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Diffstat (limited to 'Documentation/virt/kvm/x86/amd-memory-encryption.rst')
| -rw-r--r-- | Documentation/virt/kvm/x86/amd-memory-encryption.rst | 42 |
1 files changed, 24 insertions, 18 deletions
diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index 995780088e..84335d119f 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -46,21 +46,16 @@ SEV hardware uses ASIDs to associate a memory encryption key with a VM. Hence, the ASID for the SEV-enabled guests must be from 1 to a maximum value defined in the CPUID 0x8000001f[ecx] field. -SEV Key Management -================== +The KVM_MEMORY_ENCRYPT_OP ioctl +=============================== -The SEV guest key management is handled by a separate processor called the AMD -Secure Processor (AMD-SP). Firmware running inside the AMD-SP provides a secure -key management interface to perform common hypervisor activities such as -encrypting bootstrap code, snapshot, migrating and debugging the guest. For more -information, see the SEV Key Management spec [api-spec]_ - -The main ioctl to access SEV is KVM_MEMORY_ENCRYPT_OP. If the argument -to KVM_MEMORY_ENCRYPT_OP is NULL, the ioctl returns 0 if SEV is enabled -and ``ENOTTY`` if it is disabled (on some older versions of Linux, -the ioctl runs normally even with a NULL argument, and therefore will -likely return ``EFAULT``). If non-NULL, the argument to KVM_MEMORY_ENCRYPT_OP -must be a struct kvm_sev_cmd:: +The main ioctl to access SEV is KVM_MEMORY_ENCRYPT_OP, which operates on +the VM file descriptor. If the argument to KVM_MEMORY_ENCRYPT_OP is NULL, +the ioctl returns 0 if SEV is enabled and ``ENOTTY`` if it is disabled +(on some older versions of Linux, the ioctl tries to run normally even +with a NULL argument, and therefore will likely return ``EFAULT`` instead +of zero if SEV is enabled). If non-NULL, the argument to +KVM_MEMORY_ENCRYPT_OP must be a struct kvm_sev_cmd:: struct kvm_sev_cmd { __u32 id; @@ -87,10 +82,6 @@ guests, such as launching, running, snapshotting, migrating and decommissioning. The KVM_SEV_INIT command is used by the hypervisor to initialize the SEV platform context. In a typical workflow, this command should be the first command issued. -The firmware can be initialized either by using its own non-volatile storage or -the OS can manage the NV storage for the firmware using the module parameter -``init_ex_path``. If the file specified by ``init_ex_path`` does not exist or -is invalid, the OS will create or override the file with output from PSP. Returns: 0 on success, -negative on error @@ -434,6 +425,21 @@ issued by the hypervisor to make the guest ready for execution. Returns: 0 on success, -negative on error +Firmware Management +=================== + +The SEV guest key management is handled by a separate processor called the AMD +Secure Processor (AMD-SP). Firmware running inside the AMD-SP provides a secure +key management interface to perform common hypervisor activities such as +encrypting bootstrap code, snapshot, migrating and debugging the guest. For more +information, see the SEV Key Management spec [api-spec]_ + +The AMD-SP firmware can be initialized either by using its own non-volatile +storage or the OS can manage the NV storage for the firmware using +parameter ``init_ex_path`` of the ``ccp`` module. If the file specified +by ``init_ex_path`` does not exist or is invalid, the OS will create or +override the file with PSP non-volatile storage. + References ========== |