[Qemu-devel] [PATCH v4] Hvmloader: Modify ACPI to only supply _EJ0 methods for PCIslots that support hotplug by runtime patching

[arei.gonglei]

From: Gonglei <address@hidden>

In Xen platform, after using upstream qemu, the all of pci devices
will show hotplug in the windows guest, no matter whether they can
be hotpluged. It is unfriendly. The PCI devices that can not be
hotpluged are hidden by modifing the DSDT entries of PCI slots when runtime.

This is done by:
 - Rename _EJ0 methods for PCI slots in DSDT to EJ0_:note that
   this has the same checksum, but is ignored by OSPM.
 - At compile time, look for these methods in ASL source,
   find the matching AML, and store the offsets of these methods
   in a table named aml_ej0_data.
 - At run time, go over aml_ej0_data, check which slots not support
   hotplug and patch the ACPI table, replacing _EJ0 with EJ0_.

Cc: Michael S. Tsirkin <address@hidden>
Cc: Johannes Krampf <address@hidden>
Cc: Kevin O'Connor <address@hidden>
Signed-off-by: Gaowei <address@hidden>
Signed-off-by: Gonglei <address@hidden>
---
v4->v3:
 - adjust the code style by Ian Campbell's suggestion
 - get permission of Michael, Johannes and Kevin for two python
   scripts being used as "GPLv2 or later" 
v3->v2:
 - reformat on the latest master
v2->v1:
 - adjust the code style by Jan Beulich's suggestion

 tools/firmware/hvmloader/acpi/Makefile             |  37 ++-
 tools/firmware/hvmloader/acpi/acpi2_0.h            |   4 +
 tools/firmware/hvmloader/acpi/build.c              |  22 ++
 tools/firmware/hvmloader/acpi/dsdt.asl             |   1 +
 tools/firmware/hvmloader/acpi/mk_dsdt.c            |  20 +-
 tools/firmware/hvmloader/ovmf.c                    |   6 +-
 tools/firmware/hvmloader/rombios.c                 |   4 +
 tools/firmware/hvmloader/seabios.c                 |   8 +
 tools/firmware/hvmloader/tools/acpi_extract.py     | 308 +++++++++++++++++++++
 .../hvmloader/tools/acpi_extract_preprocess.py     |  41 +++
 10 files changed, 437 insertions(+), 14 deletions(-)
 create mode 100644 tools/firmware/hvmloader/tools/acpi_extract.py
 create mode 100644 tools/firmware/hvmloader/tools/acpi_extract_preprocess.py

diff --git a/tools/firmware/hvmloader/acpi/Makefile 
b/tools/firmware/hvmloader/acpi/Makefile
index 2c50851..fad1cf5 100644
--- a/tools/firmware/hvmloader/acpi/Makefile
+++ b/tools/firmware/hvmloader/acpi/Makefile
@@ -24,30 +24,45 @@ OBJS  = $(patsubst %.c,%.o,$(C_SRC))
 CFLAGS += $(CFLAGS_xeninclude)
 
 vpath iasl $(PATH)
+
+.DELETE_ON_ERROR: $(filter dsdt_%.c,$(C_SRC))
+
 all: acpi.a
 
 ssdt_s3.h ssdt_s4.h ssdt_pm.h ssdt_tpm.h: %.h: %.asl iasl
        iasl -vs -p $* -tc $<
-       sed -e 's/AmlCode/$*/g' $*.hex >$@
+       sed -e 's/AmlCode/$*/g' $*.hex >address@hidden
+       $(call move-if-changed,address@hidden $@)
        rm -f $*.hex $*.aml
 
 mk_dsdt: mk_dsdt.c
-       $(HOSTCC) $(HOSTCFLAGS) $(CFLAGS_xeninclude) -o $@ mk_dsdt.c
+       $(HOSTCC) $(HOSTCFLAGS) $(CFLAGS_xeninclude) -g -o $@ mk_dsdt.c
 
 dsdt_anycpu_qemu_xen.asl: dsdt.asl mk_dsdt
-       awk 'NR > 1 {print s} {s=$$0}' $< > $@
-       ./mk_dsdt --dm-version qemu-xen >> $@
+       awk 'NR > 1 {print s} {s=$$0}' $< > address@hidden
+       sed -i 's/AmlCode/dsdt_anycpu_qemu_xen/g' address@hidden
+       ./mk_dsdt --dm-version qemu-xen --asl-name dsdt_anycpu_qemu_xen 
>>address@hidden
+       $(call move-if-changed,address@hidden $@)
 
 # NB. awk invocation is a portable alternative to 'head -n -1'
 dsdt_%cpu.asl: dsdt.asl mk_dsdt
-       awk 'NR > 1 {print s} {s=$$0}' $< > $@
-       ./mk_dsdt --maxcpu $*  >> $@
+       awk 'NR > 1 {print s} {s=$$0}' $< > address@hidden
+       sed -i 's/AmlCode/dsdt_$*cpu/g' address@hidden
+       ./mk_dsdt --maxcpu $*  >> address@hidden
+       $(call move-if-changed,address@hidden $@)
 
 $(filter dsdt_%.c,$(C_SRC)): %.c: iasl %.asl
-       iasl -vs -p $* -tc $*.asl
-       sed -e 's/AmlCode/$*/g' $*.hex >$@
-       echo "int $*_len=sizeof($*);" >>$@
-       rm -f $*.aml $*.hex
+       cpp -P $*.asl > $*.asl.i.orig
+       $(PYTHON) ../tools/acpi_extract_preprocess.py $*.asl.i.orig > $*.asl.i
+       iasl -vs -l -tc -p $* $*.asl.i
+       $(PYTHON) ../tools/acpi_extract.py $*.lst > address@hidden
+       echo "int $*_len=sizeof($*);" >>address@hidden
+       if grep -q "$*_aml_ej0_name" address@hidden; then \
+               echo "int 
$*_aml_ej0_name_len=sizeof($*_aml_ej0_name)/sizeof($*_aml_ej0_name[0]);" 
>>address@hidden;fi
+       if grep -q "$*_aml_adr_dword" address@hidden; then \
+               echo "int 
$*_aml_adr_dword_len=sizeof($*_aml_adr_dword)/sizeof($*_aml_adr_dword[0]);" 
>>address@hidden;fi
+       $(call move-if-changed,address@hidden $@)
+       rm -f $*.aml $*.hex $*.asl.i.orig $*.asl.i $*.lst
 
 iasl:
        @echo
@@ -64,7 +79,7 @@ acpi.a: $(OBJS)
 
 clean:
        rm -rf *.a *.o $(IASL_VER) $(IASL_VER).tar.gz $(DEPS)
-       rm -rf ssdt_*.h dsdt*.c *~ *.aml *.hex mk_dsdt dsdt_*.asl
+       rm -rf ssdt_*.h dsdt*.c *~ *.aml *.hex mk_dsdt dsdt_*.asl *.asl.i 
*.asl.i.orig *.lst *.tmp
 
 install: all
 
diff --git a/tools/firmware/hvmloader/acpi/acpi2_0.h 
b/tools/firmware/hvmloader/acpi/acpi2_0.h
index 7b22d80..4ba3957 100644
--- a/tools/firmware/hvmloader/acpi/acpi2_0.h
+++ b/tools/firmware/hvmloader/acpi/acpi2_0.h
@@ -396,6 +396,10 @@ struct acpi_config {
     int dsdt_anycpu_len;
     unsigned char *dsdt_15cpu;
     int dsdt_15cpu_len;
+    unsigned short *aml_ej0_name;
+    unsigned short *aml_adr_dword;
+    int aml_ej0_name_len;
+    int aml_adr_dword_len;
 };
 
 void acpi_build_tables(struct acpi_config *config, unsigned int physical);
diff --git a/tools/firmware/hvmloader/acpi/build.c 
b/tools/firmware/hvmloader/acpi/build.c
index f1dd3f0..493eaea 100644
--- a/tools/firmware/hvmloader/acpi/build.c
+++ b/tools/firmware/hvmloader/acpi/build.c
@@ -30,6 +30,9 @@
 #define align16(sz)        (((sz) + 15) & ~15)
 #define fixed_strcpy(d, s) strncpy((d), (s), sizeof(d))
 
+/* It is a ABI by qemu for showing the hotplugging ability of PCI devices */
+#define PCI_RMV_BASE 0xae0c
+
 extern struct acpi_20_rsdp Rsdp;
 extern struct acpi_20_rsdt Rsdt;
 extern struct acpi_20_xsdt Xsdt;
@@ -404,6 +407,7 @@ void acpi_build_tables(struct acpi_config *config, unsigned 
int physical)
     unsigned char       *dsdt;
     unsigned long        secondary_tables[ACPI_MAX_SECONDARY_TABLES];
     int                  nr_secondaries, i;
+    unsigned int         rmvc_pcrm;
 
     /* Allocate and initialise the acpi info area. */
     mem_hole_populate_ram(ACPI_INFO_PHYSICAL_ADDRESS >> PAGE_SHIFT, 1);
@@ -440,6 +444,24 @@ void acpi_build_tables(struct acpi_config *config, 
unsigned int physical)
         memcpy(dsdt, config->dsdt_anycpu, config->dsdt_anycpu_len);
         nr_processor_objects = HVM_MAX_VCPUS;
     }
+    if ((config->aml_adr_dword_len == config->aml_ej0_name_len) && 
config->aml_ej0_name_len)
+    {
+        rmvc_pcrm = inl(PCI_RMV_BASE);
+        for (i = 0;  i < config->aml_adr_dword_len; i++ ) {
+            /* Slot is in byte 2 in _ADR */
+            unsigned char slot = dsdt[config->aml_adr_dword[i] + 2] & 0x1F;
+            /* Sanity check */
+            if (memcmp(dsdt + config->aml_ej0_name[i], "_EJ0", 4)){
+                /*something is wrong, stop modifing the table*/
+                printf("check _EJ0 in table failed\n");
+                goto modify_ej0_out;
+            }
+            if (!(rmvc_pcrm & (0x1 << slot)))
+                memcpy(dsdt + config->aml_ej0_name[i], "EJ0_", 4);
+        }
+    }
+
+modify_ej0_out:
 
     /*
      * N.B. ACPI 1.0 operating systems may not handle FADT with revision 2
diff --git a/tools/firmware/hvmloader/acpi/dsdt.asl 
b/tools/firmware/hvmloader/acpi/dsdt.asl
index 247a8ad..1e7695b 100644
--- a/tools/firmware/hvmloader/acpi/dsdt.asl
+++ b/tools/firmware/hvmloader/acpi/dsdt.asl
@@ -16,6 +16,7 @@
  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  * Place - Suite 330, Boston, MA 02111-1307 USA.
  */
+ACPI_EXTRACT_ALL_CODE AmlCode
 
 DefinitionBlock ("DSDT.aml", "DSDT", 2, "Xen", "HVM", 0)
 {
diff --git a/tools/firmware/hvmloader/acpi/mk_dsdt.c 
b/tools/firmware/hvmloader/acpi/mk_dsdt.c
index a4b693b..ec55257 100644
--- a/tools/firmware/hvmloader/acpi/mk_dsdt.c
+++ b/tools/firmware/hvmloader/acpi/mk_dsdt.c
@@ -83,6 +83,7 @@ static void decision_tree(
 static struct option options[] = {
     { "maxcpu", 1, 0, 'c' },
     { "dm-version", 1, 0, 'q' },
+    { "asl-name", 1, 0, 'a' },
     { 0, 0, 0, 0 }
 };
 
@@ -90,7 +91,7 @@ int main(int argc, char **argv)
 {
     unsigned int slot, dev, intx, link, cpu, max_cpus = HVM_MAX_VCPUS;
     dm_version dm_version = QEMU_XEN_TRADITIONAL;
-
+    char *asl_name_string = NULL;
     for ( ; ; )
     {
         int opt = getopt_long(argc, argv, "", options, NULL);
@@ -125,6 +126,16 @@ int main(int argc, char **argv)
                 return -1;
             }
             break;
+        case 'a':
+            if (optarg) {
+                asl_name_string = malloc(strlen(optarg)+1);
+                if (!asl_name_string) {
+                    fprintf(stderr, "not enough memory for copy string %s.\n", 
optarg);
+                    return -1;
+                }
+                memcpy(asl_name_string, optarg, strlen(optarg)+1);
+            }
+            break;
         default:
             return -1;
         }
@@ -372,7 +383,11 @@ int main(int argc, char **argv)
         /* hotplug_slot */
         for (slot = 1; slot <= 31; slot++) {
             push_block("Device", "S%i", slot); {
+                if (asl_name_string)
+                    printf("ACPI_EXTRACT_NAME_DWORD_CONST %s_aml_adr_dword\n", 
asl_name_string);
                 stmt("Name", "_ADR, %#06x0000", slot);
+                if (asl_name_string)
+                    printf("ACPI_EXTRACT_METHOD_STRING %s_aml_ej0_name\n", 
asl_name_string);
                 push_block("Method", "_EJ0,1"); {
                     stmt("Store", "ShiftLeft(1, %#06x), B0EJ", slot);
                     stmt("Return", "0x0");
@@ -450,7 +465,8 @@ int main(int argc, char **argv)
 
     pop_block();
     /**** DSDT DefinitionBlock end ****/
-
+    if (asl_name_string)
+        free(asl_name_string);
     return 0;
 }
 
diff --git a/tools/firmware/hvmloader/ovmf.c b/tools/firmware/hvmloader/ovmf.c
index 28dd7bc..ea11564 100644
--- a/tools/firmware/hvmloader/ovmf.c
+++ b/tools/firmware/hvmloader/ovmf.c
@@ -123,7 +123,11 @@ static void ovmf_acpi_build_tables(void)
         .dsdt_anycpu = dsdt_anycpu,
         .dsdt_anycpu_len = dsdt_anycpu_len,
         .dsdt_15cpu = NULL, 
-        .dsdt_15cpu_len = 0
+        .dsdt_15cpu_len = 0,
+        .aml_ej0_name = NULL,
+        .aml_adr_dword = NULL,
+        .aml_ej0_name_len = 0,
+        .aml_adr_dword_len = 0,
     };
 
     acpi_build_tables(&config, ACPI_PHYSICAL_ADDRESS);
diff --git a/tools/firmware/hvmloader/rombios.c 
b/tools/firmware/hvmloader/rombios.c
index 810bd24..803c9fa 100644
--- a/tools/firmware/hvmloader/rombios.c
+++ b/tools/firmware/hvmloader/rombios.c
@@ -179,6 +179,10 @@ static void rombios_acpi_build_tables(void)
         .dsdt_anycpu_len = dsdt_anycpu_len,
         .dsdt_15cpu = dsdt_15cpu,
         .dsdt_15cpu_len = dsdt_15cpu_len,
+        .aml_ej0_name = NULL,
+        .aml_adr_dword = NULL,
+        .aml_ej0_name_len = 0,
+        .aml_adr_dword_len = 0,
     };
 
     acpi_build_tables(&config, ACPI_PHYSICAL_ADDRESS);
diff --git a/tools/firmware/hvmloader/seabios.c 
b/tools/firmware/hvmloader/seabios.c
index dd7dfbe..ca01d27 100644
--- a/tools/firmware/hvmloader/seabios.c
+++ b/tools/firmware/hvmloader/seabios.c
@@ -33,6 +33,10 @@
 
 extern unsigned char dsdt_anycpu_qemu_xen[];
 extern int dsdt_anycpu_qemu_xen_len;
+extern unsigned short dsdt_anycpu_qemu_xen_aml_ej0_name[];
+extern unsigned short dsdt_anycpu_qemu_xen_aml_adr_dword[];
+extern int dsdt_anycpu_qemu_xen_aml_ej0_name_len;
+extern int dsdt_anycpu_qemu_xen_aml_adr_dword_len;
 
 struct seabios_info {
     char signature[14]; /* XenHVMSeaBIOS\0 */
@@ -99,6 +103,10 @@ static void seabios_acpi_build_tables(void)
         .dsdt_anycpu_len = dsdt_anycpu_qemu_xen_len,
         .dsdt_15cpu = NULL,
         .dsdt_15cpu_len = 0,
+        .aml_ej0_name = dsdt_anycpu_qemu_xen_aml_ej0_name,
+        .aml_adr_dword = dsdt_anycpu_qemu_xen_aml_adr_dword,
+        .aml_ej0_name_len = dsdt_anycpu_qemu_xen_aml_ej0_name_len,
+        .aml_adr_dword_len = dsdt_anycpu_qemu_xen_aml_adr_dword_len,
     };
 
     acpi_build_tables(&config, rsdp);
diff --git a/tools/firmware/hvmloader/tools/acpi_extract.py 
b/tools/firmware/hvmloader/tools/acpi_extract.py
new file mode 100644
index 0000000..ccec089
--- /dev/null
+++ b/tools/firmware/hvmloader/tools/acpi_extract.py
@@ -0,0 +1,308 @@
+#!/usr/bin/python
+# Copyright (C) 2011 Red Hat, Inc., Michael S. Tsirkin <address@hidden>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+# Process mixed ASL/AML listing (.lst file) produced by iasl -l
+# Locate and execute ACPI_EXTRACT directives, output offset info
+#
+# Documentation of ACPI_EXTRACT_* directive tags:
+#
+# These directive tags output offset information from AML for BIOS runtime
+# table generation.
+# Each directive is of the form:
+# ACPI_EXTRACT_<TYPE> <array_name> <Operator> (...)
+# and causes the extractor to create an array
+# named <array_name> with offset, in the generated AML,
+# of an object of a given type in the following <Operator>.
+#
+# A directive must fit on a single code line.
+#
+# Object type in AML is verified, a mismatch causes a build failure.
+#
+# Directives and operators currently supported are:
+# ACPI_EXTRACT_NAME_DWORD_CONST - extract a Dword Const object from Name()
+# ACPI_EXTRACT_NAME_WORD_CONST - extract a Word Const object from Name()
+# ACPI_EXTRACT_NAME_BYTE_CONST - extract a Byte Const object from Name()
+# ACPI_EXTRACT_METHOD_STRING - extract a NameString from Method()
+# ACPI_EXTRACT_NAME_STRING - extract a NameString from Name()
+# ACPI_EXTRACT_PROCESSOR_START - start of Processor() block
+# ACPI_EXTRACT_PROCESSOR_STRING - extract a NameString from Processor()
+# ACPI_EXTRACT_PROCESSOR_END - offset at last byte of Processor() + 1
+# ACPI_EXTRACT_PKG_START - start of Package block
+#
+# ACPI_EXTRACT_ALL_CODE - create an array storing the generated AML bytecode
+#
+# ACPI_EXTRACT is not allowed anywhere else in code, except in comments.
+
+import re;
+import sys;
+import fileinput;
+
+aml = []
+asl = []
+output = {}
+debug = ""
+
+class asl_line:
+    line = None
+    lineno = None
+    aml_offset = None
+
+def die(diag):
+    sys.stderr.write("Error: %s; %s\n" % (diag, debug))
+    sys.exit(1)
+
+#Store an ASL command, matching AML offset, and input line (for debugging)
+def add_asl(lineno, line):
+    l = asl_line()
+    l.line = line
+    l.lineno = lineno
+    l.aml_offset = len(aml)
+    asl.append(l)
+
+#Store an AML byte sequence
+#Verify that offset output by iasl matches # of bytes so far
+def add_aml(offset, line):
+    o = int(offset, 16);
+    # Sanity check: offset must match size of code so far
+    if (o != len(aml)):
+        die("Offset 0x%x != 0x%x" % (o, len(aml)))
+    # Strip any trailing dots and ASCII dump after "
+    line = re.sub(r'\s*\.*\s*".*$',"", line)
+    # Strip traling whitespace
+    line = re.sub(r'\s+$',"", line)
+    # Strip leading whitespace
+    line = re.sub(r'^\s+',"", line)
+    # Split on whitespace
+    code = re.split(r'\s+', line)
+    for c in code:
+        # Require a legal hex number, two digits
+        if (not(re.search(r'^[0-9A-Fa-f][0-9A-Fa-f]$', c))):
+            die("Unexpected octet %s" % c);
+        aml.append(int(c, 16));
+
+# Process aml bytecode array, decoding AML
+def aml_pkglen_bytes(offset):
+    # PkgLength can be multibyte. Bits 8-7 give the # of extra bytes.
+    pkglenbytes = aml[offset] >> 6;
+    return pkglenbytes + 1
+
+def aml_pkglen(offset):
+    pkgstart = offset
+    pkglenbytes = aml_pkglen_bytes(offset)
+    pkglen = aml[offset] & 0x3F
+    # If multibyte, first nibble only uses bits 0-3
+    if ((pkglenbytes > 0) and (pkglen & 0x30)):
+        die("PkgLen bytes 0x%x but first nibble 0x%x expected 0x0X" %
+            (pkglen, pkglen))
+    offset += 1
+    pkglenbytes -= 1
+    for i in range(pkglenbytes):
+        pkglen |= aml[offset + i] << (i * 8 + 4)
+    if (len(aml) < pkgstart + pkglen):
+        die("PckgLen 0x%x at offset 0x%x exceeds AML size 0x%x" %
+            (pkglen, offset, len(aml)))
+    return pkglen
+
+# Given method offset, find its NameString offset
+def aml_method_string(offset):
+    #0x14 MethodOp PkgLength NameString MethodFlags TermList
+    if (aml[offset] != 0x14):
+        die( "Method offset 0x%x: expected 0x14 actual 0x%x" %
+             (offset, aml[offset]));
+    offset += 1;
+    pkglenbytes = aml_pkglen_bytes(offset)
+    offset += pkglenbytes;
+    return offset;
+
+# Given name offset, find its NameString offset
+def aml_name_string(offset):
+    #0x08 NameOp NameString DataRef
+    if (aml[offset] != 0x08):
+        die( "Name offset 0x%x: expected 0x08 actual 0x%x" %
+             (offset, aml[offset]));
+    offset += 1
+    # Block Name Modifier. Skip it.
+    if (aml[offset] == 0x5c or aml[offset] == 0x5e):
+        offset += 1
+    return offset;
+
+# Given data offset, find dword const offset
+def aml_data_dword_const(offset):
+    #0x08 NameOp NameString DataRef
+    if (aml[offset] != 0x0C):
+        die( "Name offset 0x%x: expected 0x0C actual 0x%x" %
+             (offset, aml[offset]));
+    return offset + 1;
+
+# Given data offset, find word const offset
+def aml_data_word_const(offset):
+    #0x08 NameOp NameString DataRef
+    if (aml[offset] != 0x0B):
+        die( "Name offset 0x%x: expected 0x0B actual 0x%x" %
+             (offset, aml[offset]));
+    return offset + 1;
+
+# Given data offset, find byte const offset
+def aml_data_byte_const(offset):
+    #0x08 NameOp NameString DataRef
+    if (aml[offset] != 0x0A):
+        die( "Name offset 0x%x: expected 0x0A actual 0x%x" %
+             (offset, aml[offset]));
+    return offset + 1;
+
+# Given name offset, find dword const offset
+def aml_name_dword_const(offset):
+    return aml_data_dword_const(aml_name_string(offset) + 4)
+
+# Given name offset, find word const offset
+def aml_name_word_const(offset):
+    return aml_data_word_const(aml_name_string(offset) + 4)
+
+# Given name offset, find byte const offset
+def aml_name_byte_const(offset):
+    return aml_data_byte_const(aml_name_string(offset) + 4)
+
+def aml_processor_start(offset):
+    #0x5B 0x83 ProcessorOp PkgLength NameString ProcID
+    if ((aml[offset] != 0x5B) or (aml[offset + 1] != 0x83)):
+        die( "Name offset 0x%x: expected 0x5B 0x83 actual 0x%x 0x%x" %
+             (offset, aml[offset], aml[offset + 1]));
+    return offset
+
+def aml_processor_string(offset):
+    #0x5B 0x83 ProcessorOp PkgLength NameString ProcID
+    start = aml_processor_start(offset)
+    offset += 2
+    pkglenbytes = aml_pkglen_bytes(offset)
+    offset += pkglenbytes
+    return offset
+
+def aml_processor_end(offset):
+    start = aml_processor_start(offset)
+    offset += 2
+    pkglenbytes = aml_pkglen_bytes(offset)
+    pkglen = aml_pkglen(offset)
+    return offset + pkglen
+
+def aml_package_start(offset):
+    offset = aml_name_string(offset) + 4
+    # 0x12 PkgLength NumElements PackageElementList
+    if (aml[offset] != 0x12):
+        die( "Name offset 0x%x: expected 0x12 actual 0x%x" %
+             (offset, aml[offset]));
+    offset += 1
+    return offset + aml_pkglen_bytes(offset) + 1
+
+lineno = 0
+for line in fileinput.input():
+    # Strip trailing newline
+    line = line.rstrip();
+    # line number and debug string to output in case of errors
+    lineno = lineno + 1
+    debug = "input line %d: %s" % (lineno, line)
+    #ASL listing: space, then line#, then ...., then code
+    pasl = re.compile('^\s+([0-9]+)\.\.\.\.\s*')
+    m = pasl.search(line)
+    if (m):
+        add_asl(lineno, pasl.sub("", line));
+    # AML listing: offset in hex, then ...., then code
+    paml = re.compile('^([0-9A-Fa-f]+)\.\.\.\.\s*')
+    m = paml.search(line)
+    if (m):
+        add_aml(m.group(1), paml.sub("", line))
+
+# Now go over code
+# Track AML offset of a previous non-empty ASL command
+prev_aml_offset = -1
+for i in range(len(asl)):
+    debug = "input line %d: %s" % (asl[i].lineno, asl[i].line)
+
+    l = asl[i].line
+
+    # skip if not an extract directive
+    a = len(re.findall(r'ACPI_EXTRACT', l))
+    if (not a):
+        # If not empty, store AML offset. Will be used for sanity checks
+        # IASL seems to put {}. at random places in the listing.
+        # Ignore any non-words for the purpose of this test.
+        m = re.search(r'\w+', l)
+        if (m):
+                prev_aml_offset = asl[i].aml_offset
+        continue
+
+    if (a > 1):
+        die("Expected at most one ACPI_EXTRACT per line, actual %d" % a)
+
+    mext = re.search(r'''
+                      ^\s* # leading whitespace
+                      /\*\s* # start C comment
+                      (ACPI_EXTRACT_\w+) # directive: group(1)
+                      \s+ # whitspace separates directive from array name
+                      (\w+) # array name: group(2)
+                      \s*\*/ # end of C comment
+                      \s*$ # trailing whitespace
+                      ''', l, re.VERBOSE)
+    if (not mext):
+        die("Stray ACPI_EXTRACT in input")
+
+    # previous command must have produced some AML,
+    # otherwise we are in a middle of a block
+    if (prev_aml_offset == asl[i].aml_offset):
+        die("ACPI_EXTRACT directive in the middle of a block")
+
+    directive = mext.group(1)
+    array = mext.group(2)
+    offset = asl[i].aml_offset
+
+    if (directive == "ACPI_EXTRACT_ALL_CODE"):
+        if array in output:
+            die("%s directive used more than once" % directive)
+        output[array] = aml
+        continue
+    if (directive == "ACPI_EXTRACT_NAME_DWORD_CONST"):
+        offset = aml_name_dword_const(offset)
+    elif (directive == "ACPI_EXTRACT_NAME_WORD_CONST"):
+        offset = aml_name_word_const(offset)
+    elif (directive == "ACPI_EXTRACT_NAME_BYTE_CONST"):
+        offset = aml_name_byte_const(offset)
+    elif (directive == "ACPI_EXTRACT_NAME_STRING"):
+        offset = aml_name_string(offset)
+    elif (directive == "ACPI_EXTRACT_METHOD_STRING"):
+        offset = aml_method_string(offset)
+    elif (directive == "ACPI_EXTRACT_PROCESSOR_START"):
+        offset = aml_processor_start(offset)
+    elif (directive == "ACPI_EXTRACT_PROCESSOR_STRING"):
+        offset = aml_processor_string(offset)
+    elif (directive == "ACPI_EXTRACT_PROCESSOR_END"):
+        offset = aml_processor_end(offset)
+    elif (directive == "ACPI_EXTRACT_PKG_START"):
+        offset = aml_package_start(offset)
+    else:
+        die("Unsupported directive %s" % directive)
+
+    if array not in output:
+        output[array] = []
+    output[array].append(offset)
+
+debug = "at end of file"
+
+def get_value_type(maxvalue):
+    #Use type large enough to fit the table
+    if (maxvalue >= 0x10000):
+            return "int"
+    elif (maxvalue >= 0x100):
+            return "short"
+    else:
+            return "char"
+
+# Pretty print output
+for array in output.keys():
+    otype = get_value_type(max(output[array]))
+    odata = []
+    for value in output[array]:
+        odata.append("0x%x" % value)
+    sys.stdout.write("unsigned %s %s[] = {\n" % (otype, array))
+    sys.stdout.write(",\n".join(odata))
+    sys.stdout.write('\n};\n');
diff --git a/tools/firmware/hvmloader/tools/acpi_extract_preprocess.py 
b/tools/firmware/hvmloader/tools/acpi_extract_preprocess.py
new file mode 100644
index 0000000..4ae364e
--- /dev/null
+++ b/tools/firmware/hvmloader/tools/acpi_extract_preprocess.py
@@ -0,0 +1,41 @@
+#!/usr/bin/python
+# Copyright (C) 2011 Red Hat, Inc., Michael S. Tsirkin <address@hidden>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+# Read a preprocessed ASL listing and put each ACPI_EXTRACT
+# directive in a comment, to make iasl skip it.
+# We also put each directive on a new line, the machinery
+# in tools/acpi_extract.py requires this.
+
+import re;
+import sys;
+import fileinput;
+
+def die(diag):
+    sys.stderr.write("Error: %s\n" % (diag))
+    sys.exit(1)
+
+# Note: () around pattern make split return matched string as part of list
+psplit = re.compile(r''' (
+                          \b # At word boundary
+                          ACPI_EXTRACT_\w+ # directive
+                          \s+ # some whitespace
+                          \w+ # array name
+                         )''', re.VERBOSE);
+
+lineno = 0
+for line in fileinput.input():
+    # line number and debug string to output in case of errors
+    lineno = lineno + 1
+    debug = "input line %d: %s" % (lineno, line.rstrip())
+
+    s = psplit.split(line);
+    # The way split works, each odd item is the matching ACPI_EXTRACT 
directive.
+    # Put each in a comment, and on a line by itself.
+    for i in range(len(s)):
+        if (i % 2):
+            sys.stdout.write("\n/* %s */\n" % s[i])
+        else:
+            sys.stdout.write(s[i])
+
-- 
1.8.3.4