Re: [Part2 PATCH v6.1 16/38] crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support

[Brijesh Singh]

I just realized that this should be marked as "PATCH v6.1 13/38 ...". I
had some debug patch before this hence it was pushed below in the stack.


On 10/29/17 3:48 PM, Brijesh Singh wrote:
> AMD's new Secure Encrypted Virtualization (SEV) feature allows the
> memory contents of virtual machines to be transparently encrypted with a
> key unique to the VM. The programming and management of the encryption
> keys are handled by the AMD Secure Processor (AMD-SP) which exposes the
> commands for these tasks. The complete spec is available at:
>
> http://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf
>
> Extend the AMD-SP driver to provide the following support:
>
>  - an in-kernel API to communicate with the SEV firmware. The API can be
>    used by the hypervisor to create encryption context for a SEV guest.
>
>  - a userspace IOCTL to manage the platform certificates.
>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: "Radim KrÄmÃÅ" <rkrcmar@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: Gary Hook <gary.hook@xxxxxxx>
> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
> Cc: linux-crypto@xxxxxxxxxxxxxxx
> Cc: kvm@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Improvements-by: Borislav Petkov <bp@xxxxxxx>
> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
> ---
>
> Boris,
>
> I have tried to minimize the INIT -> SHUTDOWN transition by keeping state
> information in sev_state variable. Since we INIT the platform during the
> modprobe time hence we no longer need the kref count and init mutex.
> Here are list of changes.
>
> Changes since v6:
>  * Add functions to init and shutdown firmware during modprobe
>  * Add sev_state variable in psp_device to keep track of the INIT and SHUTDOWN
>    state
>  * Don't allow caller to shutdown the FW because SHUTDOWN will be done during
>    the module removal.
>  * Drop the fw_init_mutex and init_refcount because we no longer allow apps to
>    INIT and UINIT the platform
>
>  drivers/crypto/ccp/psp-dev.c | 360 +++++++++++++++++++++++++++++++++++++++++++
>  drivers/crypto/ccp/psp-dev.h |  22 +++
>  drivers/crypto/ccp/sp-dev.c  |   9 ++
>  drivers/crypto/ccp/sp-dev.h  |   4 +
>  include/linux/psp-sev.h      | 158 +++++++++++++++++++
>  5 files changed, 553 insertions(+)
>
> diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
> index b5789f878560..060f57ac08b3 100644
> --- a/drivers/crypto/ccp/psp-dev.c
> +++ b/drivers/crypto/ccp/psp-dev.c
> @@ -26,6 +26,15 @@
>  #include "sp-dev.h"
>  #include "psp-dev.h"
>  
> +#define DEVICE_NAME	"sev"
> +
> +static DEFINE_MUTEX(sev_cmd_mutex);
> +static struct sev_misc_dev *misc_dev;
> +static struct psp_device *psp_master;
> +
> +static int sev_platform_shutdown_locked(int *error);
> +static int sev_platform_init_locked(struct sev_data_init *data, int *error);
> +
>  static struct psp_device *psp_alloc_struct(struct sp_device *sp)
>  {
>  	struct device *dev = sp->dev;
> @@ -45,9 +54,304 @@ static struct psp_device *psp_alloc_struct(struct sp_device *sp)
>  
>  static irqreturn_t psp_irq_handler(int irq, void *data)
>  {
> +	struct psp_device *psp = data;
> +	unsigned int status;
> +	int reg;
> +
> +	/* Read the interrupt status: */
> +	status = ioread32(psp->io_regs + PSP_P2CMSG_INTSTS);
> +
> +	/* Check if it is command completion: */
> +	if (!(status & BIT(PSP_CMD_COMPLETE_REG)))
> +		goto done;
> +
> +	/* Check if it is SEV command completion: */
> +	reg = ioread32(psp->io_regs + PSP_CMDRESP);
> +	if (reg & PSP_CMDRESP_RESP) {
> +		psp->sev_int_rcvd = 1;
> +		wake_up(&psp->sev_int_queue);
> +	}
> +
> +done:
> +	/* Clear the interrupt status by writing the same value we read. */
> +	iowrite32(status, psp->io_regs + PSP_P2CMSG_INTSTS);
> +
>  	return IRQ_HANDLED;
>  }
>  
> +static void sev_wait_cmd_ioc(struct psp_device *psp, unsigned int *reg)
> +{
> +	psp->sev_int_rcvd = 0;
> +
> +	wait_event(psp->sev_int_queue, psp->sev_int_rcvd);
> +	*reg = ioread32(psp->io_regs + PSP_CMDRESP);
> +}
> +
> +static int sev_cmd_buffer_len(int cmd)
> +{
> +	switch (cmd) {
> +	case SEV_CMD_INIT:			return sizeof(struct sev_data_init);
> +	case SEV_CMD_PLATFORM_STATUS:		return sizeof(struct sev_user_data_status);
> +	case SEV_CMD_PEK_CSR:			return sizeof(struct sev_data_pek_csr);
> +	case SEV_CMD_PEK_CERT_IMPORT:		return sizeof(struct sev_data_pek_cert_import);
> +	case SEV_CMD_PDH_CERT_EXPORT:		return sizeof(struct sev_data_pdh_cert_export);
> +	case SEV_CMD_LAUNCH_START:		return sizeof(struct sev_data_launch_start);
> +	case SEV_CMD_LAUNCH_UPDATE_DATA:	return sizeof(struct sev_data_launch_update_data);
> +	case SEV_CMD_LAUNCH_UPDATE_VMSA:	return sizeof(struct sev_data_launch_update_vmsa);
> +	case SEV_CMD_LAUNCH_FINISH:		return sizeof(struct sev_data_launch_finish);
> +	case SEV_CMD_LAUNCH_MEASURE:		return sizeof(struct sev_data_launch_measure);
> +	case SEV_CMD_ACTIVATE:			return sizeof(struct sev_data_activate);
> +	case SEV_CMD_DEACTIVATE:		return sizeof(struct sev_data_deactivate);
> +	case SEV_CMD_DECOMMISSION:		return sizeof(struct sev_data_decommission);
> +	case SEV_CMD_GUEST_STATUS:		return sizeof(struct sev_data_guest_status);
> +	case SEV_CMD_DBG_DECRYPT:		return sizeof(struct sev_data_dbg);
> +	case SEV_CMD_DBG_ENCRYPT:		return sizeof(struct sev_data_dbg);
> +	case SEV_CMD_SEND_START:		return sizeof(struct sev_data_send_start);
> +	case SEV_CMD_SEND_UPDATE_DATA:		return sizeof(struct sev_data_send_update_data);
> +	case SEV_CMD_SEND_UPDATE_VMSA:		return sizeof(struct sev_data_send_update_vmsa);
> +	case SEV_CMD_SEND_FINISH:		return sizeof(struct sev_data_send_finish);
> +	case SEV_CMD_RECEIVE_START:		return sizeof(struct sev_data_receive_start);
> +	case SEV_CMD_RECEIVE_FINISH:		return sizeof(struct sev_data_receive_finish);
> +	case SEV_CMD_RECEIVE_UPDATE_DATA:	return sizeof(struct sev_data_receive_update_data);
> +	case SEV_CMD_RECEIVE_UPDATE_VMSA:	return sizeof(struct sev_data_receive_update_vmsa);
> +	case SEV_CMD_LAUNCH_UPDATE_SECRET:	return sizeof(struct sev_data_launch_secret);
> +	default:				return 0;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
> +{
> +	struct psp_device *psp = psp_master;
> +	unsigned int phys_lsb, phys_msb;
> +	unsigned int reg, ret = 0;
> +
> +	if (!psp)
> +		return -ENODEV;
> +
> +	/* Get the physical address of the command buffer */
> +	phys_lsb = data ? lower_32_bits(__psp_pa(data)) : 0;
> +	phys_msb = data ? upper_32_bits(__psp_pa(data)) : 0;
> +
> +	dev_dbg(psp->dev, "sev command id %#x buffer 0x%08x%08x\n",
> +		cmd, phys_msb, phys_lsb);
> +
> +	print_hex_dump_debug("(in):  ", DUMP_PREFIX_OFFSET, 16, 2, data,
> +			     sev_cmd_buffer_len(cmd), false);
> +
> +	iowrite32(phys_lsb, psp->io_regs + PSP_CMDBUFF_ADDR_LO);
> +	iowrite32(phys_msb, psp->io_regs + PSP_CMDBUFF_ADDR_HI);
> +
> +	reg = cmd;
> +	reg <<= PSP_CMDRESP_CMD_SHIFT;
> +	reg |= PSP_CMDRESP_IOC;
> +	iowrite32(reg, psp->io_regs + PSP_CMDRESP);
> +
> +	/* wait for command completion */
> +	sev_wait_cmd_ioc(psp, &reg);
> +
> +	if (psp_ret)
> +		*psp_ret = reg & PSP_CMDRESP_ERR_MASK;
> +
> +	if (reg & PSP_CMDRESP_ERR_MASK) {
> +		dev_dbg(psp->dev, "sev command %#x failed (%#010x)\n",
> +			cmd, reg & PSP_CMDRESP_ERR_MASK);
> +		ret = -EIO;
> +	}
> +
> +	print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data,
> +			     sev_cmd_buffer_len(cmd), false);
> +
> +	return ret;
> +}
> +
> +static int sev_do_cmd(int cmd, void *data, int *psp_ret)
> +{
> +	int rc;
> +
> +	mutex_lock(&sev_cmd_mutex);
> +	rc = sev_do_cmd_locked(cmd, data, psp_ret);
> +	mutex_unlock(&sev_cmd_mutex);
> +
> +	return rc;
> +}
> +
> +static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
> +{
> +	return -ENOTTY;
> +}
> +
> +static const struct file_operations sev_fops = {
> +	.owner	= THIS_MODULE,
> +	.unlocked_ioctl = sev_ioctl,
> +};
> +
> +static int sev_platform_init_locked(struct sev_data_init *data, int *error)
> +{
> +	struct psp_device *psp = psp_master;
> +	struct sev_data_init *input = NULL;
> +	int rc = 0;
> +
> +	if (!psp)
> +		return -ENODEV;
> +
> +	if (psp->sev_state == SEV_STATE_INIT)
> +		return 0;
> +
> +	if (!data) {
> +		input = kzalloc(sizeof(*input), GFP_KERNEL);
> +		if (!input)
> +			return -ENOMEM;
> +
> +		data = input;
> +	}
> +
> +	rc = sev_do_cmd_locked(SEV_CMD_INIT, data, error);
> +	if (rc)
> +		goto e_free;
> +
> +	psp->sev_state = SEV_STATE_INIT;
> +	dev_dbg(psp->dev, "SEV firmware intialized\n");
> +
> +e_free:
> +	kfree(input);
> +	return rc;
> +}
> +
> +int sev_platform_init(struct sev_data_init *data, int *error)
> +{
> +	int rc;
> +
> +	mutex_lock(&sev_cmd_mutex);
> +	rc = sev_platform_init_locked(data, error);
> +	mutex_unlock(&sev_cmd_mutex);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(sev_platform_init);
> +
> +static int sev_platform_shutdown_locked(int *error)
> +{
> +	int ret;
> +
> +	ret = sev_do_cmd_locked(SEV_CMD_SHUTDOWN, 0, error);
> +	if (ret)
> +		return ret;
> +
> +	psp_master->sev_state = SEV_STATE_UNINIT;
> +	dev_dbg(psp_master->dev, "SEV firmware shutdown\n");
> +
> +	return ret;
> +}
> +
> +int sev_platform_shutdown(int *error)
> +{
> +	if (error)
> +		*error = 0;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(sev_platform_shutdown);
> +
> +int sev_platform_status(struct sev_user_data_status *data, int *error)
> +{
> +	return sev_do_cmd(SEV_CMD_PLATFORM_STATUS, data, error);
> +}
> +EXPORT_SYMBOL_GPL(sev_platform_status);
> +
> +int sev_issue_cmd_external_user(struct file *filep, unsigned int cmd,
> +				void *data, int *error)
> +{
> +	if (!filep || filep->f_op != &sev_fops)
> +		return -EBADF;
> +
> +	return  sev_do_cmd(cmd, data, error);
> +}
> +EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
> +
> +int sev_guest_deactivate(struct sev_data_deactivate *data, int *error)
> +{
> +	return sev_do_cmd(SEV_CMD_DEACTIVATE, data, error);
> +}
> +EXPORT_SYMBOL_GPL(sev_guest_deactivate);
> +
> +int sev_guest_activate(struct sev_data_activate *data, int *error)
> +{
> +	return sev_do_cmd(SEV_CMD_ACTIVATE, data, error);
> +}
> +EXPORT_SYMBOL_GPL(sev_guest_activate);
> +
> +int sev_guest_decommission(struct sev_data_decommission *data, int *error)
> +{
> +	return sev_do_cmd(SEV_CMD_DECOMMISSION, data, error);
> +}
> +EXPORT_SYMBOL_GPL(sev_guest_decommission);
> +
> +int sev_guest_df_flush(int *error)
> +{
> +	return sev_do_cmd(SEV_CMD_DF_FLUSH, 0, error);
> +}
> +EXPORT_SYMBOL_GPL(sev_guest_df_flush);
> +
> +static int sev_ops_init(struct psp_device *psp)
> +{
> +	struct device *dev = psp->dev;
> +	int ret;
> +
> +	/*
> +	 * SEV feature support can be detected on multiple devices but the SEV
> +	 * FW commands must be issued on the master. During probe, we do not
> +	 * know the master hence we create /dev/sev on the first device probe.
> +	 * sev_do_cmd() finds the right master device to which to issue the
> +	 * command to the firmware.
> +	 */
> +	if (!misc_dev) {
> +		struct miscdevice *misc;
> +
> +		misc_dev = devm_kzalloc(dev, sizeof(*misc_dev), GFP_KERNEL);
> +		if (!misc_dev)
> +			return -ENOMEM;
> +
> +		misc = &misc_dev->misc;
> +		misc->minor = MISC_DYNAMIC_MINOR;
> +		misc->name = DEVICE_NAME;
> +		misc->fops = &sev_fops;
> +
> +		ret = misc_register(misc);
> +		if (ret)
> +			return ret;
> +
> +		kref_init(&misc_dev->refcount);
> +	} else {
> +		kref_get(&misc_dev->refcount);
> +	}
> +
> +	init_waitqueue_head(&psp->sev_int_queue);
> +	psp->sev_misc = misc_dev;
> +	dev_dbg(dev, "registered SEV device\n");
> +
> +	return 0;
> +}
> +
> +static int sev_init(struct psp_device *psp)
> +{
> +	/* Check if device supports SEV feature */
> +	if (!(ioread32(psp->io_regs + PSP_FEATURE_REG) & 1)) {
> +		dev_dbg(psp->dev, "device does not support SEV\n");
> +		return 1;
> +	}
> +
> +	return sev_ops_init(psp);
> +}
> +
> +static void sev_exit(struct kref *ref)
> +{
> +	struct sev_misc_dev *misc_dev = container_of(ref, struct sev_misc_dev, refcount);
> +
> +	misc_deregister(&misc_dev->misc);
> +}
> +
>  int psp_dev_init(struct sp_device *sp)
>  {
>  	struct device *dev = sp->dev;
> @@ -84,11 +388,17 @@ int psp_dev_init(struct sp_device *sp)
>  	if (sp->set_psp_master_device)
>  		sp->set_psp_master_device(sp);
>  
> +	ret = sev_init(psp);
> +	if (ret)
> +		goto e_irq;
> +
>  	/* Enable interrupt */
>  	iowrite32(-1, psp->io_regs + PSP_P2CMSG_INTEN);
>  
>  	return 0;
>  
> +e_irq:
> +	sp_free_psp_irq(psp->sp, psp);
>  e_err:
>  	sp->psp_data = NULL;
>  
> @@ -101,5 +411,55 @@ void psp_dev_destroy(struct sp_device *sp)
>  {
>  	struct psp_device *psp = sp->psp_data;
>  
> +	if (psp->sev_misc)
> +		kref_put(&misc_dev->refcount, sev_exit);
> +
>  	sp_free_psp_irq(sp, psp);
>  }
> +
> +void psp_pci_init(void)
> +{
> +	struct sev_user_data_status *data;
> +	struct sp_device *sp;
> +	int error, rc;
> +
> +	sp = sp_get_psp_master_device();
> +	if (!sp)
> +		return;
> +
> +	psp_master = sp->psp_data;
> +
> +	/* Initialize the platform */
> +	rc = sev_platform_init(NULL, &error);
> +	if (rc) {
> +		dev_err(sp->dev, "SEV: failed to INIT error %#x\n", error);
> +		return;
> +	}
> +
> +	/* Display SEV firmware version */
> +	data = kzalloc(sizeof (*data), GFP_KERNEL);
> +	if (!data)
> +		return;
> +
> +	rc = sev_platform_status(data, &error);
> +	if (rc) {
> +		dev_err(sp->dev, "SEV: failed to get status error %#x\n", error);
> +		goto e_free;
> +	}
> +
> +	dev_info(sp->dev, "SEV API:%d.%d build:%d\n",
> +		 data->api_major, data->api_minor, data->build);
> +
> +e_free:
> +	kfree(data);
> +}
> +
> +void psp_pci_exit(void)
> +{
> +	if (!psp_master)
> +		return;
> +
> +	mutex_lock(&sev_cmd_mutex);
> +	sev_platform_shutdown_locked(NULL);
> +	mutex_unlock(&sev_cmd_mutex);
> +}
> diff --git a/drivers/crypto/ccp/psp-dev.h b/drivers/crypto/ccp/psp-dev.h
> index 55b7808367c3..98889b721904 100644
> --- a/drivers/crypto/ccp/psp-dev.h
> +++ b/drivers/crypto/ccp/psp-dev.h
> @@ -25,9 +25,21 @@
>  #include <linux/interrupt.h>
>  #include <linux/irqreturn.h>
>  #include <linux/dmaengine.h>
> +#include <linux/psp-sev.h>
> +#include <linux/miscdevice.h>
>  
>  #include "sp-dev.h"
>  
> +#define PSP_C2PMSG(_num)		((_num) << 2)
> +#define PSP_CMDRESP			PSP_C2PMSG(32)
> +#define PSP_CMDBUFF_ADDR_LO		PSP_C2PMSG(56)
> +#define PSP_CMDBUFF_ADDR_HI             PSP_C2PMSG(57)
> +#define PSP_FEATURE_REG			PSP_C2PMSG(63)
> +
> +#define PSP_P2CMSG(_num)		((_num) << 2)
> +#define PSP_CMD_COMPLETE_REG		1
> +#define PSP_CMD_COMPLETE		PSP_P2CMSG(PSP_CMD_COMPLETE_REG)
> +
>  #define PSP_P2CMSG_INTEN		0x0110
>  #define PSP_P2CMSG_INTSTS		0x0114
>  
> @@ -44,6 +56,11 @@
>  
>  #define MAX_PSP_NAME_LEN		16
>  
> +struct sev_misc_dev {
> +	struct kref refcount;
> +	struct miscdevice misc;
> +};
> +
>  struct psp_device {
>  	struct list_head entry;
>  
> @@ -54,6 +71,11 @@ struct psp_device {
>  	struct sp_device *sp;
>  
>  	void __iomem *io_regs;
> +
> +	int sev_state;
> +	unsigned int sev_int_rcvd;
> +	wait_queue_head_t sev_int_queue;
> +	struct sev_misc_dev *sev_misc;
>  };
>  
>  #endif /* __PSP_DEV_H */
> diff --git a/drivers/crypto/ccp/sp-dev.c b/drivers/crypto/ccp/sp-dev.c
> index cf101c039c8f..eb0da6572720 100644
> --- a/drivers/crypto/ccp/sp-dev.c
> +++ b/drivers/crypto/ccp/sp-dev.c
> @@ -272,6 +272,10 @@ static int __init sp_mod_init(void)
>  	if (ret)
>  		return ret;
>  
> +#ifdef CONFIG_CRYPTO_DEV_SP_PSP
> +	psp_pci_init();
> +#endif
> +
>  	return 0;
>  #endif
>  
> @@ -291,6 +295,11 @@ static int __init sp_mod_init(void)
>  static void __exit sp_mod_exit(void)
>  {
>  #ifdef CONFIG_X86
> +
> +#ifdef CONFIG_CRYPTO_DEV_SP_PSP
> +	psp_pci_exit();
> +#endif
> +
>  	sp_pci_exit();
>  #endif
>  
> diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
> index 909cf3e436b4..acb197b66ced 100644
> --- a/drivers/crypto/ccp/sp-dev.h
> +++ b/drivers/crypto/ccp/sp-dev.h
> @@ -143,12 +143,16 @@ static inline int ccp_dev_resume(struct sp_device *sp)
>  #ifdef CONFIG_CRYPTO_DEV_SP_PSP
>  
>  int psp_dev_init(struct sp_device *sp);
> +void psp_pci_init(void);
>  void psp_dev_destroy(struct sp_device *sp);
> +void psp_pci_exit(void);
>  
>  #else /* !CONFIG_CRYPTO_DEV_SP_PSP */
>  
>  static inline int psp_dev_init(struct sp_device *sp) { return 0; }
> +static inline void psp_pci_init(void) { }
>  static inline void psp_dev_destroy(struct sp_device *sp) { }
> +static inline void psp_pci_exit(void) { }
>  
>  #endif /* CONFIG_CRYPTO_DEV_SP_PSP */
>  
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index 15bda519538e..7ddce7dec464 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -491,4 +491,162 @@ struct sev_data_dbg {
>  	u32 len;				/* In */
>  } __packed;
>  
> +#ifdef CONFIG_CRYPTO_DEV_SP_PSP
> +
> +/**
> + * sev_platform_init - perform SEV INIT command
> + *
> + * @init: sev_data_init structure to be processed
> + * @error: SEV command return code
> + *
> + * Returns:
> + * 0 if the SEV successfully processed the command
> + * -%ENODEV    if the SEV device is not available
> + * -%ENOTSUPP  if the SEV does not support SEV
> + * -%ETIMEDOUT if the SEV command timed out
> + * -%EIO       if the SEV returned a non-zero return code
> + */
> +int sev_platform_init(struct sev_data_init *init, int *error);
> +
> +/**
> + * sev_platform_shutdown - perform SEV SHUTDOWN command
> + * @error: SEV command return code
> + *
> + * Returns:
> + * 0 if the SEV successfully processed the command
> + * -%ENODEV    if the SEV device is not available
> + * -%ENOTSUPP  if the SEV does not support SEV
> + * -%ETIMEDOUT if the SEV command timed out
> + * -%EIO       if the SEV returned a non-zero return code
> + */
> +int sev_platform_shutdown(int *error);
> +
> +/**
> + * sev_platform_status - perform SEV PLATFORM_STATUS command
> + *
> + * @status: sev_user_data_status structure to be processed
> + * @error: SEV command return code
> + *
> + * Returns:
> + * 0 if the SEV successfully processed the command
> + * -%ENODEV    if the SEV device is not available
> + * -%ENOTSUPP  if the SEV does not support SEV
> + * -%ETIMEDOUT if the SEV command timed out
> + * -%EIO       if the SEV returned a non-zero return code
> + */
> +int sev_platform_status(struct sev_user_data_status *status, int *error);
> +
> +/**
> + * sev_issue_cmd_external_user - issue SEV command by other driver with a file
> + * handle.
> + *
> + * This function can be used by other drivers to issue a SEV command on
> + * behalf of userspace. The caller must pass a valid SEV file descriptor
> + * so that we know that it has access to SEV device.
> + *
> + * @filep - SEV device file pointer
> + * @cmd - command to issue
> + * @data - command buffer
> + * @error: SEV command return code
> + *
> + * Returns:
> + * 0 if the SEV successfully processed the command
> + * -%ENODEV    if the SEV device is not available
> + * -%ENOTSUPP  if the SEV does not support SEV
> + * -%ETIMEDOUT if the SEV command timed out
> + * -%EIO       if the SEV returned a non-zero return code
> + * -%EINVAL    if the SEV file descriptor is not valid
> + */
> +int sev_issue_cmd_external_user(struct file *filep, unsigned int id,
> +				void *data, int *error);
> +
> +/**
> + * sev_guest_deactivate - perform SEV DEACTIVATE command
> + *
> + * @deactivate: sev_data_deactivate structure to be processed
> + * @sev_ret: sev command return code
> + *
> + * Returns:
> + * 0 if the sev successfully processed the command
> + * -%ENODEV    if the sev device is not available
> + * -%ENOTSUPP  if the sev does not support SEV
> + * -%ETIMEDOUT if the sev command timed out
> + * -%EIO       if the sev returned a non-zero return code
> + */
> +int sev_guest_deactivate(struct sev_data_deactivate *data, int *error);
> +
> +/**
> + * sev_guest_activate - perform SEV ACTIVATE command
> + *
> + * @activate: sev_data_activate structure to be processed
> + * @sev_ret: sev command return code
> + *
> + * Returns:
> + * 0 if the sev successfully processed the command
> + * -%ENODEV    if the sev device is not available
> + * -%ENOTSUPP  if the sev does not support SEV
> + * -%ETIMEDOUT if the sev command timed out
> + * -%EIO       if the sev returned a non-zero return code
> + */
> +int sev_guest_activate(struct sev_data_activate *data, int *error);
> +
> +/**
> + * sev_guest_df_flush - perform SEV DF_FLUSH command
> + *
> + * @sev_ret: sev command return code
> + *
> + * Returns:
> + * 0 if the sev successfully processed the command
> + * -%ENODEV    if the sev device is not available
> + * -%ENOTSUPP  if the sev does not support SEV
> + * -%ETIMEDOUT if the sev command timed out
> + * -%EIO       if the sev returned a non-zero return code
> + */
> +int sev_guest_df_flush(int *error);
> +
> +/**
> + * sev_guest_decommission - perform SEV DECOMMISSION command
> + *
> + * @decommission: sev_data_decommission structure to be processed
> + * @sev_ret: sev command return code
> + *
> + * Returns:
> + * 0 if the sev successfully processed the command
> + * -%ENODEV    if the sev device is not available
> + * -%ENOTSUPP  if the sev does not support SEV
> + * -%ETIMEDOUT if the sev command timed out
> + * -%EIO       if the sev returned a non-zero return code
> + */
> +int sev_guest_decommission(struct sev_data_decommission *data, int *error);
> +
> +#else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
> +
> +static inline int
> +sev_platform_status(struct sev_user_data_status *status, int *error) { return -ENODEV; }
> +
> +static inline int
> +sev_platform_init(struct sev_data_init *init, int *error) { return -ENODEV; }
> +
> +static inline int sev_platform_shutdown(int *error) { return -ENODEV; }
> +
> +static inline int
> +sev_guest_deactivate(struct sev_data_deactivate *data, int *error) { return -ENODEV; }
> +
> +static inline int
> +sev_guest_decommission(struct sev_data_decommission *data, int *error) { return -ENODEV; }
> +
> +static inline int
> +sev_guest_activate(struct sev_data_activate *data, int *error) { return -ENODEV; }
> +
> +static inline int sev_guest_df_flush(int *error) { return -ENODEV; }
> +
> +static inline int
> +sev_issue_cmd_external_user(struct file *filep,
> +			    unsigned int id, void *data, int *error)
> +{
> +	return -ENODEV;
> +}
> +
> +#endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
> +
>  #endif	/* __PSP_SEV_H__ */