aboutsummaryrefslogtreecommitdiff
path: root/hw/i386
diff options
context:
space:
mode:
Diffstat (limited to 'hw/i386')
-rw-r--r--hw/i386/acpi-build.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 7d880bec4a..2e15f6848e 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2512,6 +2512,34 @@ build_dmar_q35(GArray *table_data, BIOSLinker *linker)
build_header(linker, table_data, (void *)(table_data->data + dmar_start),
"DMAR", table_data->len - dmar_start, 1, NULL, NULL);
}
+
+/*
+ * Windows ACPI Emulated Devices Table
+ * (Version 1.0 - April 6, 2009)
+ * Spec: http://download.microsoft.com/download/7/E/7/7E7662CF-CBEA-470B-A97E-CE7CE0D98DC2/WAET.docx
+ *
+ * Helpful to speedup Windows guests and ignored by others.
+ */
+static void
+build_waet(GArray *table_data, BIOSLinker *linker)
+{
+ int waet_start = table_data->len;
+
+ /* WAET header */
+ acpi_data_push(table_data, sizeof(AcpiTableHeader));
+ /*
+ * Set "ACPI PM timer good" flag.
+ *
+ * Tells Windows guests that our ACPI PM timer is reliable in the
+ * sense that guest can read it only once to obtain a reliable value.
+ * Which avoids costly VMExits caused by guest re-reading it unnecessarily.
+ */
+ build_append_int_noprefix(table_data, 1 << 1 /* ACPI PM timer good */, 4);
+
+ build_header(linker, table_data, (void *)(table_data->data + waet_start),
+ "WAET", table_data->len - waet_start, 1, NULL, NULL);
+}
+
/*
* IVRS table as specified in AMD IOMMU Specification v2.62, Section 5.2
* accessible here http://support.amd.com/TechDocs/48882_IOMMU.pdf
@@ -2859,6 +2887,9 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
machine->nvdimms_state, machine->ram_slots);
}
+ acpi_add_table(table_offsets, tables_blob);
+ build_waet(tables_blob, tables->linker);
+
/* Add tables supplied by user (if any) */
for (u = acpi_table_first(); u; u = acpi_table_next(u)) {
unsigned len = acpi_table_len(u);