Re: [PATCH v1 2/4] efi_loader: Add OS notifications for SetVariableRT in RAM

On 4/6/24 16:01, Ilias Apalodimas wrote:

Previous patches enable SetVariableRT using a volatile storage backend using EFI_RUNTIME_SERVICES_DATA allocared memory. Since there's no recommendation from the spec on how to notify the OS, add a volatile EFI variable that contains the filename relative to the ESP. OS'es can use that file and update it at runtime

$~ efivar -p -n b2ac5fc9-92b7-4acd-aeac-11e818c3130c-RTStorageVolatile GUID: b2ac5fc9-92b7-4acd-aeac-11e818c3130c Name: "RTStorageVolatile" Attributes: Boot Service Access Runtime Service Access Value: 00000000 75 62 6f 6f 74 65 66 69 2e 76 61 72 00 |ubootefi.var. |

Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org

include/efi_loader.h | 4 ++++ lib/efi_loader/efi_runtime.c | 4 ---- lib/efi_loader/efi_variable.c | 20 ++++++++++++++++++++ 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index 7daca0afba2b..25551fe18948 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -159,6 +159,10 @@ static inline void efi_set_bootdev(const char *dev, const char *devnr, #define EFICONFIG_AUTO_GENERATED_ENTRY_GUID \ EFI_GUID(0x8108ac4e, 0x9f11, 0x4d59, \ 0x85, 0x0e, 0xe2, 0x1a, 0x52, 0x2c, 0x59, 0xb2) +#define U_BOOT_EFI_RT_VAR_FILE_GUID \

• EFI_GUID(0xb2ac5fc9, 0x92b7, 0x4acd, \

•  0xae, 0xac, 0x11, 0xe8, 0x18, 0xc3, 0x13, 0x0c)
  

• /* Use internal device tree when starting UEFI application */ #define EFI_FDT_USE_INTERNAL NULL

diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c index 8ebbea7e5c69..d898ba6c268f 100644 --- a/lib/efi_loader/efi_runtime.c +++ b/lib/efi_loader/efi_runtime.c @@ -127,10 +127,6 @@ efi_status_t efi_init_runtime_supported(void) EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP | EFI_RT_SUPPORTED_CONVERT_POINTER;

• if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE))

• rt_table->runtime_services_supported |=
  

• 	EFI_RT_SUPPORTED_SET_VARIABLE;
  

Why do you want to remove this flag?

Best regards

Heinrich

/* * This value must be synced with efi_runtime_detach_list * as well as efi_runtime_services. diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index f79041e6bedd..f97c8c57f75c 100644 --- a/lib/efi_loader/efi_variable.c +++ b/lib/efi_loader/efi_variable.c @@ -554,6 +554,26 @@ if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE)) { */ void efi_variables_boot_exit_notify(void) {

• const efi_guid_t efi_guid_efi_rt_var_file = U_BOOT_EFI_RT_VAR_FILE_GUID;
• const efi_guid_t rt_prop_guid = EFI_RT_PROPERTIES_TABLE_GUID;
• efi_status_t ret;
• if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE)) {

• struct efi_rt_properties_table *rt_prop =
  

• 	efi_get_configuration_table(&rt_prop_guid);
  

• ret = efi_set_variable_int(u"RTStorageVolatile",
  

• 			   &efi_guid_efi_rt_var_file,
  

• 			   EFI_VARIABLE_BOOTSERVICE_ACCESS |
  

• 			   EFI_VARIABLE_RUNTIME_ACCESS |
  

• 			   EFI_VARIABLE_READ_ONLY,
  

• 			   sizeof(EFI_VAR_FILE_NAME),
  

• 			   EFI_VAR_FILE_NAME, false);
  

• if (ret != EFI_SUCCESS)
  

• 	rt_prop->runtime_services_supported |= ~EFI_RT_SUPPORTED_SET_VARIABLE;
  

• else
  

• 	log_err("Can't RTStorage. SetVariableRT won't be available\n");
  

• } /* Switch variable services functions to runtime version */ efi_runtime_services.get_variable = efi_get_variable_runtime; efi_runtime_services.get_next_variable_name =