crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support

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@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Gary Hook <gary.hook@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-crypto@vger.kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Improvements-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>

1 files changed, 344 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index b5789f878560..9915a6c604a3 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -26,6 +26,12 @@
 #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 struct psp_device *psp_alloc_struct(struct sp_device *sp)
 {
 	struct device *dev = sp->dev;
@@ -45,9 +51,285 @@ 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 int __sev_platform_init_locked(int *error)
+{
+	struct psp_device *psp = psp_master;
+	int rc = 0;
+
+	if (!psp)
+		return -ENODEV;
+
+	if (psp->sev_state == SEV_STATE_INIT)
+		return 0;
+
+	rc = __sev_do_cmd_locked(SEV_CMD_INIT, &psp->init_cmd_buf, error);
+	if (rc)
+		return rc;
+
+	psp->sev_state = SEV_STATE_INIT;
+	dev_dbg(psp->dev, "SEV firmware initialized\n");
+
+	return rc;
+}
+
+int sev_platform_init(int *error)
+{
+	int rc;
+
+	mutex_lock(&sev_cmd_mutex);
+	rc = __sev_platform_init_locked(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;
+}
+
+static int sev_platform_shutdown(int *error)
+{
+	int rc;
+
+	mutex_lock(&sev_cmd_mutex);
+	rc = __sev_platform_shutdown_locked(NULL);
+	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,
+};
+
+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_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 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);
+}
+
+static int sev_misc_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_misc_init(psp);
+}
+
 int psp_dev_init(struct sp_device *sp)
 {
 	struct device *dev = sp->dev;
@@ -81,6 +363,10 @@ int psp_dev_init(struct sp_device *sp)
 		goto e_err;
 	}
 
+	ret = sev_init(psp);
+	if (ret)
+		goto e_irq;
+
 	if (sp->set_psp_master_device)
 		sp->set_psp_master_device(sp);
 
@@ -89,6 +375,8 @@ int psp_dev_init(struct sp_device *sp)
 
 	return 0;
 
+e_irq:
+	sp_free_psp_irq(psp->sp, psp);
 e_err:
 	sp->psp_data = NULL;
 
@@ -101,5 +389,61 @@ 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);
 }
+
+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);
+
+void psp_pci_init(void)
+{
+	struct sev_user_data_status *status;
+	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(&error);
+	if (rc) {
+		dev_err(sp->dev, "SEV: failed to INIT error %#x\n", error);
+		goto err;
+	}
+
+	/* Display SEV firmware version */
+	status = &psp_master->status_cmd_buf;
+	rc = sev_platform_status(status, &error);
+	if (rc) {
+		dev_err(sp->dev, "SEV: failed to get status error %#x\n", error);
+		goto err;
+	}
+
+	dev_info(sp->dev, "SEV API:%d.%d build:%d\n", status->api_major,
+		 status->api_minor, status->build);
+	return;
+
+err:
+	psp_master = NULL;
+}
+
+void psp_pci_exit(void)
+{
+	if (!psp_master)
+		return;
+
+	sev_platform_shutdown(NULL);
+}