On Thu, Apr 1, 2021 at 6:45 PM Steve Rutherford <srutherford@xxxxxxxxxx> wrote:
>
> After completion of SEND_START, but before SEND_FINISH, the source VMM can
> issue the SEND_CANCEL command to stop a migration. This is necessary so
> that a cancelled migration can restart with a new target later.
>
> Signed-off-by: Steve Rutherford <srutherford@xxxxxxxxxx>
> ---
> .../virt/kvm/amd-memory-encryption.rst | 9 +++++++
> arch/x86/kvm/svm/sev.c | 24 +++++++++++++++++++
> include/linux/psp-sev.h | 10 ++++++++
> include/uapi/linux/kvm.h | 2 ++
> 4 files changed, 45 insertions(+)
>
> diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
> index 469a6308765b1..9e018a3eec03b 100644
> --- a/Documentation/virt/kvm/amd-memory-encryption.rst
> +++ b/Documentation/virt/kvm/amd-memory-encryption.rst
> @@ -284,6 +284,15 @@ Returns: 0 on success, -negative on error
> __u32 len;
> };
>
> +16. KVM_SEV_SEND_CANCEL
> +------------------------
> +
> +After completion of SEND_START, but before SEND_FINISH, the source VMM can issue the
> +SEND_CANCEL command to stop a migration. This is necessary so that a cancelled
> +migration can restart with a new target later.
> +
> +Returns: 0 on success, -negative on error
> +
> References
> ==========
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 83e00e5245136..88e72102cb900 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1110,6 +1110,27 @@ static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
> return ret;
> }
>
> +static int sev_send_cancel(struct kvm *kvm, struct kvm_sev_cmd *argp)
> +{
> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> + struct sev_data_send_cancel *data;
> + int ret;
> +
> + if (!sev_guest(kvm))
> + return -ENOTTY;
> +
> + data = kzalloc(sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->handle = sev->handle;
> + ret = sev_issue_cmd(kvm, SEV_CMD_SEND_CANCEL, data, &argp->error);
> +
> + kfree(data);
> + return ret;
> +}
> +
> +
> int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> {
> struct kvm_sev_cmd sev_cmd;
> @@ -1163,6 +1184,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> case KVM_SEV_GET_ATTESTATION_REPORT:
> r = sev_get_attestation_report(kvm, &sev_cmd);
> break;
> + case KVM_SEV_SEND_CANCEL:
> + r = sev_send_cancel(kvm, &sev_cmd);
> + break;
> default:
> r = -EINVAL;
> goto out;
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index b801ead1e2bb5..74f2babffc574 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -73,6 +73,7 @@ enum sev_cmd {
> SEV_CMD_SEND_UPDATE_DATA = 0x041,
> SEV_CMD_SEND_UPDATE_VMSA = 0x042,
> SEV_CMD_SEND_FINISH = 0x043,
> + SEV_CMD_SEND_CANCEL = 0x044,
>
> /* Guest migration commands (incoming) */
> SEV_CMD_RECEIVE_START = 0x050,
> @@ -392,6 +393,15 @@ struct sev_data_send_finish {
> u32 handle; /* In */
> } __packed;
>
> +/**
> + * struct sev_data_send_cancel - SEND_CANCEL command parameters
> + *
> + * @handle: handle of the VM to process
> + */
> +struct sev_data_send_cancel {
> + u32 handle; /* In */
> +} __packed;
> +
> /**
> * struct sev_data_receive_start - RECEIVE_START command parameters
> *
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index f6afee209620d..707469b6b7072 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1671,6 +1671,8 @@ enum sev_cmd_id {
> KVM_SEV_CERT_EXPORT,
> /* Attestation report */
> KVM_SEV_GET_ATTESTATION_REPORT,
> + /* Guest Migration Extension */
> + KVM_SEV_SEND_CANCEL,
>
> KVM_SEV_NR_MAX,
> };
> --
> 2.31.0.208.g409f899ff0-goog
>
Reviewed-by: Nathan Tempelman <natet@xxxxxxxxxx>
