encryption mask set, then that memory will be accessed using > guest-specific key. Certain memory (instruction pages, page tables) will always > be accessed using guest-specific key. > > This patch series builds upon the Secure Memory Encryption (SME) feature. Unlike > SME, when SEV is enabled, all the data (e.g EFI, kernel, initrd, etc) will have > been placed into memory as encrypted by the guest BIOS. > > The approach that this patch series takes is to encrypt everything possible > starting early in the boot. Since the DMA operations inside guest must be > performed on shared memory hence it uses SW-IOTLB to complete the DMA operations. > > The following links provide additional details: > > AMD Memory Encryption whitepaper: > http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf > > AMD64 Architecture Programmer's Manual: > http://support.amd.com/TechDocs/24593.pdf > SME is section 7.10 > SEV is section 15.34 > > Secure Encrypted Virutualization Key Management: > http://support.amd.com/TechDocs/55766_SEV-KM API_Specification.pdf > > KVM Forum Presentation: > http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf > > SEV Guest BIOS support: > SEV support has been accepted into EDKII/OVMF BIOS > https://github.com/tianocore/edk2/commits/master > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxx> > Cc: Andy Lutomirski <luto@xxxxxxxxxx> > Cc: Tom Lendacky <thomas.lendacky@xxxxxxx> > Cc: Brijesh Singh <brijesh.singh@xxxxxxx> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: "Radim KrĠmář" <rkrcmar@xxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: x86@xxxxxxxxxx > > --- > This series is based on tip/master commit : 7ffee292ddca (Merge branch 'x86/urgent') > > Complete git tree is available: https://github.com/codomania/tip/tree/sev-v7-p1 > > Changes since v6: > * include jump_label.h to fix the build error seen with one of the randconfig > > Changes since v5: > * enhance early_set_memory_decrypted() to do memory contents encrypt/decrypt in > addition to C bit changes. > > Changes since v4: > * rename per-CPU define to DEFINE_PER_CPU_DECRYPTED > * add more comments in per-CPU section definition > * rename __sev_active() to sev_key_active() to use more obivious naming > * changes to address v4 feedbacks > > Changes since v3: > * use static key to branch the unrolling of rep ins/outs when SEV is active > * simplify the memory encryption detection logic > * rename per-cpu define to DEFINE_PER_CPU_UNENCRYPTED > * simplfy the logic to map per-cpu as unencrypted > * changes to address v3 feedbacks > > Changes since v2: > * add documentation > * update early_set_memory_* to use kernel_physical_mapping_init() > to split larger page into smaller (recommended by Boris) > * changes to address v2 feedback > * drop hypervisor specific patches, those patches will be included in part 2 > > Brijesh Singh (5): > Documentation/x86: Add AMD Secure Encrypted Virtualization (SEV) > description > x86: Add support for changing memory encryption attribute in early > boot > percpu: Introduce DEFINE_PER_CPU_DECRYPTED > X86/KVM: Decrypt shared per-cpu variables when SEV is active > X86/KVM: Clear encryption attribute when SEV is active > > Tom Lendacky (12): > x86/mm: Add Secure Encrypted Virtualization (SEV) support > x86/mm: Don't attempt to encrypt initrd under SEV > x86/realmode: Don't decrypt trampoline area under SEV > x86/mm: Use encrypted access of boot related data with SEV > x86/mm: Include SEV for encryption memory attribute changes > x86/efi: Access EFI data as encrypted when SEV is active > resource: Consolidate resource walking code > resource: Provide resource struct in resource walk callback > x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory > pages > x86/mm: Add DMA support for SEV memory encryption > x86/boot: Add early boot support when running with SEV active > x86/io: Unroll string I/O when SEV is active > > Documentation/x86/amd-memory-encryption.txt | 30 ++- > arch/powerpc/kernel/machine_kexec_file_64.c | 12 +- > arch/x86/boot/compressed/Makefile | 1 + > arch/x86/boot/compressed/head_64.S | 16 ++ > arch/x86/boot/compressed/mem_encrypt.S | 120 +++++++++++ > arch/x86/boot/compressed/misc.h | 2 + > arch/x86/boot/compressed/pagetable.c | 8 +- > arch/x86/entry/vdso/vma.c | 5 +- > arch/x86/include/asm/io.h | 43 +++- > arch/x86/include/asm/mem_encrypt.h | 14 ++ > arch/x86/include/asm/msr-index.h | 3 + > arch/x86/include/uapi/asm/kvm_para.h | 1 - > arch/x86/kernel/crash.c | 18 +- > arch/x86/kernel/kvm.c | 40 +++- > arch/x86/kernel/kvmclock.c | 65 +++++- > arch/x86/kernel/pmem.c | 2 +- > arch/x86/kernel/setup.c | 6 +- > arch/x86/mm/ioremap.c | 123 +++++++++--- > arch/x86/mm/mem_encrypt.c | 300 +++++++++++++++++++++++++++- > arch/x86/mm/pageattr.c | 4 +- > arch/x86/platform/efi/efi_64.c | 16 +- > arch/x86/realmode/init.c | 5 +- > include/asm-generic/vmlinux.lds.h | 19 ++ > include/linux/ioport.h | 7 +- > include/linux/kexec.h | 2 +- > include/linux/mem_encrypt.h | 7 +- > include/linux/percpu-defs.h | 15 ++ > kernel/kexec_file.c | 5 +- > kernel/resource.c | 76 ++++--- > lib/swiotlb.c | 5 +- > 30 files changed, 847 insertions(+), 123 deletions(-) > create mode 100644 arch/x86/boot/compressed/mem_encrypt.S > > -- > 2.9.5 >
