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-rw-r--r--arch/x86/boot/compressed/ident_map_64.c3
-rw-r--r--arch/x86/boot/compressed/misc.h2
-rw-r--r--arch/x86/boot/compressed/sev.c21
3 files changed, 25 insertions, 1 deletions
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index 99348ee7999b..44c350d627c7 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -163,8 +163,9 @@ void initialize_identity_maps(void *rmode)
cmdline = get_cmd_line_ptr();
kernel_add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
+ sev_prep_identity_maps(top_level_pgt);
+
/* Load the new page-table. */
- sev_verify_cbit(top_level_pgt);
write_cr3(top_level_pgt);
}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index aae2722c6e9a..75d284ec763f 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -127,6 +127,7 @@ void sev_es_shutdown_ghcb(void);
extern bool sev_es_check_ghcb_fault(unsigned long address);
void snp_set_page_private(unsigned long paddr);
void snp_set_page_shared(unsigned long paddr);
+void sev_prep_identity_maps(unsigned long top_level_pgt);
#else
static inline void sev_enable(struct boot_params *bp) { }
static inline void sev_es_shutdown_ghcb(void) { }
@@ -136,6 +137,7 @@ static inline bool sev_es_check_ghcb_fault(unsigned long address)
}
static inline void snp_set_page_private(unsigned long paddr) { }
static inline void snp_set_page_shared(unsigned long paddr) { }
+static inline void sev_prep_identity_maps(unsigned long top_level_pgt) { }
#endif
/* acpi.c */
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index dd3cf55696d4..1e4930ce2c95 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -478,3 +478,24 @@ bool snp_init(struct boot_params *bp)
return true;
}
+
+void sev_prep_identity_maps(unsigned long top_level_pgt)
+{
+ /*
+ * The Confidential Computing blob is used very early in uncompressed
+ * kernel to find the in-memory CPUID table to handle CPUID
+ * instructions. Make sure an identity-mapping exists so it can be
+ * accessed after switchover.
+ */
+ if (sev_snp_enabled()) {
+ unsigned long cc_info_pa = boot_params->cc_blob_address;
+ struct cc_blob_sev_info *cc_info;
+
+ kernel_add_identity_map(cc_info_pa, cc_info_pa + sizeof(*cc_info));
+
+ cc_info = (struct cc_blob_sev_info *)cc_info_pa;
+ kernel_add_identity_map(cc_info->cpuid_phys, cc_info->cpuid_phys + cc_info->cpuid_len);
+ }
+
+ sev_verify_cbit(top_level_pgt);
+}