commit 4933716beef26b353a1c374d6d8e6dd2e09333af
Author: Michael Tokarev <mjt@tls.msk.ru>
Date:   Sat Apr 5 19:17:54 2014 +0400
Subject: copy OEM ACPI parameters from SLIC table to RSDT
    
When building RSDT table, pick OEM ID fields from uer-supplied SLIC
table instead of using hard-coded QEMU defaults.  This way, say,
OEM version of Windows7 can be run inside qemu using the same OEM
activation as on bare metal, by pointing at system firmware:

  -acpitable file=/sys/firmware/acpi/tables/SLIC

Windows7 requires that OEM ID in RSDT matches those in SLIC to
consider SLIC to be valid.

This is somewhat hackish approach, but it works fairy well in
practice.
    
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 79414b4..a8a3f26 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -53,6 +53,7 @@ static const char unsigned dfl_hdr[ACPI_TABLE_HDR_SIZE - ACPI_TABLE_PFX_SIZE] =
 
 char unsigned *acpi_tables;
 size_t acpi_tables_len;
+size_t slic_table_offset;
 
 static QemuOptsList qemu_acpi_opts = {
     .name = "acpi",
@@ -226,6 +227,10 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen,
     /* recalculate checksum */
     ext_hdr->checksum = acpi_checksum((const char unsigned *)ext_hdr +
                                       ACPI_TABLE_PFX_SIZE, acpi_payload_size);
+
+    if (memcmp(ext_hdr->sig, "SLIC", 4) == 0) {
+       slic_table_offset = acpi_tables_len - acpi_payload_size;
+    }
 }
 
 void acpi_table_add(const QemuOpts *opts, Error **errp)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index a5d3fbf..9e0e16a 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -224,6 +224,8 @@ static void acpi_get_pci_info(PcPciInfo *info)
 #define ACPI_BUILD_TABLE_FILE "etc/acpi/tables"
 #define ACPI_BUILD_RSDP_FILE "etc/acpi/rsdp"
 
+extern size_t slic_table_offset;
+
 static void
 build_header(GArray *linker, GArray *table_data,
              AcpiTableHeader *h, const char *sig, int len, uint8_t rev)
@@ -237,6 +239,11 @@ build_header(GArray *linker, GArray *table_data,
     h->oem_revision = cpu_to_le32(1);
     memcpy(h->asl_compiler_id, ACPI_BUILD_APPNAME4, 4);
     h->asl_compiler_revision = cpu_to_le32(1);
+    if (memcmp(sig, "RSDT", 4) == 0 && slic_table_offset) {
+      /* for win7: OEM info in RSDT and SLIC should be the same */
+      AcpiTableHeader *s = (AcpiTableHeader *)(acpi_tables + slic_table_offset);
+      memcpy(h->oem_id, s->oem_id, 6 + 4 + 4);
+    }
     h->checksum = 0;
     /* Checksum to be filled in by Guest linker */
     bios_linker_loader_add_checksum(linker, ACPI_BUILD_TABLE_FILE,
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1349,6 +1349,8 @@
 For data=, only data
 portion of the table is used, all header information is specified in the
 command line.
+If a SLIC table is supplied to qemu, then the oem_id from the SLIC table
+will be copied into the RSDT table (this is a Debian addition).
 ETEXI
 
 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,