[Qemu-devel] [PATCH FYI 13/13] hw/i386: generate AML for the VMGENID device (WIP)

[Laszlo Ersek <lersek@redhat.com>]

This patch implements the "ACPI device, control methods" section of
"docs/vmgenid.txt", with dynamic AML generation.

A small portion of this patch was inspired by Gal Hammer's

  [PATCH V15 4/5] i386: add a Virtual Machine Generation ID device
  http://thread.gmane.org/gmane.comp.emulators.qemu/332451/focus=332454

TODO: the ACPICA instance that is built into the Linux kernel warns about
the fact that both _L04 and _E04 are provided by GPE 04, when the code in
this patch is active. Therefore this patch should also conditionalize _L04
(ATM in "hw/i386/acpi-dsdt.dsl" and "hw/i386/q35-acpi-dsdt.dsl"), so that
they are only generated when VMGENID is *not* active.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gal Hammer <ghammer@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/i386/acpi-build.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index a742f25..67be94a 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1126,6 +1126,85 @@ build_ssdt(GArray *table_data, GArray *linker,
         aml_append(ssdt, scope);
     }
 
+    if (true /* lersek: misc->vmgenid_iobase */) {
+        unsigned adbp_offset;
+        size_t genid_incr;
+
+        scope = aml_scope("\\_SB");
+        dev = aml_device("VMGI");
+
+        aml_append(dev, aml_name_decl("_CID", aml_string("VM_Gen_Counter")));
+        aml_append(dev, aml_name_decl("_DDN", aml_string("VM_Gen_Counter")));
+        aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0002")));
+
+        aml_append(dev, aml_name_decl("_STA", aml_int(0xF)));
+
+        method = aml_method_serialized("ADDR", 0, true);
+
+        aml_append(method,
+                   aml_data_table_region("TBLR",
+                                         aml_string("UEFI"),
+                                         aml_string("%s", ACPI_BUILD_APPNAME6),
+                                         aml_string("QEMUPARM")));
+        field = aml_field("TBLR", AML_ANY_ACC, AML_PRESERVE);
+        adbp_offset = offsetof (AcpiQemuParamTable, vmgenid_addr_base_ptr);
+        /* Offset() before ADBP, expressed in bits */
+        aml_append(field, aml_reserved_field(adbp_offset * 8));
+        aml_append(field, aml_named_field("ADBP", 64));
+        aml_append(method, field);
+
+        aml_append(method,
+                   aml_operation_region("VMGR", AML_SYSTEM_IO,
+                                        0x512 /* lersek: misc->vmgenid_iobase */,
+                                        9));
+        field = aml_field("VMGR", AML_DWORD_ACC, AML_PRESERVE);
+        aml_append(field, aml_named_field("PTLO", 32));
+        aml_append(field, aml_named_field("PTHI", 32));
+        aml_append(field, aml_access_field(AML_BYTE_ACC));
+        aml_append(field, aml_named_field("DONE", 8));
+        aml_append(method, field);
+
+        aml_append(method, aml_name_decl("RESU", aml_buffer(8, NULL)));
+        aml_append(method,
+                  aml_create_qword_field(aml_name("RESU"), aml_int(0),
+                                         "ADFU"));
+        aml_append(method,
+                  aml_create_dword_field(aml_name("RESU"), aml_int(0),
+                                         "ADLO"));
+        aml_append(method,
+                  aml_create_dword_field(aml_name("RESU"), aml_int(4),
+                                         "ADHI"));
+
+        /*
+         * Offset increment from the end of the parameter table (ie. where ADBP
+         * points to) until the generation ID field, skipping over the "OVMF
+         * SDT Header probe suppressor" and "VMGenID alignment padding" fields
+         * in the blob.
+         */
+        genid_incr = VM_GENERATION_ID_OFFSET - sizeof(AcpiQemuParamTable);
+        aml_append(method, aml_store(aml_add(aml_name("ADBP"),
+                                             aml_int(genid_incr)),
+                                     aml_name("ADFU")));
+        aml_append(method, aml_store(aml_name("ADLO"), aml_name("PTLO")));
+        aml_append(method, aml_store(aml_name("ADHI"), aml_name("PTHI")));
+        aml_append(method, aml_store(aml_int(0), aml_name("DONE")));
+
+        pkg = aml_package(2);
+        aml_append(pkg, aml_name("ADLO"));
+        aml_append(pkg, aml_name("ADHI"));
+        aml_append(method, aml_return(pkg));
+
+        aml_append(dev, method);
+        aml_append(scope, dev);
+        aml_append(ssdt, scope);
+
+        scope = aml_scope("\\_GPE");
+        method = aml_method("_E04", 0);
+        aml_append(method, aml_notify(aml_name("\\_SB.VMGI"), aml_int(0x80)));
+        aml_append(scope, method);
+        aml_append(ssdt, scope);
+    }
+
     sb_scope = aml_scope("\\_SB");
     {
         /* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
-- 
1.8.3.1