Commit-ID: 07344b15a994acadbe439aa4e75127ed1ccca099
Gitweb: https://git.kernel.org/tip/07344b15a994acadbe439aa4e75127ed1ccca099
Author: Tom Lendacky <[email protected]>
AuthorDate: Tue, 27 Mar 2018 17:07:11 -0500
Committer: Thomas Gleixner <[email protected]>
CommitDate: Wed, 28 Mar 2018 10:42:57 +0200
x86/boot: Fix SEV boot failure from change to __PHYSICAL_MASK_SHIFT
In arch/x86/boot/compressed/kaslr_64.c, CONFIG_AMD_MEM_ENCRYPT support was
initially #undef'd to support SME with minimal effort. When support for
SEV was added, the #undef remained and some minimal support for setting the
encryption bit was added for building identity mapped pagetable entries.
Commit b83ce5ee9147 ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52")
changed __PHYSICAL_MASK_SHIFT from 46 to 52 in support of 5-level paging.
This change resulted in SEV guests failing to boot because the encryption
bit was no longer being automatically masked out. The compressed boot
path now requires sme_me_mask to be defined in order for the pagetable
functions, such as pud_present(), to properly mask out the encryption bit
(currently bit 47) when evaluating pagetable entries.
Add an sme_me_mask variable in arch/x86/boot/compressed/mem_encrypt.S,
which is set when SEV is active, delete the #undef CONFIG_AMD_MEM_ENCRYPT
from arch/x86/boot/compressed/kaslr_64.c and use sme_me_mask when building
the identify mapped pagetable entries.
Fixes: b83ce5ee9147 ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52")
Signed-off-by: Tom Lendacky <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brijesh Singh <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Link:
https://lkml.kernel.org/r/[email protected]
---
arch/x86/boot/compressed/kaslr_64.c | 14 ++++----------
arch/x86/boot/compressed/mem_encrypt.S | 17 ++++++++++-------
arch/x86/boot/compressed/misc.h | 2 +-
3 files changed, 15 insertions(+), 18 deletions(-)
diff --git a/arch/x86/boot/compressed/kaslr_64.c
b/arch/x86/boot/compressed/kaslr_64.c
index b5e5e02f8cde..522d11431433 100644
--- a/arch/x86/boot/compressed/kaslr_64.c
+++ b/arch/x86/boot/compressed/kaslr_64.c
@@ -16,13 +16,6 @@
#define __pa(x) ((unsigned long)(x))
#define __va(x) ((void *)((unsigned long)(x)))
-/*
- * The pgtable.h and mm/ident_map.c includes make use of the SME related
- * information which is not used in the compressed image support. Un-define
- * the SME support to avoid any compile and link errors.
- */
-#undef CONFIG_AMD_MEM_ENCRYPT
-
/* No PAGE_TABLE_ISOLATION support needed either: */
#undef CONFIG_PAGE_TABLE_ISOLATION
@@ -85,13 +78,14 @@ static struct x86_mapping_info mapping_info;
/* Locates and clears a region for a new top level page table. */
void initialize_identity_maps(void)
{
- unsigned long sev_me_mask = get_sev_encryption_mask();
+ /* If running as an SEV guest, the encryption mask is required. */
+ set_sev_encryption_mask();
/* Init mapping_info with run-time function/buffer pointers. */
mapping_info.alloc_pgt_page = alloc_pgt_page;
mapping_info.context = &pgt_data;
- mapping_info.page_flag = __PAGE_KERNEL_LARGE_EXEC | sev_me_mask;
- mapping_info.kernpg_flag = _KERNPG_TABLE | sev_me_mask;
+ mapping_info.page_flag = __PAGE_KERNEL_LARGE_EXEC | sme_me_mask;
+ mapping_info.kernpg_flag = _KERNPG_TABLE;
/*
* It should be impossible for this not to already be true,
diff --git a/arch/x86/boot/compressed/mem_encrypt.S
b/arch/x86/boot/compressed/mem_encrypt.S
index 54f5f6625a73..eaa843a52907 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -88,9 +88,7 @@ ENTRY(get_sev_encryption_bit)
ENDPROC(get_sev_encryption_bit)
.code64
-ENTRY(get_sev_encryption_mask)
- xor %rax, %rax
-
+ENTRY(set_sev_encryption_mask)
#ifdef CONFIG_AMD_MEM_ENCRYPT
push %rbp
push %rdx
@@ -101,9 +99,7 @@ ENTRY(get_sev_encryption_mask)
testl %eax, %eax
jz .Lno_sev_mask
- xor %rdx, %rdx
- bts %rax, %rdx /* Create the encryption mask */
- mov %rdx, %rax /* ... and return it */
+ bts %rax, sme_me_mask(%rip) /* Create the encryption mask */
.Lno_sev_mask:
movq %rbp, %rsp /* Restore original stack pointer */
@@ -112,9 +108,16 @@ ENTRY(get_sev_encryption_mask)
pop %rbp
#endif
+ xor %rax, %rax
ret
-ENDPROC(get_sev_encryption_mask)
+ENDPROC(set_sev_encryption_mask)
.data
enc_bit:
.int 0xffffffff
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ .balign 8
+GLOBAL(sme_me_mask)
+ .quad 0
+#endif
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 4d369c308ed7..9e11be4cae19 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -114,6 +114,6 @@ static inline void console_init(void)
{ }
#endif
-unsigned long get_sev_encryption_mask(void);
+void set_sev_encryption_mask(void);
#endif
