Commit f5db8841 authored by Brijesh Singh's avatar Brijesh Singh Committed by Borislav Petkov (AMD)
Browse files

crypto: ccp: Add the SNP_PLATFORM_STATUS command 



This command is used to query the SNP platform status. See the SEV-SNP
spec for more details.

Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarAshish Kalra <ashish.kalra@amd.com>
Signed-off-by: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240126041126.1927228-24-michael.roth@amd.com
parent c3b86e61

Documentation/virt/coco/sev-guest.rst

+27 −0
Original line number Diff line number Diff line
@@ -67,6 +67,22 @@ counter (e.g. counter overflow), then -EIO will be returned. 
                };

        };



The host ioctls are issued to a file descriptor of the /dev/sev device.

The ioctl accepts the command ID/input structure documented below.



::

        struct sev_issue_cmd {

                /* Command ID */

                __u32 cmd;



                /* Command request structure */

                __u64 data;



                /* Firmware error code on failure (see psp-sev.h) */

                __u32 error;

        };





2.1 SNP_GET_REPORT

------------------
@@ -124,6 +140,17 @@ be updated with the expected value. 


See GHCB specification for further detail on how to parse the certificate blob.



2.4 SNP_PLATFORM_STATUS

-----------------------

:Technology: sev-snp

:Type: hypervisor ioctl cmd

:Parameters (out): struct sev_user_data_snp_status

:Returns (out): 0 on success, -negative on error



The SNP_PLATFORM_STATUS command is used to query the SNP platform status. The

status includes API major, minor version and more. See the SEV-SNP

specification for further details.



3. SEV-SNP CPUID Enforcement

============================

drivers/crypto/ccp/sev-dev.c

+52 −0
Original line number Diff line number Diff line
@@ -1941,6 +1941,55 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable) 
	return ret;

}



static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)

{

	struct sev_device *sev = psp_master->sev_data;

	struct sev_data_snp_addr buf;

	struct page *status_page;

	void *data;

	int ret;



	if (!sev->snp_initialized || !argp->data)

		return -EINVAL;



	status_page = alloc_page(GFP_KERNEL_ACCOUNT);

	if (!status_page)

		return -ENOMEM;



	data = page_address(status_page);



	/*

	 * Firmware expects status page to be in firmware-owned state, otherwise

	 * it will report firmware error code INVALID_PAGE_STATE (0x1A).

	 */

	if (rmp_mark_pages_firmware(__pa(data), 1, true)) {

		ret = -EFAULT;

		goto cleanup;

	}



	buf.address = __psp_pa(data);

	ret = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &argp->error);



	/*

	 * Status page will be transitioned to Reclaim state upon success, or

	 * left in Firmware state in failure. Use snp_reclaim_pages() to

	 * transition either case back to Hypervisor-owned state.

	 */

	if (snp_reclaim_pages(__pa(data), 1, true))

		return -EFAULT;



	if (ret)

		goto cleanup;



	if (copy_to_user((void __user *)argp->data, data,

			 sizeof(struct sev_user_data_snp_status)))

		ret = -EFAULT;



cleanup:

	__free_pages(status_page, 0);

	return ret;

}



static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)

{

	void __user *argp = (void __user *)arg;
@@ -1992,6 +2041,9 @@ static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg) 
	case SEV_GET_ID2:

		ret = sev_ioctl_do_get_id2(&input);

		break;

	case SNP_PLATFORM_STATUS:

		ret = sev_ioctl_do_snp_platform_status(&input);

		break;

	default:

		ret = -EINVAL;

		goto out;

include/uapi/linux/psp-sev.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ enum { 
	SEV_PEK_CERT_IMPORT,

	SEV_GET_ID,	/* This command is deprecated, use SEV_GET_ID2 */

	SEV_GET_ID2,

	SNP_PLATFORM_STATUS,



	SEV_MAX,

};