diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 1d8c645ed3..c75f73ebb1 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -341,7 +341,7 @@ build_fadt(GArray *table_data, BIOSLinker *linker, AcpiPmInfo *pm,
     AcpiFadtDescriptorRev3 *fadt = acpi_data_push(table_data, sizeof(*fadt));
     unsigned fw_ctrl_offset = (char *)&fadt->firmware_ctrl - table_data->data;
     unsigned dsdt_entry_offset = (char *)&fadt->dsdt - table_data->data;
-    unsigned xdsdt_entry_offset = (char *)&fadt->Xdsdt - table_data->data;
+    unsigned xdsdt_entry_offset = (char *)&fadt->x_dsdt - table_data->data;
 
     /* FACS address to be filled by Guest linker */
     bios_linker_loader_add_pointer(linker,
@@ -354,7 +354,7 @@ build_fadt(GArray *table_data, BIOSLinker *linker, AcpiPmInfo *pm,
         ACPI_BUILD_TABLE_FILE, dsdt_entry_offset, sizeof(fadt->dsdt),
         ACPI_BUILD_TABLE_FILE, dsdt_tbl_offset);
     bios_linker_loader_add_pointer(linker,
-        ACPI_BUILD_TABLE_FILE, xdsdt_entry_offset, sizeof(fadt->Xdsdt),
+        ACPI_BUILD_TABLE_FILE, xdsdt_entry_offset, sizeof(fadt->x_dsdt),
         ACPI_BUILD_TABLE_FILE, dsdt_tbl_offset);
 
     build_header(linker, table_data,
diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
index 293ee4524b..93e1ebad62 100644
--- a/include/hw/acpi/acpi-defs.h
+++ b/include/hw/acpi/acpi-defs.h
@@ -144,8 +144,8 @@ typedef struct AcpiTableHeader AcpiTableHeader;
     /* ARM-Specific Boot Flags (see below for individual flags) (ACPI 5.1) */ \
     uint16_t arm_boot_flags; \
     uint8_t minor_revision;  /* FADT Minor Revision (ACPI 5.1) */ \
-    uint64_t Xfacs;          /* 64-bit physical address of FACS */ \
-    uint64_t Xdsdt;          /* 64-bit physical address of DSDT */ \
+    uint64_t x_facs;          /* 64-bit physical address of FACS */ \
+    uint64_t x_dsdt;          /* 64-bit physical address of DSDT */ \
     /* 64-bit Extended Power Mgt 1a Event Reg Blk address */ \
     struct AcpiGenericAddress xpm1a_event_block; \
     /* 64-bit Extended Power Mgt 1b Event Reg Blk address */ \
diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
index 9c96a67053..bdef3b9cee 100644
--- a/tests/bios-tables-test.c
+++ b/tests/bios-tables-test.c
@@ -175,8 +175,8 @@ static void test_acpi_fadt_table(test_data *data)
     ACPI_READ_FIELD(fadt_table->reset_value, addr);
     ACPI_READ_FIELD(fadt_table->arm_boot_flags, addr);
     ACPI_READ_FIELD(fadt_table->minor_revision, addr);
-    ACPI_READ_FIELD(fadt_table->Xfacs, addr);
-    ACPI_READ_FIELD(fadt_table->Xdsdt, addr);
+    ACPI_READ_FIELD(fadt_table->x_facs, addr);
+    ACPI_READ_FIELD(fadt_table->x_dsdt, addr);
     ACPI_READ_GENERIC_ADDRESS(fadt_table->xpm1a_event_block, addr);
     ACPI_READ_GENERIC_ADDRESS(fadt_table->xpm1b_event_block, addr);
     ACPI_READ_GENERIC_ADDRESS(fadt_table->xpm1a_control_block, addr);