[Xen-devel] [PATCH v9 16/38] efi: Add an EFI table address match function

[Tom Lendacky <thomas.lendacky@xxxxxxx>]

Add a function that will determine if a supplied physical address matches
the address of an EFI table.

Reviewed-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
 drivers/firmware/efi/efi.c |   33 +++++++++++++++++++++++++++++++++
 include/linux/efi.h        |    7 +++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 045d6d3..69d4d13 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -55,6 +55,25 @@ struct efi __read_mostly efi = {
 };
 EXPORT_SYMBOL(efi);
 
+static unsigned long *efi_tables[] = {
+       &efi.mps,
+       &efi.acpi,
+       &efi.acpi20,
+       &efi.smbios,
+       &efi.smbios3,
+       &efi.sal_systab,
+       &efi.boot_info,
+       &efi.hcdp,
+       &efi.uga,
+       &efi.uv_systab,
+       &efi.fw_vendor,
+       &efi.runtime,
+       &efi.config_table,
+       &efi.esrt,
+       &efi.properties_table,
+       &efi.mem_attr_table,
+};
+
 static bool disable_runtime;
 static int __init setup_noefi(char *arg)
 {
@@ -855,6 +874,20 @@ int efi_status_to_err(efi_status_t status)
        return err;
 }
 
+bool efi_is_table_address(unsigned long phys_addr)
+{
+       unsigned int i;
+
+       if (phys_addr == EFI_INVALID_TABLE_ADDR)
+               return false;
+
+       for (i = 0; i < ARRAY_SIZE(efi_tables); i++)
+               if (*(efi_tables[i]) == phys_addr)
+                       return true;
+
+       return false;
+}
+
 #ifdef CONFIG_KEXEC
 static int update_efi_random_seed(struct notifier_block *nb,
                                  unsigned long code, void *unused)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8269bcb..8e24f09 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1091,6 +1091,8 @@ static inline bool efi_enabled(int feature)
        return test_bit(feature, &efi.flags) != 0;
 }
 extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
+
+extern bool efi_is_table_address(unsigned long phys_addr);
 #else
 static inline bool efi_enabled(int feature)
 {
@@ -1104,6 +1106,11 @@ static inline bool efi_enabled(int feature)
 {
        return false;
 }
+
+static inline bool efi_is_table_address(unsigned long phys_addr)
+{
+       return false;
+}
 #endif
 
 extern int efi_status_to_err(efi_status_t status);


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