Add RuntimeServices::query_variable_info

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Added `FileHandle::into_directory` and `FileHandle::into_regular_file`.
 - Added `TimeParams`, `Time::invalid`, and `Time::is_invalid`.
+- Added `RuntimeServices::query_variable_info` and `VariableStorageInfo`.
 
 ### Changed
 

src/table/runtime.rs

@@ -60,6 +60,18 @@ pub struct RuntimeServices {
         data_size: usize,
         data: *const u8,
     ) -> !,
+
+    // UEFI 2.0 Capsule Services.
+    update_capsule: usize,
+    query_capsule_capabilities: usize,
+
+    // Miscellaneous UEFI 2.0 Service.
+    query_variable_info: unsafe extern "efiapi" fn(
+        attributes: VariableAttributes,
+        maximum_variable_storage_size: *mut u64,
+        remaining_variable_storage_size: *mut u64,
+        maximum_variable_size: *mut u64,
+    ) -> Status,
 }
 
 impl RuntimeServices {
@@ -227,6 +239,26 @@ impl RuntimeServices {
         }
     }
 
+    /// Get information about UEFI variable storage space for the type
+    /// of variable specified in `attributes`.
+    ///
+    /// See [`VariableStorageInfo`] for details of the information returned.
+    pub fn query_variable_info(
+        &self,
+        attributes: VariableAttributes,
+    ) -> Result<VariableStorageInfo> {
+        let mut info = VariableStorageInfo::default();
+        unsafe {
+            (self.query_variable_info)(
+                attributes,
+                &mut info.maximum_variable_storage_size,
+                &mut info.remaining_variable_storage_size,
+                &mut info.maximum_variable_size,
+            )
+            .into_with_val(|| info)
+        }
+    }
+
     /// Resets the computer.
     pub fn reset(&self, rt: ResetType, status: Status, data: Option<&[u8]>) -> ! {
         let (size, data) = match data {
@@ -619,6 +651,24 @@ impl fmt::Display for VariableKey {
     }
 }
 
+/// Information about UEFI variable storage space returned by
+/// [`RuntimeServices::query_variable_info`]. Note that the data here is
+/// limited to a specific type of variable (as specified by the
+/// `attributes` argument to `query_variable_info`).
+#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
+pub struct VariableStorageInfo {
+    /// Maximum size in bytes of the storage space available for
+    /// variables of the specified type.
+    pub maximum_variable_storage_size: u64,
+
+    /// Remaining size in bytes of the storage space available for
+    /// variables of the specified type.
+    pub remaining_variable_storage_size: u64,
+
+    /// Maximum size of an individual variable of the specified type.
+    pub maximum_variable_size: u64,
+}
+
 /// The type of system reset.
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[repr(u32)]

uefi-test-runner/src/runtime/vars.rs

@@ -46,6 +46,20 @@ fn test_variables(rt: &RuntimeServices) {
     }
 }
 
+fn test_variable_info(rt: &RuntimeServices) {
+    info!(
+        "Storage for non-volatile variabls: {:?}",
+        rt.query_variable_info(VariableAttributes::NON_VOLATILE),
+    );
+    info!(
+        "Storage for volatile runtime variables: {:?}",
+        rt.query_variable_info(
+            VariableAttributes::BOOTSERVICE_ACCESS | VariableAttributes::RUNTIME_ACCESS
+        ),
+    );
+}
+
 pub fn test(rt: &RuntimeServices) {
     test_variables(rt);
+    test_variable_info(rt);
 }