[PATCH v3 7/8] x86/sev: Replace occurrences of sev_es_active() with cc_platform_has()

Tom Lendacky
2021-09-08T23:00:43Z

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.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/include/asm/mem_encrypt.h | 2 --
arch/x86/kernel/sev.c | 6 +++---
arch/x86/mm/mem_encrypt.c | 14 ++++----------
arch/x86/realmode/init.c | 3 +--
4 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index f440eebeeb2c..499440781b39 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/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);
bool amd_cc_platform_has(enum cc_attr attr);

#define __bss_decrypted __section(".bss..decrypted")
@@ -75,7 +74,6 @@ 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 bool amd_cc_platform_has(enum cc_attr attr) { return false; }

static inline int __init
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index a6895e440bc3..53a6837d354b 100644
--- a/arch/x86/kernel/sev.c
+++ b/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())
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 22d4e152a6de..47d571a2cd28 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -373,13 +373,6 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
* 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;
-}
-
bool amd_cc_platform_has(enum cc_attr attr)
{
switch (attr) {
@@ -393,7 +386,7 @@ bool amd_cc_platform_has(enum cc_attr attr)
return sev_status & MSR_AMD64_SEV_ENABLED;

case CC_ATTR_GUEST_STATE_ENCRYPT:
- return sev_es_active();
+ return sev_status & MSR_AMD64_SEV_ES_ENABLED;

default:
return false;
@@ -469,7 +462,7 @@ 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");
@@ -488,7 +481,8 @@ 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();
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index c878c5ee5a4c..4a3da7592b99 100644
--- a/arch/x86/realmode/init.c
+++ b/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.
--
2.33.0