diff mbox series

[v7,01/18] KVM: SVM: Add KVM_SEV SEND_START command

Message ID 6473e5803d8c47d9b207810e8015c3066c39f17d.1588234824.git.ashish.kalra@amd.com (mailing list archive)
State New, archived
Headers show
Series Add AMD SEV guest live migration support | expand

Commit Message

Kalra, Ashish April 30, 2020, 8:40 a.m. UTC
From: Brijesh Singh <Brijesh.Singh@amd.com>

The command is used to create an outgoing SEV guest encryption context.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 .../virt/kvm/amd-memory-encryption.rst        |  27 ++++
 arch/x86/kvm/svm/sev.c                        | 125 ++++++++++++++++++
 include/linux/psp-sev.h                       |   8 +-
 include/uapi/linux/kvm.h                      |  12 ++
 4 files changed, 168 insertions(+), 4 deletions(-)

Comments

Venu Busireddy May 4, 2020, 9:07 p.m. UTC | #1
On 2020-04-30 08:40:34 +0000, Ashish Kalra wrote:
> From: Brijesh Singh <Brijesh.Singh@amd.com>
> 
> The command is used to create an outgoing SEV guest encryption context.
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: "Radim Krčmář" <rkrcmar@redhat.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: x86@kernel.org
> Cc: kvm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Reviewed-by: Steve Rutherford <srutherford@google.com>
> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
>  .../virt/kvm/amd-memory-encryption.rst        |  27 ++++
>  arch/x86/kvm/svm/sev.c                        | 125 ++++++++++++++++++
>  include/linux/psp-sev.h                       |   8 +-
>  include/uapi/linux/kvm.h                      |  12 ++
>  4 files changed, 168 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
> index c3129b9ba5cb..4fd34fc5c7a7 100644
> --- a/Documentation/virt/kvm/amd-memory-encryption.rst
> +++ b/Documentation/virt/kvm/amd-memory-encryption.rst
> @@ -263,6 +263,33 @@ Returns: 0 on success, -negative on error
>                  __u32 trans_len;
>          };
>  
> +10. KVM_SEV_SEND_START
> +----------------------
> +
> +The KVM_SEV_SEND_START command can be used by the hypervisor to create an
> +outgoing guest encryption context.
> +
> +Parameters (in): struct kvm_sev_send_start
> +
> +Returns: 0 on success, -negative on error
> +
> +::
> +        struct kvm_sev_send_start {
> +                __u32 policy;                 /* guest policy */
> +
> +                __u64 pdh_cert_uaddr;         /* platform Diffie-Hellman certificate */
> +                __u32 pdh_cert_len;
> +
> +                __u64 plat_certs_uadr;        /* platform certificate chain */

Can this be changed as mentioned in the previous review
(https://lore.kernel.org/kvm/20200402062726.GA647295@vbusired-dt/)?

> +                __u32 plat_certs_len;
> +
> +                __u64 amd_certs_uaddr;        /* AMD certificate */
> +                __u32 amd_cert_len;

Can this be changed as mentioned in the previous review
(https://lore.kernel.org/kvm/20200402062726.GA647295@vbusired-dt/)?

> +
> +                __u64 session_uaddr;          /* Guest session information */
> +                __u32 session_len;
> +        };
> +
>  References
>  ==========
>  
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index cf912b4aaba8..5a15b43b4349 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -913,6 +913,128 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
>  	return ret;
>  }
>  
> +/* Userspace wants to query session length. */
> +static int
> +__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
> +				      struct kvm_sev_send_start *params)
> +{
> +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> +	struct sev_data_send_start *data;
> +	int ret;
> +
> +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> +	if (data == NULL)
> +		return -ENOMEM;
> +
> +	data->handle = sev->handle;
> +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> +
> +	params->session_len = data->session_len;
> +	if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
> +				sizeof(struct kvm_sev_send_start)))
> +		ret = -EFAULT;
> +
> +	kfree(data);
> +	return ret;
> +}
> +
> +static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
> +{
> +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> +	struct sev_data_send_start *data;
> +	struct kvm_sev_send_start params;
> +	void *amd_certs, *session_data;
> +	void *pdh_cert, *plat_certs;
> +	int ret;
> +
> +	if (!sev_guest(kvm))
> +		return -ENOTTY;
> +
> +	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
> +				sizeof(struct kvm_sev_send_start)))
> +		return -EFAULT;
> +
> +	/* if session_len is zero, userspace wants to query the session length */
> +	if (!params.session_len)
> +		return __sev_send_start_query_session_length(kvm, argp,
> +				&params);
> +
> +	/* some sanity checks */
> +	if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
> +	    !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
> +		return -EINVAL;
> +
> +	/* allocate the memory to hold the session data blob */
> +	session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
> +	if (!session_data)
> +		return -ENOMEM;
> +
> +	/* copy the certificate blobs from userspace */
> +	pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr,
> +				params.pdh_cert_len);
> +	if (IS_ERR(pdh_cert)) {
> +		ret = PTR_ERR(pdh_cert);
> +		goto e_free_session;
> +	}
> +
> +	plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
> +				params.plat_certs_len);
> +	if (IS_ERR(plat_certs)) {
> +		ret = PTR_ERR(plat_certs);
> +		goto e_free_pdh;
> +	}
> +
> +	amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
> +				params.amd_certs_len);
> +	if (IS_ERR(amd_certs)) {
> +		ret = PTR_ERR(amd_certs);
> +		goto e_free_plat_cert;
> +	}
> +
> +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> +	if (data == NULL) {
> +		ret = -ENOMEM;
> +		goto e_free_amd_cert;
> +	}
> +
> +	/* populate the FW SEND_START field with system physical address */
> +	data->pdh_cert_address = __psp_pa(pdh_cert);
> +	data->pdh_cert_len = params.pdh_cert_len;
> +	data->plat_certs_address = __psp_pa(plat_certs);
> +	data->plat_certs_len = params.plat_certs_len;
> +	data->amd_certs_address = __psp_pa(amd_certs);
> +	data->amd_certs_len = params.amd_certs_len;
> +	data->session_address = __psp_pa(session_data);
> +	data->session_len = params.session_len;
> +	data->handle = sev->handle;
> +

Can the following code be changed as acknowledged in
https://lore.kernel.org/kvm/f715bf99-0158-4d5f-77f3-b27743db3c59@amd.com/?

> +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> +
> +	if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
> +			session_data, params.session_len)) {
> +		ret = -EFAULT;
> +		goto e_free;
> +	}
> +
> +	params.policy = data->policy;
> +	params.session_len = data->session_len;
> +	if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
> +				sizeof(struct kvm_sev_send_start)))
> +		ret = -EFAULT;
> +
> +e_free:
> +	kfree(data);
> +e_free_amd_cert:
> +	kfree(amd_certs);
> +e_free_plat_cert:
> +	kfree(plat_certs);
> +e_free_pdh:
> +	kfree(pdh_cert);
> +e_free_session:
> +	kfree(session_data);
> +	return ret;
> +}
> +
>  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
>  {
>  	struct kvm_sev_cmd sev_cmd;
> @@ -957,6 +1079,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
>  	case KVM_SEV_LAUNCH_SECRET:
>  		r = sev_launch_secret(kvm, &sev_cmd);
>  		break;
> +	case KVM_SEV_SEND_START:
> +		r = sev_send_start(kvm, &sev_cmd);
> +		break;
>  	default:
>  		r = -EINVAL;
>  		goto out;
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index 5167bf2bfc75..9f63b9d48b63 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -323,11 +323,11 @@ struct sev_data_send_start {
>  	u64 pdh_cert_address;			/* In */
>  	u32 pdh_cert_len;			/* In */
>  	u32 reserved1;
> -	u64 plat_cert_address;			/* In */
> -	u32 plat_cert_len;			/* In */
> +	u64 plat_certs_address;			/* In */
> +	u32 plat_certs_len;			/* In */
>  	u32 reserved2;
> -	u64 amd_cert_address;			/* In */
> -	u32 amd_cert_len;			/* In */
> +	u64 amd_certs_address;			/* In */
> +	u32 amd_certs_len;			/* In */
>  	u32 reserved3;
>  	u64 session_address;			/* In */
>  	u32 session_len;			/* In/Out */
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 428c7dde6b4b..8827d43e2684 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1598,6 +1598,18 @@ struct kvm_sev_dbg {
>  	__u32 len;
>  };
>  
> +struct kvm_sev_send_start {
> +	__u32 policy;
> +	__u64 pdh_cert_uaddr;
> +	__u32 pdh_cert_len;
> +	__u64 plat_certs_uaddr;
> +	__u32 plat_certs_len;
> +	__u64 amd_certs_uaddr;
> +	__u32 amd_certs_len;
> +	__u64 session_uaddr;
> +	__u32 session_len;
> +};
> +
>  #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
>  #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
>  #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)
> -- 
> 2.17.1
>
Kalra, Ashish May 4, 2020, 10:36 p.m. UTC | #2
On Mon, May 04, 2020 at 04:07:17PM -0500, Venu Busireddy wrote:
> On 2020-04-30 08:40:34 +0000, Ashish Kalra wrote:
> > From: Brijesh Singh <Brijesh.Singh@amd.com>
> > 
> > The command is used to create an outgoing SEV guest encryption context.
> > 
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: "H. Peter Anvin" <hpa@zytor.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Cc: "Radim Krčmář" <rkrcmar@redhat.com>
> > Cc: Joerg Roedel <joro@8bytes.org>
> > Cc: Borislav Petkov <bp@suse.de>
> > Cc: Tom Lendacky <thomas.lendacky@amd.com>
> > Cc: x86@kernel.org
> > Cc: kvm@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > Reviewed-by: Steve Rutherford <srutherford@google.com>
> > Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
> > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> > ---
> >  .../virt/kvm/amd-memory-encryption.rst        |  27 ++++
> >  arch/x86/kvm/svm/sev.c                        | 125 ++++++++++++++++++
> >  include/linux/psp-sev.h                       |   8 +-
> >  include/uapi/linux/kvm.h                      |  12 ++
> >  4 files changed, 168 insertions(+), 4 deletions(-)
> > 
> > diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
> > index c3129b9ba5cb..4fd34fc5c7a7 100644
> > --- a/Documentation/virt/kvm/amd-memory-encryption.rst
> > +++ b/Documentation/virt/kvm/amd-memory-encryption.rst
> > @@ -263,6 +263,33 @@ Returns: 0 on success, -negative on error
> >                  __u32 trans_len;
> >          };
> >  
> > +10. KVM_SEV_SEND_START
> > +----------------------
> > +
> > +The KVM_SEV_SEND_START command can be used by the hypervisor to create an
> > +outgoing guest encryption context.
> > +
> > +Parameters (in): struct kvm_sev_send_start
> > +
> > +Returns: 0 on success, -negative on error
> > +
> > +::
> > +        struct kvm_sev_send_start {
> > +                __u32 policy;                 /* guest policy */
> > +
> > +                __u64 pdh_cert_uaddr;         /* platform Diffie-Hellman certificate */
> > +                __u32 pdh_cert_len;
> > +
> > +                __u64 plat_certs_uadr;        /* platform certificate chain */
> 
> Can this be changed as mentioned in the previous review
> (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2F20200402062726.GA647295%40vbusired-dt%2F&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7C5ea8d5ae78814a01618908d7f06f7667%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242233846313842&amp;sdata=qfxRdCY3A1Tox%2FMI%2FQLmUcvIxbfL%2BwoR2fzfQa1FVkA%3D&amp;reserved=0)?
> 
> > +                __u32 plat_certs_len;
> > +
> > +                __u64 amd_certs_uaddr;        /* AMD certificate */
> > +                __u32 amd_cert_len;
> 
> Can this be changed as mentioned in the previous review
> (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2F20200402062726.GA647295%40vbusired-dt%2F&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7C5ea8d5ae78814a01618908d7f06f7667%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242233846323835&amp;sdata=SMYG1m%2BT2KwNQ4Jed%2BJhsK6TQ7EYTKT16moEoZMTf7c%3D&amp;reserved=0)?
> 
> > +
> > +                __u64 session_uaddr;          /* Guest session information */
> > +                __u32 session_len;
> > +        };
> > +
> >  References
> >  ==========
> >  
> > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > index cf912b4aaba8..5a15b43b4349 100644
> > --- a/arch/x86/kvm/svm/sev.c
> > +++ b/arch/x86/kvm/svm/sev.c
> > @@ -913,6 +913,128 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
> >  	return ret;
> >  }
> >  
> > +/* Userspace wants to query session length. */
> > +static int
> > +__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
> > +				      struct kvm_sev_send_start *params)
> > +{
> > +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > +	struct sev_data_send_start *data;
> > +	int ret;
> > +
> > +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> > +	if (data == NULL)
> > +		return -ENOMEM;
> > +
> > +	data->handle = sev->handle;
> > +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> > +
> > +	params->session_len = data->session_len;
> > +	if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
> > +				sizeof(struct kvm_sev_send_start)))
> > +		ret = -EFAULT;
> > +
> > +	kfree(data);
> > +	return ret;
> > +}
> > +
> > +static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
> > +{
> > +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > +	struct sev_data_send_start *data;
> > +	struct kvm_sev_send_start params;
> > +	void *amd_certs, *session_data;
> > +	void *pdh_cert, *plat_certs;
> > +	int ret;
> > +
> > +	if (!sev_guest(kvm))
> > +		return -ENOTTY;
> > +
> > +	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
> > +				sizeof(struct kvm_sev_send_start)))
> > +		return -EFAULT;
> > +
> > +	/* if session_len is zero, userspace wants to query the session length */
> > +	if (!params.session_len)
> > +		return __sev_send_start_query_session_length(kvm, argp,
> > +				&params);
> > +
> > +	/* some sanity checks */
> > +	if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
> > +	    !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
> > +		return -EINVAL;
> > +
> > +	/* allocate the memory to hold the session data blob */
> > +	session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
> > +	if (!session_data)
> > +		return -ENOMEM;
> > +
> > +	/* copy the certificate blobs from userspace */
> > +	pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr,
> > +				params.pdh_cert_len);
> > +	if (IS_ERR(pdh_cert)) {
> > +		ret = PTR_ERR(pdh_cert);
> > +		goto e_free_session;
> > +	}
> > +
> > +	plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
> > +				params.plat_certs_len);
> > +	if (IS_ERR(plat_certs)) {
> > +		ret = PTR_ERR(plat_certs);
> > +		goto e_free_pdh;
> > +	}
> > +
> > +	amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
> > +				params.amd_certs_len);
> > +	if (IS_ERR(amd_certs)) {
> > +		ret = PTR_ERR(amd_certs);
> > +		goto e_free_plat_cert;
> > +	}
> > +
> > +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> > +	if (data == NULL) {
> > +		ret = -ENOMEM;
> > +		goto e_free_amd_cert;
> > +	}
> > +
> > +	/* populate the FW SEND_START field with system physical address */
> > +	data->pdh_cert_address = __psp_pa(pdh_cert);
> > +	data->pdh_cert_len = params.pdh_cert_len;
> > +	data->plat_certs_address = __psp_pa(plat_certs);
> > +	data->plat_certs_len = params.plat_certs_len;
> > +	data->amd_certs_address = __psp_pa(amd_certs);
> > +	data->amd_certs_len = params.amd_certs_len;
> > +	data->session_address = __psp_pa(session_data);
> > +	data->session_len = params.session_len;
> > +	data->handle = sev->handle;
> > +
> 
> Can the following code be changed as acknowledged in
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2Ff715bf99-0158-4d5f-77f3-b27743db3c59%40amd.com%2F&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7C5ea8d5ae78814a01618908d7f06f7667%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242233846323835&amp;sdata=5hbjsP%2Btxt2rdv2PtIc%2BV8cAwKUNsRdtiRglDupYXzs%3D&amp;reserved=0?
> 

I believe that this has been already addressed as discussed :

Ah, so the main issue is we should not be going to e_free on error. If
session_len is less than the expected len then FW will return an error.
In the case of an error we can skip copying the session_data into
userspace buffer but we still need to pass the session_len and policy
back to the userspace.

So this patch is still returning session_len and policy back to user
in case of error : ( as the code below shows )

if (!ret && copy_to_user((void
__user*)(uintptr_t)params.session_uaddr,...

Thanks,
Ashish

> > +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> > +
> > +	if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
> > +			session_data, params.session_len)) {
> > +		ret = -EFAULT;
> > +		goto e_free;
> > +	}
> > +
> > +	params.policy = data->policy;
> > +	params.session_len = data->session_len;
> > +	if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
> > +				sizeof(struct kvm_sev_send_start)))
> > +		ret = -EFAULT;
> > +
> > +e_free:
> > +	kfree(data);
> > +e_free_amd_cert:
> > +	kfree(amd_certs);
> > +e_free_plat_cert:
> > +	kfree(plat_certs);
> > +e_free_pdh:
> > +	kfree(pdh_cert);
> > +e_free_session:
> > +	kfree(session_data);
> > +	return ret;
> > +}
> > +
> >  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> >  {
> >  	struct kvm_sev_cmd sev_cmd;
> > @@ -957,6 +1079,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> >  	case KVM_SEV_LAUNCH_SECRET:
> >  		r = sev_launch_secret(kvm, &sev_cmd);
> >  		break;
> > +	case KVM_SEV_SEND_START:
> > +		r = sev_send_start(kvm, &sev_cmd);
> > +		break;
> >  	default:
> >  		r = -EINVAL;
> >  		goto out;
> > diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> > index 5167bf2bfc75..9f63b9d48b63 100644
> > --- a/include/linux/psp-sev.h
> > +++ b/include/linux/psp-sev.h
> > @@ -323,11 +323,11 @@ struct sev_data_send_start {
> >  	u64 pdh_cert_address;			/* In */
> >  	u32 pdh_cert_len;			/* In */
> >  	u32 reserved1;
> > -	u64 plat_cert_address;			/* In */
> > -	u32 plat_cert_len;			/* In */
> > +	u64 plat_certs_address;			/* In */
> > +	u32 plat_certs_len;			/* In */
> >  	u32 reserved2;
> > -	u64 amd_cert_address;			/* In */
> > -	u32 amd_cert_len;			/* In */
> > +	u64 amd_certs_address;			/* In */
> > +	u32 amd_certs_len;			/* In */
> >  	u32 reserved3;
> >  	u64 session_address;			/* In */
> >  	u32 session_len;			/* In/Out */
> > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > index 428c7dde6b4b..8827d43e2684 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -1598,6 +1598,18 @@ struct kvm_sev_dbg {
> >  	__u32 len;
> >  };
> >  
> > +struct kvm_sev_send_start {
> > +	__u32 policy;
> > +	__u64 pdh_cert_uaddr;
> > +	__u32 pdh_cert_len;
> > +	__u64 plat_certs_uaddr;
> > +	__u32 plat_certs_len;
> > +	__u64 amd_certs_uaddr;
> > +	__u32 amd_certs_len;
> > +	__u64 session_uaddr;
> > +	__u32 session_len;
> > +};
> > +
> >  #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
> >  #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
> >  #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)
> > -- 
> > 2.17.1
> >
Venu Busireddy May 4, 2020, 11:10 p.m. UTC | #3
On 2020-05-04 22:36:37 +0000, Ashish Kalra wrote:
> On Mon, May 04, 2020 at 04:07:17PM -0500, Venu Busireddy wrote:
> > On 2020-04-30 08:40:34 +0000, Ashish Kalra wrote:
> > > From: Brijesh Singh <Brijesh.Singh@amd.com>
> > > 
> > > The command is used to create an outgoing SEV guest encryption context.
> > > 
> > > Cc: Thomas Gleixner <tglx@linutronix.de>
> > > Cc: Ingo Molnar <mingo@redhat.com>
> > > Cc: "H. Peter Anvin" <hpa@zytor.com>
> > > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > > Cc: "Radim Krčmář" <rkrcmar@redhat.com>
> > > Cc: Joerg Roedel <joro@8bytes.org>
> > > Cc: Borislav Petkov <bp@suse.de>
> > > Cc: Tom Lendacky <thomas.lendacky@amd.com>
> > > Cc: x86@kernel.org
> > > Cc: kvm@vger.kernel.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Reviewed-by: Steve Rutherford <srutherford@google.com>
> > > Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
> > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> > > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> > > ---
> > >  .../virt/kvm/amd-memory-encryption.rst        |  27 ++++
> > >  arch/x86/kvm/svm/sev.c                        | 125 ++++++++++++++++++
> > >  include/linux/psp-sev.h                       |   8 +-
> > >  include/uapi/linux/kvm.h                      |  12 ++
> > >  4 files changed, 168 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
> > > index c3129b9ba5cb..4fd34fc5c7a7 100644
> > > --- a/Documentation/virt/kvm/amd-memory-encryption.rst
> > > +++ b/Documentation/virt/kvm/amd-memory-encryption.rst
> > > @@ -263,6 +263,33 @@ Returns: 0 on success, -negative on error
> > >                  __u32 trans_len;
> > >          };
> > >  
> > > +10. KVM_SEV_SEND_START
> > > +----------------------
> > > +
> > > +The KVM_SEV_SEND_START command can be used by the hypervisor to create an
> > > +outgoing guest encryption context.
> > > +
> > > +Parameters (in): struct kvm_sev_send_start
> > > +
> > > +Returns: 0 on success, -negative on error
> > > +
> > > +::
> > > +        struct kvm_sev_send_start {
> > > +                __u32 policy;                 /* guest policy */
> > > +
> > > +                __u64 pdh_cert_uaddr;         /* platform Diffie-Hellman certificate */
> > > +                __u32 pdh_cert_len;
> > > +
> > > +                __u64 plat_certs_uadr;        /* platform certificate chain */
> > 
> > Can this be changed as mentioned in the previous review
> > (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2F20200402062726.GA647295%40vbusired-dt%2F&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7C5ea8d5ae78814a01618908d7f06f7667%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242233846313842&amp;sdata=qfxRdCY3A1Tox%2FMI%2FQLmUcvIxbfL%2BwoR2fzfQa1FVkA%3D&amp;reserved=0)?
> > 
> > > +                __u32 plat_certs_len;
> > > +
> > > +                __u64 amd_certs_uaddr;        /* AMD certificate */
> > > +                __u32 amd_cert_len;
> > 
> > Can this be changed as mentioned in the previous review
> > (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2F20200402062726.GA647295%40vbusired-dt%2F&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7C5ea8d5ae78814a01618908d7f06f7667%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242233846323835&amp;sdata=SMYG1m%2BT2KwNQ4Jed%2BJhsK6TQ7EYTKT16moEoZMTf7c%3D&amp;reserved=0)?
> > 
> > > +
> > > +                __u64 session_uaddr;          /* Guest session information */
> > > +                __u32 session_len;
> > > +        };
> > > +
> > >  References
> > >  ==========
> > >  
> > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > > index cf912b4aaba8..5a15b43b4349 100644
> > > --- a/arch/x86/kvm/svm/sev.c
> > > +++ b/arch/x86/kvm/svm/sev.c
> > > @@ -913,6 +913,128 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
> > >  	return ret;
> > >  }
> > >  
> > > +/* Userspace wants to query session length. */
> > > +static int
> > > +__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
> > > +				      struct kvm_sev_send_start *params)
> > > +{
> > > +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > > +	struct sev_data_send_start *data;
> > > +	int ret;
> > > +
> > > +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> > > +	if (data == NULL)
> > > +		return -ENOMEM;
> > > +
> > > +	data->handle = sev->handle;
> > > +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> > > +
> > > +	params->session_len = data->session_len;
> > > +	if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
> > > +				sizeof(struct kvm_sev_send_start)))
> > > +		ret = -EFAULT;
> > > +
> > > +	kfree(data);
> > > +	return ret;
> > > +}
> > > +
> > > +static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
> > > +{
> > > +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > > +	struct sev_data_send_start *data;
> > > +	struct kvm_sev_send_start params;
> > > +	void *amd_certs, *session_data;
> > > +	void *pdh_cert, *plat_certs;
> > > +	int ret;
> > > +
> > > +	if (!sev_guest(kvm))
> > > +		return -ENOTTY;
> > > +
> > > +	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
> > > +				sizeof(struct kvm_sev_send_start)))
> > > +		return -EFAULT;
> > > +
> > > +	/* if session_len is zero, userspace wants to query the session length */
> > > +	if (!params.session_len)
> > > +		return __sev_send_start_query_session_length(kvm, argp,
> > > +				&params);
> > > +
> > > +	/* some sanity checks */
> > > +	if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
> > > +	    !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
> > > +		return -EINVAL;
> > > +
> > > +	/* allocate the memory to hold the session data blob */
> > > +	session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
> > > +	if (!session_data)
> > > +		return -ENOMEM;
> > > +
> > > +	/* copy the certificate blobs from userspace */
> > > +	pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr,
> > > +				params.pdh_cert_len);
> > > +	if (IS_ERR(pdh_cert)) {
> > > +		ret = PTR_ERR(pdh_cert);
> > > +		goto e_free_session;
> > > +	}
> > > +
> > > +	plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
> > > +				params.plat_certs_len);
> > > +	if (IS_ERR(plat_certs)) {
> > > +		ret = PTR_ERR(plat_certs);
> > > +		goto e_free_pdh;
> > > +	}
> > > +
> > > +	amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
> > > +				params.amd_certs_len);
> > > +	if (IS_ERR(amd_certs)) {
> > > +		ret = PTR_ERR(amd_certs);
> > > +		goto e_free_plat_cert;
> > > +	}
> > > +
> > > +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> > > +	if (data == NULL) {
> > > +		ret = -ENOMEM;
> > > +		goto e_free_amd_cert;
> > > +	}
> > > +
> > > +	/* populate the FW SEND_START field with system physical address */
> > > +	data->pdh_cert_address = __psp_pa(pdh_cert);
> > > +	data->pdh_cert_len = params.pdh_cert_len;
> > > +	data->plat_certs_address = __psp_pa(plat_certs);
> > > +	data->plat_certs_len = params.plat_certs_len;
> > > +	data->amd_certs_address = __psp_pa(amd_certs);
> > > +	data->amd_certs_len = params.amd_certs_len;
> > > +	data->session_address = __psp_pa(session_data);
> > > +	data->session_len = params.session_len;
> > > +	data->handle = sev->handle;
> > > +
> > 
> > Can the following code be changed as acknowledged in
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2Ff715bf99-0158-4d5f-77f3-b27743db3c59%40amd.com%2F&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7C5ea8d5ae78814a01618908d7f06f7667%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242233846323835&amp;sdata=5hbjsP%2Btxt2rdv2PtIc%2BV8cAwKUNsRdtiRglDupYXzs%3D&amp;reserved=0?
> > 
> 
> I believe that this has been already addressed as discussed :
> 
> Ah, so the main issue is we should not be going to e_free on error. If
> session_len is less than the expected len then FW will return an error.
> In the case of an error we can skip copying the session_data into
> userspace buffer but we still need to pass the session_len and policy
> back to the userspace.
> 
> So this patch is still returning session_len and policy back to user
> in case of error : ( as the code below shows )
> 
> if (!ret && copy_to_user((void
> __user*)(uintptr_t)params.session_uaddr,...

This fix addresses only one part of the problem. I am referring to the
other suggestion about avoiding copying the entire kvm_sev_send_start
structure back to the user. As I was mentioning in the discussion,
the only fields that changed are the policy and session_len fields. So,
why copy back the entire structure? Why not just those two fields?

> 
> Thanks,
> Ashish
> 
> > > +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> > > +
> > > +	if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
> > > +			session_data, params.session_len)) {
> > > +		ret = -EFAULT;
> > > +		goto e_free;
> > > +	}
> > > +
> > > +	params.policy = data->policy;
> > > +	params.session_len = data->session_len;
> > > +	if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
> > > +				sizeof(struct kvm_sev_send_start)))
> > > +		ret = -EFAULT;
> > > +
> > > +e_free:
> > > +	kfree(data);
> > > +e_free_amd_cert:
> > > +	kfree(amd_certs);
> > > +e_free_plat_cert:
> > > +	kfree(plat_certs);
> > > +e_free_pdh:
> > > +	kfree(pdh_cert);
> > > +e_free_session:
> > > +	kfree(session_data);
> > > +	return ret;
> > > +}
> > > +
> > >  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> > >  {
> > >  	struct kvm_sev_cmd sev_cmd;
> > > @@ -957,6 +1079,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> > >  	case KVM_SEV_LAUNCH_SECRET:
> > >  		r = sev_launch_secret(kvm, &sev_cmd);
> > >  		break;
> > > +	case KVM_SEV_SEND_START:
> > > +		r = sev_send_start(kvm, &sev_cmd);
> > > +		break;
> > >  	default:
> > >  		r = -EINVAL;
> > >  		goto out;
> > > diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> > > index 5167bf2bfc75..9f63b9d48b63 100644
> > > --- a/include/linux/psp-sev.h
> > > +++ b/include/linux/psp-sev.h
> > > @@ -323,11 +323,11 @@ struct sev_data_send_start {
> > >  	u64 pdh_cert_address;			/* In */
> > >  	u32 pdh_cert_len;			/* In */
> > >  	u32 reserved1;
> > > -	u64 plat_cert_address;			/* In */
> > > -	u32 plat_cert_len;			/* In */
> > > +	u64 plat_certs_address;			/* In */
> > > +	u32 plat_certs_len;			/* In */
> > >  	u32 reserved2;
> > > -	u64 amd_cert_address;			/* In */
> > > -	u32 amd_cert_len;			/* In */
> > > +	u64 amd_certs_address;			/* In */
> > > +	u32 amd_certs_len;			/* In */
> > >  	u32 reserved3;
> > >  	u64 session_address;			/* In */
> > >  	u32 session_len;			/* In/Out */
> > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > > index 428c7dde6b4b..8827d43e2684 100644
> > > --- a/include/uapi/linux/kvm.h
> > > +++ b/include/uapi/linux/kvm.h
> > > @@ -1598,6 +1598,18 @@ struct kvm_sev_dbg {
> > >  	__u32 len;
> > >  };
> > >  
> > > +struct kvm_sev_send_start {
> > > +	__u32 policy;
> > > +	__u64 pdh_cert_uaddr;
> > > +	__u32 pdh_cert_len;
> > > +	__u64 plat_certs_uaddr;
> > > +	__u32 plat_certs_len;
> > > +	__u64 amd_certs_uaddr;
> > > +	__u32 amd_certs_len;
> > > +	__u64 session_uaddr;
> > > +	__u32 session_len;
> > > +};
> > > +
> > >  #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
> > >  #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
> > >  #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)
> > > -- 
> > > 2.17.1
> > >
Kalra, Ashish May 4, 2020, 11:37 p.m. UTC | #4
On Mon, May 04, 2020 at 06:10:50PM -0500, Venu Busireddy wrote:
> On 2020-05-04 22:36:37 +0000, Ashish Kalra wrote:
> > On Mon, May 04, 2020 at 04:07:17PM -0500, Venu Busireddy wrote:
> > > On 2020-04-30 08:40:34 +0000, Ashish Kalra wrote:
> > > > From: Brijesh Singh <Brijesh.Singh@amd.com>
> > > > 
> > > > The command is used to create an outgoing SEV guest encryption context.
> > > > 
> > > > Cc: Thomas Gleixner <tglx@linutronix.de>
> > > > Cc: Ingo Molnar <mingo@redhat.com>
> > > > Cc: "H. Peter Anvin" <hpa@zytor.com>
> > > > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > > > Cc: "Radim Krčmář" <rkrcmar@redhat.com>
> > > > Cc: Joerg Roedel <joro@8bytes.org>
> > > > Cc: Borislav Petkov <bp@suse.de>
> > > > Cc: Tom Lendacky <thomas.lendacky@amd.com>
> > > > Cc: x86@kernel.org
> > > > Cc: kvm@vger.kernel.org
> > > > Cc: linux-kernel@vger.kernel.org
> > > > Reviewed-by: Steve Rutherford <srutherford@google.com>
> > > > Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
> > > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> > > > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> > > > ---
> > > >  .../virt/kvm/amd-memory-encryption.rst        |  27 ++++
> > > >  arch/x86/kvm/svm/sev.c                        | 125 ++++++++++++++++++
> > > >  include/linux/psp-sev.h                       |   8 +-
> > > >  include/uapi/linux/kvm.h                      |  12 ++
> > > >  4 files changed, 168 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
> > > > index c3129b9ba5cb..4fd34fc5c7a7 100644
> > > > --- a/Documentation/virt/kvm/amd-memory-encryption.rst
> > > > +++ b/Documentation/virt/kvm/amd-memory-encryption.rst
> > > > @@ -263,6 +263,33 @@ Returns: 0 on success, -negative on error
> > > >                  __u32 trans_len;
> > > >          };
> > > >  
> > > > +10. KVM_SEV_SEND_START
> > > > +----------------------
> > > > +
> > > > +The KVM_SEV_SEND_START command can be used by the hypervisor to create an
> > > > +outgoing guest encryption context.
> > > > +
> > > > +Parameters (in): struct kvm_sev_send_start
> > > > +
> > > > +Returns: 0 on success, -negative on error
> > > > +
> > > > +::
> > > > +        struct kvm_sev_send_start {
> > > > +                __u32 policy;                 /* guest policy */
> > > > +
> > > > +                __u64 pdh_cert_uaddr;         /* platform Diffie-Hellman certificate */
> > > > +                __u32 pdh_cert_len;
> > > > +
> > > > +                __u64 plat_certs_uadr;        /* platform certificate chain */
> > > 
> > > Can this be changed as mentioned in the previous review
> > > (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2F20200402062726.GA647295%40vbusired-dt%2F&amp;data=02%7C01%7Cashish.kalra%40amd.com%7Cf8d037dd37224ed4a33608d7f08067f5%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242306610788233&amp;sdata=eu1SgC6ukawOuxTeAoA3mzKiMNWlPCCa5lGEVs9D1s0%3D&amp;reserved=0)?
> > > 
> > > > +                __u32 plat_certs_len;
> > > > +
> > > > +                __u64 amd_certs_uaddr;        /* AMD certificate */
> > > > +                __u32 amd_cert_len;
> > > 
> > > Can this be changed as mentioned in the previous review
> > > (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2F20200402062726.GA647295%40vbusired-dt%2F&amp;data=02%7C01%7Cashish.kalra%40amd.com%7Cf8d037dd37224ed4a33608d7f08067f5%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242306610798235&amp;sdata=7xgp4ko8VGokGGQz1X1yPhz1ZXY9R501YginoDcen90%3D&amp;reserved=0)?
> > > 
> > > > +
> > > > +                __u64 session_uaddr;          /* Guest session information */
> > > > +                __u32 session_len;
> > > > +        };
> > > > +
> > > >  References
> > > >  ==========
> > > >  
> > > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > > > index cf912b4aaba8..5a15b43b4349 100644
> > > > --- a/arch/x86/kvm/svm/sev.c
> > > > +++ b/arch/x86/kvm/svm/sev.c
> > > > @@ -913,6 +913,128 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
> > > >  	return ret;
> > > >  }
> > > >  
> > > > +/* Userspace wants to query session length. */
> > > > +static int
> > > > +__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
> > > > +				      struct kvm_sev_send_start *params)
> > > > +{
> > > > +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > > > +	struct sev_data_send_start *data;
> > > > +	int ret;
> > > > +
> > > > +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> > > > +	if (data == NULL)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	data->handle = sev->handle;
> > > > +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> > > > +
> > > > +	params->session_len = data->session_len;
> > > > +	if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
> > > > +				sizeof(struct kvm_sev_send_start)))
> > > > +		ret = -EFAULT;
> > > > +
> > > > +	kfree(data);
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
> > > > +{
> > > > +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > > > +	struct sev_data_send_start *data;
> > > > +	struct kvm_sev_send_start params;
> > > > +	void *amd_certs, *session_data;
> > > > +	void *pdh_cert, *plat_certs;
> > > > +	int ret;
> > > > +
> > > > +	if (!sev_guest(kvm))
> > > > +		return -ENOTTY;
> > > > +
> > > > +	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
> > > > +				sizeof(struct kvm_sev_send_start)))
> > > > +		return -EFAULT;
> > > > +
> > > > +	/* if session_len is zero, userspace wants to query the session length */
> > > > +	if (!params.session_len)
> > > > +		return __sev_send_start_query_session_length(kvm, argp,
> > > > +				&params);
> > > > +
> > > > +	/* some sanity checks */
> > > > +	if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
> > > > +	    !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
> > > > +		return -EINVAL;
> > > > +
> > > > +	/* allocate the memory to hold the session data blob */
> > > > +	session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
> > > > +	if (!session_data)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	/* copy the certificate blobs from userspace */
> > > > +	pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr,
> > > > +				params.pdh_cert_len);
> > > > +	if (IS_ERR(pdh_cert)) {
> > > > +		ret = PTR_ERR(pdh_cert);
> > > > +		goto e_free_session;
> > > > +	}
> > > > +
> > > > +	plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
> > > > +				params.plat_certs_len);
> > > > +	if (IS_ERR(plat_certs)) {
> > > > +		ret = PTR_ERR(plat_certs);
> > > > +		goto e_free_pdh;
> > > > +	}
> > > > +
> > > > +	amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
> > > > +				params.amd_certs_len);
> > > > +	if (IS_ERR(amd_certs)) {
> > > > +		ret = PTR_ERR(amd_certs);
> > > > +		goto e_free_plat_cert;
> > > > +	}
> > > > +
> > > > +	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> > > > +	if (data == NULL) {
> > > > +		ret = -ENOMEM;
> > > > +		goto e_free_amd_cert;
> > > > +	}
> > > > +
> > > > +	/* populate the FW SEND_START field with system physical address */
> > > > +	data->pdh_cert_address = __psp_pa(pdh_cert);
> > > > +	data->pdh_cert_len = params.pdh_cert_len;
> > > > +	data->plat_certs_address = __psp_pa(plat_certs);
> > > > +	data->plat_certs_len = params.plat_certs_len;
> > > > +	data->amd_certs_address = __psp_pa(amd_certs);
> > > > +	data->amd_certs_len = params.amd_certs_len;
> > > > +	data->session_address = __psp_pa(session_data);
> > > > +	data->session_len = params.session_len;
> > > > +	data->handle = sev->handle;
> > > > +
> > > 
> > > Can the following code be changed as acknowledged in
> > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fkvm%2Ff715bf99-0158-4d5f-77f3-b27743db3c59%40amd.com%2F&amp;data=02%7C01%7Cashish.kalra%40amd.com%7Cf8d037dd37224ed4a33608d7f08067f5%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637242306610798235&amp;sdata=s3ZwfpCm94x2LCNN8I1jjcWcrkj3Nrw5PnOvxdDxSCs%3D&amp;reserved=0?
> > > 
> > 
> > I believe that this has been already addressed as discussed :
> > 
> > Ah, so the main issue is we should not be going to e_free on error. If
> > session_len is less than the expected len then FW will return an error.
> > In the case of an error we can skip copying the session_data into
> > userspace buffer but we still need to pass the session_len and policy
> > back to the userspace.
> > 
> > So this patch is still returning session_len and policy back to user
> > in case of error : ( as the code below shows )
> > 
> > if (!ret && copy_to_user((void
> > __user*)(uintptr_t)params.session_uaddr,...
> 
> This fix addresses only one part of the problem. I am referring to the
> other suggestion about avoiding copying the entire kvm_sev_send_start
> structure back to the user. As I was mentioning in the discussion,
> the only fields that changed are the policy and session_len fields. So,
> why copy back the entire structure? Why not just those two fields?
> 
> > 

Both policy and session_len are two different fields in the
kvm_sev_send_start structure, why to complicate it by using two
different copy_to_user()'s here, to send two 32-bit words back to user,
it's much simpler to copy the whole structure back in one copy_to_user() 
(makes it less complicated with no additional address computations),
also this is just a session start code, so it is invoked once at
the beginning of the migration process and it is not a performance
critical path such that saving few bytes of copy_to_user() wil affect it.

Thanks,
Ashish

> > 
> > > > +	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
> > > > +
> > > > +	if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
> > > > +			session_data, params.session_len)) {
> > > > +		ret = -EFAULT;
> > > > +		goto e_free;
> > > > +	}
> > > > +
> > > > +	params.policy = data->policy;
> > > > +	params.session_len = data->session_len;
> > > > +	if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
> > > > +				sizeof(struct kvm_sev_send_start)))
> > > > +		ret = -EFAULT;
> > > > +
> > > > +e_free:
> > > > +	kfree(data);
> > > > +e_free_amd_cert:
> > > > +	kfree(amd_certs);
> > > > +e_free_plat_cert:
> > > > +	kfree(plat_certs);
> > > > +e_free_pdh:
> > > > +	kfree(pdh_cert);
> > > > +e_free_session:
> > > > +	kfree(session_data);
> > > > +	return ret;
> > > > +}
> > > > +
> > > >  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> > > >  {
> > > >  	struct kvm_sev_cmd sev_cmd;
> > > > @@ -957,6 +1079,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> > > >  	case KVM_SEV_LAUNCH_SECRET:
> > > >  		r = sev_launch_secret(kvm, &sev_cmd);
> > > >  		break;
> > > > +	case KVM_SEV_SEND_START:
> > > > +		r = sev_send_start(kvm, &sev_cmd);
> > > > +		break;
> > > >  	default:
> > > >  		r = -EINVAL;
> > > >  		goto out;
> > > > diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> > > > index 5167bf2bfc75..9f63b9d48b63 100644
> > > > --- a/include/linux/psp-sev.h
> > > > +++ b/include/linux/psp-sev.h
> > > > @@ -323,11 +323,11 @@ struct sev_data_send_start {
> > > >  	u64 pdh_cert_address;			/* In */
> > > >  	u32 pdh_cert_len;			/* In */
> > > >  	u32 reserved1;
> > > > -	u64 plat_cert_address;			/* In */
> > > > -	u32 plat_cert_len;			/* In */
> > > > +	u64 plat_certs_address;			/* In */
> > > > +	u32 plat_certs_len;			/* In */
> > > >  	u32 reserved2;
> > > > -	u64 amd_cert_address;			/* In */
> > > > -	u32 amd_cert_len;			/* In */
> > > > +	u64 amd_certs_address;			/* In */
> > > > +	u32 amd_certs_len;			/* In */
> > > >  	u32 reserved3;
> > > >  	u64 session_address;			/* In */
> > > >  	u32 session_len;			/* In/Out */
> > > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > > > index 428c7dde6b4b..8827d43e2684 100644
> > > > --- a/include/uapi/linux/kvm.h
> > > > +++ b/include/uapi/linux/kvm.h
> > > > @@ -1598,6 +1598,18 @@ struct kvm_sev_dbg {
> > > >  	__u32 len;
> > > >  };
> > > >  
> > > > +struct kvm_sev_send_start {
> > > > +	__u32 policy;
> > > > +	__u64 pdh_cert_uaddr;
> > > > +	__u32 pdh_cert_len;
> > > > +	__u64 plat_certs_uaddr;
> > > > +	__u32 plat_certs_len;
> > > > +	__u64 amd_certs_uaddr;
> > > > +	__u32 amd_certs_len;
> > > > +	__u64 session_uaddr;
> > > > +	__u32 session_len;
> > > > +};
> > > > +
> > > >  #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
> > > >  #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
> > > >  #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)
> > > > -- 
> > > > 2.17.1
> > > >
diff mbox series

Patch

diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index c3129b9ba5cb..4fd34fc5c7a7 100644
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst
@@ -263,6 +263,33 @@  Returns: 0 on success, -negative on error
                 __u32 trans_len;
         };
 
+10. KVM_SEV_SEND_START
+----------------------
+
+The KVM_SEV_SEND_START command can be used by the hypervisor to create an
+outgoing guest encryption context.
+
+Parameters (in): struct kvm_sev_send_start
+
+Returns: 0 on success, -negative on error
+
+::
+        struct kvm_sev_send_start {
+                __u32 policy;                 /* guest policy */
+
+                __u64 pdh_cert_uaddr;         /* platform Diffie-Hellman certificate */
+                __u32 pdh_cert_len;
+
+                __u64 plat_certs_uadr;        /* platform certificate chain */
+                __u32 plat_certs_len;
+
+                __u64 amd_certs_uaddr;        /* AMD certificate */
+                __u32 amd_cert_len;
+
+                __u64 session_uaddr;          /* Guest session information */
+                __u32 session_len;
+        };
+
 References
 ==========
 
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index cf912b4aaba8..5a15b43b4349 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -913,6 +913,128 @@  static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return ret;
 }
 
+/* Userspace wants to query session length. */
+static int
+__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
+				      struct kvm_sev_send_start *params)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_send_start *data;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+	if (data == NULL)
+		return -ENOMEM;
+
+	data->handle = sev->handle;
+	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+
+	params->session_len = data->session_len;
+	if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
+				sizeof(struct kvm_sev_send_start)))
+		ret = -EFAULT;
+
+	kfree(data);
+	return ret;
+}
+
+static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_send_start *data;
+	struct kvm_sev_send_start params;
+	void *amd_certs, *session_data;
+	void *pdh_cert, *plat_certs;
+	int ret;
+
+	if (!sev_guest(kvm))
+		return -ENOTTY;
+
+	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
+				sizeof(struct kvm_sev_send_start)))
+		return -EFAULT;
+
+	/* if session_len is zero, userspace wants to query the session length */
+	if (!params.session_len)
+		return __sev_send_start_query_session_length(kvm, argp,
+				&params);
+
+	/* some sanity checks */
+	if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
+	    !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
+		return -EINVAL;
+
+	/* allocate the memory to hold the session data blob */
+	session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
+	if (!session_data)
+		return -ENOMEM;
+
+	/* copy the certificate blobs from userspace */
+	pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr,
+				params.pdh_cert_len);
+	if (IS_ERR(pdh_cert)) {
+		ret = PTR_ERR(pdh_cert);
+		goto e_free_session;
+	}
+
+	plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
+				params.plat_certs_len);
+	if (IS_ERR(plat_certs)) {
+		ret = PTR_ERR(plat_certs);
+		goto e_free_pdh;
+	}
+
+	amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
+				params.amd_certs_len);
+	if (IS_ERR(amd_certs)) {
+		ret = PTR_ERR(amd_certs);
+		goto e_free_plat_cert;
+	}
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+	if (data == NULL) {
+		ret = -ENOMEM;
+		goto e_free_amd_cert;
+	}
+
+	/* populate the FW SEND_START field with system physical address */
+	data->pdh_cert_address = __psp_pa(pdh_cert);
+	data->pdh_cert_len = params.pdh_cert_len;
+	data->plat_certs_address = __psp_pa(plat_certs);
+	data->plat_certs_len = params.plat_certs_len;
+	data->amd_certs_address = __psp_pa(amd_certs);
+	data->amd_certs_len = params.amd_certs_len;
+	data->session_address = __psp_pa(session_data);
+	data->session_len = params.session_len;
+	data->handle = sev->handle;
+
+	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+
+	if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
+			session_data, params.session_len)) {
+		ret = -EFAULT;
+		goto e_free;
+	}
+
+	params.policy = data->policy;
+	params.session_len = data->session_len;
+	if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
+				sizeof(struct kvm_sev_send_start)))
+		ret = -EFAULT;
+
+e_free:
+	kfree(data);
+e_free_amd_cert:
+	kfree(amd_certs);
+e_free_plat_cert:
+	kfree(plat_certs);
+e_free_pdh:
+	kfree(pdh_cert);
+e_free_session:
+	kfree(session_data);
+	return ret;
+}
+
 int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
@@ -957,6 +1079,9 @@  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_LAUNCH_SECRET:
 		r = sev_launch_secret(kvm, &sev_cmd);
 		break;
+	case KVM_SEV_SEND_START:
+		r = sev_send_start(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index 5167bf2bfc75..9f63b9d48b63 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -323,11 +323,11 @@  struct sev_data_send_start {
 	u64 pdh_cert_address;			/* In */
 	u32 pdh_cert_len;			/* In */
 	u32 reserved1;
-	u64 plat_cert_address;			/* In */
-	u32 plat_cert_len;			/* In */
+	u64 plat_certs_address;			/* In */
+	u32 plat_certs_len;			/* In */
 	u32 reserved2;
-	u64 amd_cert_address;			/* In */
-	u32 amd_cert_len;			/* In */
+	u64 amd_certs_address;			/* In */
+	u32 amd_certs_len;			/* In */
 	u32 reserved3;
 	u64 session_address;			/* In */
 	u32 session_len;			/* In/Out */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 428c7dde6b4b..8827d43e2684 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1598,6 +1598,18 @@  struct kvm_sev_dbg {
 	__u32 len;
 };
 
+struct kvm_sev_send_start {
+	__u32 policy;
+	__u64 pdh_cert_uaddr;
+	__u32 pdh_cert_len;
+	__u64 plat_certs_uaddr;
+	__u32 plat_certs_len;
+	__u64 amd_certs_uaddr;
+	__u32 amd_certs_len;
+	__u64 session_uaddr;
+	__u32 session_len;
+};
+
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
 #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)