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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
This commit is contained in:
Tom Lendacky 2021-09-08 17:58:38 -05:00 committed by Borislav Petkov
parent 4d96f91091
commit 6283f2effb
4 changed files with 7 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/mem_encrypt.h
View File

@ -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; }

6
arch/x86/kernel/sev.c
View File

@ -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())

24
arch/x86/mm/mem_encrypt.c
View File

@ -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();

3
arch/x86/realmode/init.c
View File

@ -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.