x86/coco: Explicitly declare type of confidential computing platform

The kernel derives the confidential computing platform
type it is running as from sme_me_mask on AMD or by using
hv_is_isolation_supported() on HyperV isolation VMs. This detection
process will be more complicated as more platforms get added.

Declare a confidential computing vendor variable explicitly and set it
via cc_set_vendor() on the respective platform.

  [ bp: Massage commit message, fixup HyperV check. ]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220222185740.26228-4-kirill.shutemov@linux.intel.com

diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
index 6a6ffcd..476dcd1 100644 (file)
--- a/arch/x86/coco/core.c
+++ b/arch/x86/coco/core.c
@@ -9,18 +9,15 @@
 
 #include <linux/export.h>
 #include <linux/cc_platform.h>
-#include <linux/mem_encrypt.h>
 
-#include <asm/mshyperv.h>
+#include <asm/coco.h>
 #include <asm/processor.h>
 
-static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
+static enum cc_vendor vendor __ro_after_init;
+
+static bool intel_cc_platform_has(enum cc_attr attr)
 {
-#ifdef CONFIG_INTEL_TDX_GUEST
-       return false;
-#else
        return false;
-#endif
 }
 
 /*
@@ -74,12 +71,20 @@ static bool hyperv_cc_platform_has(enum cc_attr attr)
 
 bool cc_platform_has(enum cc_attr attr)
 {
-       if (sme_me_mask)
+       switch (vendor) {
+       case CC_VENDOR_AMD:
                return amd_cc_platform_has(attr);
-
-       if (hv_is_isolation_supported())
+       case CC_VENDOR_INTEL:
+               return intel_cc_platform_has(attr);
+       case CC_VENDOR_HYPERV:
                return hyperv_cc_platform_has(attr);
-
-       return false;
+       default:
+               return false;
+       }
 }
 EXPORT_SYMBOL_GPL(cc_platform_has);
+
+__init void cc_set_vendor(enum cc_vendor v)
+{
+       vendor = v;
+}

diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h
new file mode 100644 (file)
index 0000000..e49f9dd
--- /dev/null
+++ b/arch/x86/include/asm/coco.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_COCO_H
+#define _ASM_X86_COCO_H
+
+enum cc_vendor {
+       CC_VENDOR_NONE,
+       CC_VENDOR_AMD,
+       CC_VENDOR_HYPERV,
+       CC_VENDOR_INTEL,
+};
+
+void cc_set_vendor(enum cc_vendor v);
+
+#endif /* _ASM_X86_COCO_H */

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 5a99f99..e0a5724 100644 (file)
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -33,6 +33,7 @@
 #include <asm/nmi.h>
 #include <clocksource/hyperv_timer.h>
 #include <asm/numa.h>
+#include <asm/coco.h>
 
 /* Is Linux running as the root partition? */
 bool hv_root_partition;
@@ -344,6 +345,11 @@ static void __init ms_hyperv_init_platform(void)
                 */
                swiotlb_force = SWIOTLB_FORCE;
 #endif
+               /* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
+               if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
+                       if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
+                               cc_set_vendor(CC_VENDOR_HYPERV);
+               }
        }
 
        if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {

diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 3f0abb4..06314ae 100644 (file)
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -44,6 +44,7 @@
 #include <asm/setup.h>
 #include <asm/sections.h>
 #include <asm/cmdline.h>
+#include <asm/coco.h>
 
 #include "mm_internal.h"
 
@@ -565,8 +566,7 @@ void __init sme_enable(struct boot_params *bp)
        } else {
                /* SEV state cannot be controlled by a command line option */
                sme_me_mask = me_mask;
-               physical_mask &= ~sme_me_mask;
-               return;
+               goto out;
        }
 
        /*
@@ -600,6 +600,9 @@ void __init sme_enable(struct boot_params *bp)
                sme_me_mask = 0;
        else
                sme_me_mask = active_by_default ? me_mask : 0;
-
-       physical_mask &= ~sme_me_mask;
+out:
+       if (sme_me_mask) {
+               physical_mask &= ~sme_me_mask;
+               cc_set_vendor(CC_VENDOR_AMD);
+       }
 }