feat: add scsi mode sense operation to detect write protection

MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c

@@ -196,6 +196,68 @@ ScsiDiskDriverBindingSupported (
   return Status;
 }
 
+// MU_CHANGE Begin: Add function to check whether the disk is write protected
+
+/**
+y * Check whether the SCSI disk is write protected.
+ *
+ * @param ScsiDiskDevice      The SCSI disk device.
+ * @param WriteProtectionEnabled  A pointer to a boolean that will be set to TRUE if the disk is write protected, FALSE otherwise.
+ *
+ * @return EFI_SUCCESS           The operation completed successfully.
+ * @return EFI_INVALID_PARAMETER One of the input parameters was invalid.
+ * @return other                 An error occurred while executing the SCSI command.
+ */
+STATIC
+EFI_STATUS
+IsWriteProtected (
+  IN OUT SCSI_DISK_DEV  *ScsiDiskDevice,
+  OUT BOOLEAN           *WriteProtectionEnabled
+  )
+{
+  EFI_STATUS                       Status;
+  EFI_SCSI_IO_SCSI_REQUEST_PACKET  CommandPacket;
+  UINT8                            Cdb[6];
+  UINT8                            DataBuffer[64];
+
+  if ((ScsiDiskDevice == NULL) || (WriteProtectionEnabled == NULL) || (ScsiDiskDevice->ScsiIo == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  //
+  // Initialize SCSI REQUEST_PACKET and 6-byte Cdb
+  //
+  ZeroMem (&CommandPacket, sizeof (CommandPacket));
+  ZeroMem (Cdb, sizeof (Cdb));
+
+  // Initialize output parameter to default value
+  *WriteProtectionEnabled = FALSE;
+
+  Cdb[0] = ATA_CMD_MODE_SENSE6;
+  Cdb[1] = 0b1000;                         // Setting the bit for Disable Block Descriptor
+  Cdb[2] = ATA_PAGE_CODE_RETURN_ALL_PAGES;
+  Cdb[4] = sizeof (DataBuffer);
+
+  CommandPacket.Timeout          = SCSI_DISK_TIMEOUT;
+  CommandPacket.Cdb              = Cdb;
+  CommandPacket.CdbLength        = (UINT8)sizeof (Cdb);
+  CommandPacket.InDataBuffer     = &DataBuffer;
+  CommandPacket.InTransferLength = sizeof (DataBuffer);
+
+  Status = ScsiDiskDevice->ScsiIo->ExecuteScsiCommand (ScsiDiskDevice->ScsiIo, &CommandPacket, NULL);
+
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  // Mode Sense 6 Byte Command returns the Write Protection status in the 3rd byte
+  // Bit 7 of the 3rd byte indicates the Write Protection status
+  *WriteProtectionEnabled = (DataBuffer[2] & 0x80) != 0;
+  return EFI_SUCCESS;
+}
+
+// MU_CHANGE End: Add function to check whether the disk is write protected
+
 /**
   Start this driver on ControllerHandle.
 
@@ -234,6 +296,8 @@ ScsiDiskDriverBindingStart (
   CHAR8                 VendorStr[VENDOR_IDENTIFICATION_LENGTH + 1];
   CHAR8                 ProductStr[PRODUCT_IDENTIFICATION_LENGTH + 1];
   CHAR16                DeviceStr[VENDOR_IDENTIFICATION_LENGTH + PRODUCT_IDENTIFICATION_LENGTH + 2];
+  // MU_CHANGE: Add variable to check whether the disk is write protected
+  BOOLEAN  WriteProtectionEnabled = FALSE;
 
   MustReadCapacity = TRUE;
 
@@ -297,6 +361,20 @@ ScsiDiskDriverBindingStart (
       break;
   }
 
+  // MU_CHANGE Begin: Check whether the disk is write protected and set the ReadOnly flag accordingly
+  if (ScsiDiskDevice->DeviceType == EFI_SCSI_TYPE_DISK) {
+    Status = IsWriteProtected (ScsiDiskDevice, &WriteProtectionEnabled);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_ERROR, "ScsiDisk: IsWriteProtected() fails. Status = %r\n", Status));
+    }
+
+    if (WriteProtectionEnabled) {
+      ScsiDiskDevice->BlkIo.Media->ReadOnly = TRUE;
+    }
+  }
+
+  // MU_CHANGE End: Check whether the disk is write protected and set the ReadOnly flag accordingly
+
   //
   // The Sense Data Array's initial size is 6
   //

MdePkg/Include/IndustryStandard/Atapi.h

@@ -503,6 +503,8 @@ typedef union {
 #define ATA_CMD_PREVENT_ALLOW_MEDIA_REMOVAL  0x1E              ///< defined in ATAPI Removable Rewritable Media Devices
 #define ATA_CMD_MODE_SELECT                  0x55              ///< defined in ATAPI Removable Rewritable Media Devices
 
+// MU_CHANGE: Add some definitions for MODE SENSE (6-Byte) command
+#define ATA_CMD_MODE_SENSE6                         0x1A       ///< defined in ATAPI Removable Rewritable Media Devices
 #define ATA_CMD_MODE_SENSE                          0x5A       ///< defined in ATAPI Removable Rewritable Media Devices
 #define ATA_PAGE_CODE_READ_WRITE_ERROR              0x01       ///< defined in ATAPI Removable Rewritable Media Devices
 #define ATA_PAGE_CODE_CACHING_PAGE                  0x08       ///< defined in ATAPI Removable Rewritable Media Devices