x86/sev: Replace occurrences of sev_es_active() with cc_platform_has()

Replace uses of sev_es_active() with the more generic cc_platform_has()
using CC_ATTR_GUEST_STATE_ENCRYPT. If future support is added for other
memory encyrption techonologies, the use of CC_ATTR_GUEST_STATE_ENCRYPT
can be updated, as required.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-8-bp@alien8.de

Author: tlendacky

arch/x86/include/asm/mem_encrypt.h

@@ -51,7 +51,6 @@ void __init mem_encrypt_free_decrypted_mem(void);
 void __init mem_encrypt_init(void);
 
 void __init sev_es_init_vc_handling(void);
-bool sev_es_active(void);
 
 #define __bss_decrypted __section(".bss..decrypted")
 
@@ -74,7 +73,6 @@ static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }
 static inline void __init sme_enable(struct boot_params *bp) { }
 
 static inline void sev_es_init_vc_handling(void) { }
-static inline bool sev_es_active(void) { return false; }
 
 static inline int __init
 early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }

arch/x86/kernel/sev.c

@@ -11,7 +11,7 @@
 
 #include <linux/sched/debug.h>	/* For show_regs() */
 #include <linux/percpu-defs.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
 #include <linux/printk.h>
 #include <linux/mm_types.h>
 #include <linux/set_memory.h>
@@ -615,7 +615,7 @@ int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
 	int cpu;
 	u64 pfn;
 
-	if (!sev_es_active())
+	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
 		return 0;
 
 	pflags = _PAGE_NX | _PAGE_RW;
@@ -774,7 +774,7 @@ void __init sev_es_init_vc_handling(void)
 
 	BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE);
 
-	if (!sev_es_active())
+	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
 		return;
 
 	if (!sev_es_check_cpu_features())

arch/x86/mm/mem_encrypt.c

@@ -361,25 +361,6 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
 	return early_set_memory_enc_dec(vaddr, size, true);
 }
 
-/*
- * SME and SEV are very similar but they are not the same, so there are
- * times that the kernel will need to distinguish between SME and SEV. The
- * cc_platform_has() function is used for this.  When a distinction isn't
- * needed, the CC_ATTR_MEM_ENCRYPT attribute can be used.
- *
- * The trampoline code is a good example for this requirement.  Before
- * paging is activated, SME will access all memory as decrypted, but SEV
- * will access all memory as encrypted.  So, when APs are being brought
- * up under SME the trampoline area cannot be encrypted, whereas under SEV
- * the trampoline area must be encrypted.
- */
-
-/* Needs to be called from non-instrumentable code */
-bool noinstr sev_es_active(void)
-{
-	return sev_status & MSR_AMD64_SEV_ES_ENABLED;
-}
-
 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
 bool force_dma_unencrypted(struct device *dev)
 {
@@ -449,7 +430,7 @@ static void print_mem_encrypt_feature_info(void)
 		pr_cont(" SEV");
 
 	/* Encrypted Register State */
-	if (sev_es_active())
+	if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
 		pr_cont(" SEV-ES");
 
 	pr_cont("\n");
@@ -468,7 +449,8 @@ void __init mem_encrypt_init(void)
 	 * With SEV, we need to unroll the rep string I/O instructions,
 	 * but SEV-ES supports them through the #VC handler.
 	 */
-	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) && !sev_es_active())
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) &&
+	    !cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
 		static_branch_enable(&sev_enable_key);
 
 	print_mem_encrypt_feature_info();

arch/x86/realmode/init.c

@@ -2,7 +2,6 @@
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/memblock.h>
-#include <linux/mem_encrypt.h>
 #include <linux/cc_platform.h>
 #include <linux/pgtable.h>
 
@@ -48,7 +47,7 @@ static void sme_sev_setup_real_mode(struct trampoline_header *th)
 	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
 		th->flags |= TH_FLAGS_SME_ACTIVE;
 
-	if (sev_es_active()) {
+	if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) {
 		/*
 		 * Skip the call to verify_cpu() in secondary_startup_64 as it
 		 * will cause #VC exceptions when the AP can't handle them yet.