1 files changed, 54 insertions, 0 deletions
diff --git a/hw/acpi/pci-bridge.c b/hw/acpi/pci-bridge.c
index 7baa7034a1..394a919479 100644
--- a/hw/acpi/pci-bridge.c
+++ b/hw/acpi/pci-bridge.c
@@ -35,3 +35,57 @@ void build_pci_bridge_aml(AcpiDevAmlIf *adev, Aml *scope)
         }
     }
 }
+
+Aml *build_pci_bridge_edsm(void)
+{
+    Aml *method, *ifctx;
+    Aml *zero = aml_int(0);
+    Aml *func = aml_arg(2);
+    Aml *ret = aml_local(0);
+    Aml *aidx = aml_local(1);
+    Aml *params = aml_arg(4);
+
+    method = aml_method("EDSM", 5, AML_SERIALIZED);
+
+    /* get supported functions */
+    ifctx = aml_if(aml_equal(func, zero));
+    {
+        /* 1: have supported functions */
+        /* 7: support for function 7 */
+        const uint8_t caps = 1 | BIT(7);
+        build_append_pci_dsm_func0_common(ifctx, ret);
+        aml_append(ifctx, aml_store(aml_int(caps), aml_index(ret, zero)));
+        aml_append(ifctx, aml_return(ret));
+    }
+    aml_append(method, ifctx);
+
+    /* handle specific functions requests */
+    /*
+     * PCI Firmware Specification 3.1
+     * 4.6.7. _DSM for Naming a PCI or PCI Express Device Under
+     *        Operating Systems
+     */
+    ifctx = aml_if(aml_equal(func, aml_int(7)));
+    {
+       Aml *pkg = aml_package(2);
+       aml_append(pkg, zero);
+       /* optional, if not impl. should return null string */
+       aml_append(pkg, aml_string("%s", ""));
+       aml_append(ifctx, aml_store(pkg, ret));
+
+       /*
+        * IASL is fine when initializing Package with computational data,
+        * however it makes guest unhappy /it fails to process such AML/.
+        * So use runtime assignment to set acpi-index after initializer
+        * to make OSPM happy.
+        */
+       aml_append(ifctx,
+           aml_store(aml_derefof(aml_index(params, aml_int(0))), aidx));
+       aml_append(ifctx, aml_store(aidx, aml_index(ret, zero)));
+       aml_append(ifctx, aml_return(ret));
+    }
+    aml_append(method, ifctx);
+
+    return method;
+}
+