2021-04-02 01:48:44

by Steve Rutherford

[permalink] [raw]
Subject: [PATCH] KVM: SVM: Add support for KVM_SEV_SEND_CANCEL command

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 <[email protected]>
---
.../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


2021-04-08 22:05:07

by Nathan Tempelman

[permalink] [raw]
Subject: Re: [PATCH] KVM: SVM: Add support for KVM_SEV_SEND_CANCEL command

On Thu, Apr 1, 2021 at 6:45 PM Steve Rutherford <[email protected]> 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 <[email protected]>
> ---
> .../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 <[email protected]>

2021-04-08 22:28:02

by Brijesh Singh

[permalink] [raw]
Subject: Re: [PATCH] KVM: SVM: Add support for KVM_SEV_SEND_CANCEL command


On 4/1/21 8:44 PM, Steve Rutherford 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 <[email protected]>
> ---
> .../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(+)


Can we add a new case statement in sev_cmd_buffer_len()
[drivers/crypto/ccp/sev-dev.c] for this command ? I understand that the
command just contains the handle. I have found dyndbg very helpful. If
the command is not added in the sev_cmd_buffer_len() then we don't dump
the command buffer.

With that fixed.

Reviewed-by: Brijesh Singh <[email protected]>


2021-04-09 00:50:41

by Steve Rutherford

[permalink] [raw]
Subject: Re: [PATCH] KVM: SVM: Add support for KVM_SEV_SEND_CANCEL command

On Thu, Apr 8, 2021 at 3:27 PM Brijesh Singh <[email protected]> wrote:
>
>
> On 4/1/21 8:44 PM, Steve Rutherford 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 <[email protected]>
> > ---
> > .../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(+)
>
>
> Can we add a new case statement in sev_cmd_buffer_len()
> [drivers/crypto/ccp/sev-dev.c] for this command ? I understand that the
> command just contains the handle. I have found dyndbg very helpful. If
> the command is not added in the sev_cmd_buffer_len() then we don't dump
> the command buffer.
>
> With that fixed.
>
> Reviewed-by: Brijesh Singh <[email protected]>

Nice catch, will follow-up shortly.


Steve