Commit bc6f707f authored by Borislav Petkov (AMD)'s avatar Borislav Petkov (AMD)
Browse files

x86/cc: Add cc_platform_set/_clear() helpers 



Add functionality to set and/or clear different attributes of the
machine as a confidential computing platform. Add the first one too:
whether the machine is running as a host for SEV-SNP guests.

Fixes: 216d106c ("x86/sev: Add SEV-SNP host initialization support")
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Tested-by: default avatarSrikanth Aithal <sraithal@amd.com>
Link: https://lore.kernel.org/r/20240327154317.29909-5-bp@alien8.de
parent 54f5f47b

arch/x86/coco/core.c

+52 −0
Original line number Diff line number Diff line
@@ -20,6 +20,11 @@ 
enum cc_vendor cc_vendor __ro_after_init = CC_VENDOR_NONE;

u64 cc_mask __ro_after_init;



static struct cc_attr_flags {

	__u64 host_sev_snp	: 1,

	      __resv		: 63;

} cc_flags;



static bool noinstr intel_cc_platform_has(enum cc_attr attr)

{

	switch (attr) {
@@ -93,6 +98,9 @@ static bool noinstr amd_cc_platform_has(enum cc_attr attr) 
	case CC_ATTR_GUEST_SEV_SNP:

		return sev_status & MSR_AMD64_SEV_SNP_ENABLED;



	case CC_ATTR_HOST_SEV_SNP:

		return cc_flags.host_sev_snp;



	default:

		return false;

	}
@@ -153,6 +161,50 @@ u64 cc_mkdec(u64 val) 
}

EXPORT_SYMBOL_GPL(cc_mkdec);



static void amd_cc_platform_clear(enum cc_attr attr)

{

	switch (attr) {

	case CC_ATTR_HOST_SEV_SNP:

		cc_flags.host_sev_snp = 0;

		break;

	default:

		break;

	}

}



void cc_platform_clear(enum cc_attr attr)

{

	switch (cc_vendor) {

	case CC_VENDOR_AMD:

		amd_cc_platform_clear(attr);

		break;

	default:

		break;

	}

}



static void amd_cc_platform_set(enum cc_attr attr)

{

	switch (attr) {

	case CC_ATTR_HOST_SEV_SNP:

		cc_flags.host_sev_snp = 1;

		break;

	default:

		break;

	}

}



void cc_platform_set(enum cc_attr attr)

{

	switch (cc_vendor) {

	case CC_VENDOR_AMD:

		amd_cc_platform_set(attr);

		break;

	default:

		break;

	}

}



__init void cc_random_init(void)

{

	/*

include/linux/cc_platform.h

+12 −0
Original line number Diff line number Diff line
@@ -90,6 +90,14 @@ enum cc_attr { 
	 * Examples include TDX Guest.

	 */

	CC_ATTR_HOTPLUG_DISABLED,



	/**

	 * @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host.

	 *

	 * The host kernel is running with the necessary features

	 * enabled to run SEV-SNP guests.

	 */

	CC_ATTR_HOST_SEV_SNP,

};



#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
@@ -107,10 +115,14 @@ enum cc_attr { 
 * * FALSE - Specified Confidential Computing attribute is not active

 */

bool cc_platform_has(enum cc_attr attr);

void cc_platform_set(enum cc_attr attr);

void cc_platform_clear(enum cc_attr attr);



#else	/* !CONFIG_ARCH_HAS_CC_PLATFORM */



static inline bool cc_platform_has(enum cc_attr attr) { return false; }

static inline void cc_platform_set(enum cc_attr attr) { }

static inline void cc_platform_clear(enum cc_attr attr) { }



#endif	/* CONFIG_ARCH_HAS_CC_PLATFORM */