diff options
| -rw-r--r-- | Documentation/virt/kvm/x86/amd-memory-encryption.rst | 40 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/kvm.h | 9 | ||||
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 53 |
3 files changed, 92 insertions, 10 deletions
diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index 2ea648e4c97a..3381556d596d 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -76,15 +76,49 @@ are defined in ``<linux/psp-dev.h>``. KVM implements the following commands to support common lifecycle events of SEV guests, such as launching, running, snapshotting, migrating and decommissioning. -1. KVM_SEV_INIT ---------------- +1. KVM_SEV_INIT2 +---------------- -The KVM_SEV_INIT command is used by the hypervisor to initialize the SEV platform +The KVM_SEV_INIT2 command is used by the hypervisor to initialize the SEV platform context. In a typical workflow, this command should be the first command issued. +For this command to be accepted, either KVM_X86_SEV_VM or KVM_X86_SEV_ES_VM +must have been passed to the KVM_CREATE_VM ioctl. A virtual machine created +with those machine types in turn cannot be run until KVM_SEV_INIT2 is invoked. + +Parameters: struct kvm_sev_init (in) Returns: 0 on success, -negative on error +:: + + struct kvm_sev_init { + __u64 vmsa_features; /* initial value of features field in VMSA */ + __u32 flags; /* must be 0 */ + __u32 pad[9]; + }; + +It is an error if the hypervisor does not support any of the bits that +are set in ``flags`` or ``vmsa_features``. ``vmsa_features`` must be +0 for SEV virtual machines, as they do not have a VMSA. + +This command replaces the deprecated KVM_SEV_INIT and KVM_SEV_ES_INIT commands. +The commands did not have any parameters (the ```data``` field was unused) and +only work for the KVM_X86_DEFAULT_VM machine type (0). + +They behave as if: + +* the VM type is KVM_X86_SEV_VM for KVM_SEV_INIT, or KVM_X86_SEV_ES_VM for + KVM_SEV_ES_INIT + +* the ``flags`` and ``vmsa_features`` fields of ``struct kvm_sev_init`` are + set to zero + +If the ``KVM_X86_SEV_VMSA_FEATURES`` attribute does not exist, the hypervisor only +supports KVM_SEV_INIT and KVM_SEV_ES_INIT. In that case, note that KVM_SEV_ES_INIT +might set the debug swap VMSA feature (bit 5) depending on the value of the +``debug_swap`` parameter of ``kvm-amd.ko``. + 2. KVM_SEV_LAUNCH_START ----------------------- diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index ab609adacb11..72ad5ace118d 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -694,6 +694,9 @@ enum sev_cmd_id { /* Guest Migration Extension */ KVM_SEV_SEND_CANCEL, + /* Second time is the charm; improved versions of the above ioctls. */ + KVM_SEV_INIT2, + KVM_SEV_NR_MAX, }; @@ -705,6 +708,12 @@ struct kvm_sev_cmd { __u32 sev_fd; }; +struct kvm_sev_init { + __u64 vmsa_features; + __u32 flags; + __u32 pad[9]; +}; + struct kvm_sev_launch_start { __u32 handle; __u32 policy; diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 3517d6736c93..2f20270be93b 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -243,27 +243,31 @@ static void sev_unbind_asid(struct kvm *kvm, unsigned int handle) sev_decommission(handle); } -static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) +static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp, + struct kvm_sev_init *data, + unsigned long vm_type) { struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; struct sev_platform_init_args init_args = {0}; + bool es_active = vm_type != KVM_X86_SEV_VM; + u64 valid_vmsa_features = es_active ? sev_supported_vmsa_features : 0; int ret; if (kvm->created_vcpus) return -EINVAL; - if (kvm->arch.vm_type != KVM_X86_DEFAULT_VM) + if (data->flags) + return -EINVAL; + + if (data->vmsa_features & ~valid_vmsa_features) return -EINVAL; if (unlikely(sev->active)) return -EINVAL; sev->active = true; - sev->es_active = argp->id == KVM_SEV_ES_INIT; - sev->vmsa_features = sev_supported_vmsa_features; - if (sev_supported_vmsa_features) - pr_warn_once("Enabling DebugSwap with KVM_SEV_ES_INIT. " - "This will not work starting with Linux 6.10\n"); + sev->es_active = es_active; + sev->vmsa_features = data->vmsa_features; ret = sev_asid_new(sev); if (ret) @@ -293,6 +297,38 @@ e_no_asid: return ret; } +static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct kvm_sev_init data = { + .vmsa_features = 0, + }; + unsigned long vm_type; + + if (kvm->arch.vm_type != KVM_X86_DEFAULT_VM) + return -EINVAL; + + vm_type = (argp->id == KVM_SEV_INIT ? KVM_X86_SEV_VM : KVM_X86_SEV_ES_VM); + return __sev_guest_init(kvm, argp, &data, vm_type); +} + +static int sev_guest_init2(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct kvm_sev_init data; + + if (!sev->need_init) + return -EINVAL; + + if (kvm->arch.vm_type != KVM_X86_SEV_VM && + kvm->arch.vm_type != KVM_X86_SEV_ES_VM) + return -EINVAL; + + if (copy_from_user(&data, u64_to_user_ptr(argp->data), sizeof(data))) + return -EFAULT; + + return __sev_guest_init(kvm, argp, &data, kvm->arch.vm_type); +} + static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error) { unsigned int asid = sev_get_asid(kvm); @@ -1960,6 +1996,9 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) case KVM_SEV_INIT: r = sev_guest_init(kvm, &sev_cmd); break; + case KVM_SEV_INIT2: + r = sev_guest_init2(kvm, &sev_cmd); + break; case KVM_SEV_LAUNCH_START: r = sev_launch_start(kvm, &sev_cmd); break; |