[PATCH v7] isa-applesmc: provide OSK forwarding on Apple hosts

[Vladislav Yaroshchuk]

On Apple hosts we can read AppleSMC OSK key directly from host's
SMC and forward this value to QEMU Guest.

New 'hostosk' property is added:
  `-device isa-applesmc,hostosk=on`
The property is set to 'on' by default for machine version > 6.2

Apple licence allows use and run up to two additional copies
or instances of macOS operating system within virtual operating system
environments on each Apple-branded computer that is already running
the Apple Software, for purposes of:
  * software development
  * testing during software development
  * using macOS Server
  * personal, non-commercial use

Guest macOS requires AppleSMC with correct OSK. The most legal
way to pass it to the Guest is to forward the key from host SMC
without any value exposion.

Based on 
https://web.archive.org/web/20200103161737/osxbook.com/book/bonus/chapter7/tpmdrmmyth/

Signed-off-by: Vladislav Yaroshchuk <yaroshchuk2000@gmail.com>
---
 hw/arm/virt.c              |   1 +
 hw/core/machine.c          |   5 ++
 hw/i386/pc_piix.c          |   1 +
 hw/i386/pc_q35.c           |   1 +
 hw/m68k/virt.c             |   1 +
 hw/misc/applesmc.c         | 123 ++++++++++++++++++++++++++++++++++++-
 hw/ppc/spapr.c             |   1 +
 hw/s390x/s390-virtio-ccw.c |   1 +
 include/hw/boards.h        |   3 +
 9 files changed, 135 insertions(+), 2 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 6bce595aba..4d6b72fe6f 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2858,6 +2858,7 @@ type_init(machvirt_machine_init);
 
 static void virt_machine_6_2_options(MachineClass *mc)
 {
+    compat_props_add(mc->compat_props, hw_compat_6_2, hw_compat_6_2_len);
 }
 DEFINE_VIRT_MACHINE_AS_LATEST(6, 2)
 
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 53a99abc56..afa871378e 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -37,6 +37,11 @@
 #include "hw/virtio/virtio.h"
 #include "hw/virtio/virtio-pci.h"
 
+GlobalProperty hw_compat_6_2[] = {
+    { "isa-applesmc", "hostosk", "off" }
+};
+const size_t hw_compat_6_2_len = G_N_ELEMENTS(hw_compat_6_2);
+
 GlobalProperty hw_compat_6_1[] = {
     { "vhost-user-vsock-device", "seqpacket", "off" },
     { "nvme-ns", "shared", "off" },
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 223dd3e05d..1c2ab5222e 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -420,6 +420,7 @@ static void pc_i440fx_6_2_machine_options(MachineClass *m)
     m->alias = "pc";
     m->is_default = true;
     pcmc->default_cpu_version = 1;
+    compat_props_add(m->compat_props, hw_compat_6_2, hw_compat_6_2_len);
 }
 
 DEFINE_I440FX_MACHINE(v6_2, "pc-i440fx-6.2", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index e1e100316d..7186d736d3 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -366,6 +366,7 @@ static void pc_q35_6_2_machine_options(MachineClass *m)
     pc_q35_machine_options(m);
     m->alias = "q35";
     pcmc->default_cpu_version = 1;
+    compat_props_add(m->compat_props, hw_compat_6_2, hw_compat_6_2_len);
 }
 
 DEFINE_Q35_MACHINE(v6_2, "pc-q35-6.2", NULL,
diff --git a/hw/m68k/virt.c b/hw/m68k/virt.c
index 0efa4a45c7..10281a81c5 100644
--- a/hw/m68k/virt.c
+++ b/hw/m68k/virt.c
@@ -306,6 +306,7 @@ type_init(virt_machine_register_types)
 
 static void virt_machine_6_2_options(MachineClass *mc)
 {
+    compat_props_add(mc->compat_props, hw_compat_6_2, hw_compat_6_2_len);
 }
 DEFINE_VIRT_MACHINE(6, 2, true)
 
diff --git a/hw/misc/applesmc.c b/hw/misc/applesmc.c
index 1b9acaf1d3..72755db380 100644
--- a/hw/misc/applesmc.c
+++ b/hw/misc/applesmc.c
@@ -37,6 +37,11 @@
 #include "qemu/module.h"
 #include "qemu/timer.h"
 #include "qom/object.h"
+#include "qapi/error.h"
+
+#if defined(__APPLE__) && defined(__MACH__)
+#include <IOKit/IOKitLib.h>
+#endif
 
 /* #define DEBUG_SMC */
 
@@ -109,6 +114,7 @@ struct AppleSMCState {
     uint8_t data_pos;
     uint8_t data[255];
     char *osk;
+    bool hostosk;
     QLIST_HEAD(, AppleSMCData) data_def;
 };
 
@@ -312,6 +318,101 @@ static const MemoryRegionOps applesmc_err_io_ops = {
     },
 };
 
+#if defined(__APPLE__) && defined(__MACH__)
+/*
+ * Based on
+ * 
https://web.archive.org/web/20200103161737/osxbook.com/book/bonus/chapter7/tpmdrmmyth/
+ */
+enum {
+    SMC_HANDLE_EVENT     = 2,
+    SMC_READ_KEY         = 5
+};
+
+struct AppleSMCParam {
+    uint32_t key;
+    uint8_t pad0[22];
+    IOByteCount data_size;
+    uint8_t pad1[10];
+    uint8_t command;
+    uint32_t pad2;
+    uint8_t bytes[32];
+};
+
+static bool applesmc_read_host_osk(char *host_osk, Error **errp)
+{
+    assert(host_osk != NULL);
+
+    io_service_t hostsmc_service = IO_OBJECT_NULL;
+    io_connect_t hostsmc_connect = IO_OBJECT_NULL;
+    size_t smc_param_size = sizeof(struct AppleSMCParam);
+    IOReturn status = kIOReturnError;
+    int i;
+
+    struct AppleSMCParam smc_param[2] = {
+         {
+             .key = ('OSK0'),
+             .data_size = sizeof(smc_param[0].bytes),
+             .command = SMC_READ_KEY,
+         }, {
+             .key = ('OSK1'),
+             .data_size = sizeof(smc_param[0].bytes),
+             .command = SMC_READ_KEY,
+         },
+    };
+
+    hostsmc_service = IOServiceGetMatchingService(
+        kIOMasterPortDefault,
+        IOServiceMatching("AppleSMC"));
+    if (hostsmc_service == IO_OBJECT_NULL) {
+        error_setg(errp, "Unable to get host-AppleSMC service");
+        goto error;
+    }
+
+    status = IOServiceOpen(hostsmc_service,
+                           mach_task_self(),
+                           0,
+                           &hostsmc_connect);
+    if (status != kIOReturnSuccess || hostsmc_connect == IO_OBJECT_NULL) {
+        error_setg(errp, "Unable to open host-AppleSMC service");
+        goto error;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(smc_param); ++i) {
+        status = IOConnectCallStructMethod(
+                hostsmc_connect,
+                SMC_HANDLE_EVENT,
+                &smc_param[i],
+                sizeof(struct AppleSMCParam),
+                &smc_param[i],
+                &smc_param_size
+            );
+
+        if (status != kIOReturnSuccess) {
+            error_setg(errp, "Unable to read OSK from host-AppleSMC");
+            goto error;
+        }
+    }
+
+    memcpy(host_osk, smc_param[0].bytes, 32);
+    memcpy(host_osk + 32, smc_param[1].bytes, 32);
+
+    IOServiceClose(hostsmc_connect);
+    IOObjectRelease(hostsmc_service);
+    return true;
+
+error:
+    IOServiceClose(hostsmc_connect);
+    IOObjectRelease(hostsmc_service);
+    return false;
+}
+#else
+static bool applesmc_read_host_osk(char *host_osk, Error **errp)
+{
+    error_setg(errp, "OSK read is not supported on this host");
+    return false;
+}
+#endif
+
 static void applesmc_isa_realize(DeviceState *dev, Error **errp)
 {
     AppleSMCState *s = APPLE_SMC(dev);
@@ -331,9 +432,26 @@ static void applesmc_isa_realize(DeviceState *dev, Error 
**errp)
     isa_register_ioport(&s->parent_obj, &s->io_err,
                         s->iobase + APPLESMC_ERR_PORT);
 
-    if (!s->osk || (strlen(s->osk) != 64)) {
-        warn_report("Using AppleSMC with invalid key");
+    if (s->osk && s->hostosk) {
+        error_setg(errp, "-osk property cannot be used with -hostosk=on");
+    }
+
+    if (!s->osk && !s->hostosk) {
         s->osk = default_osk;
+        warn_report("Using AppleSMC with default (dummy) OSK");
+    }
+
+    if (s->hostosk) {
+        s->osk = g_malloc0(65);
+        /* Fail hard if we cannot read requested host OSK */
+        if (!applesmc_read_host_osk(s->osk, errp)) {
+            g_assert_not_reached();
+        }
+    }
+
+    if (s->osk && strlen(s->osk) != 64) {
+        /* Only valid OSK is accepted within 'osk' property */
+        error_setg(errp, "Using AppleSMC with key of invalid length");
     }
 
     QLIST_INIT(&s->data_def);
@@ -344,6 +462,7 @@ static Property applesmc_isa_properties[] = {
     DEFINE_PROP_UINT32(APPLESMC_PROP_IO_BASE, AppleSMCState, iobase,
                        APPLESMC_DEFAULT_IOBASE),
     DEFINE_PROP_STRING("osk", AppleSMCState, osk),
+    DEFINE_PROP_BOOL("hostosk", AppleSMCState, hostosk, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 3b5fd749be..fefac898e6 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4671,6 +4671,7 @@ static void 
spapr_machine_latest_class_options(MachineClass *mc)
 static void spapr_machine_6_2_class_options(MachineClass *mc)
 {
     /* Defaults for the latest behaviour inherited from the base class */
+    compat_props_add(mc->compat_props, hw_compat_6_2, hw_compat_6_2_len);
 }
 
 DEFINE_SPAPR_MACHINE(6_2, "6.2", true);
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 653587ea62..3abb249c3d 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -797,6 +797,7 @@ static void ccw_machine_6_2_instance_options(MachineState 
*machine)
 
 static void ccw_machine_6_2_class_options(MachineClass *mc)
 {
+    compat_props_add(mc->compat_props, hw_compat_6_2, hw_compat_6_2_len);
 }
 DEFINE_CCW_MACHINE(6_2, "6.2", true);
 
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 9c1c190104..b7b68471ff 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -375,6 +375,9 @@ struct MachineState {
     } \
     type_init(machine_initfn##_register_types)
 
+extern GlobalProperty hw_compat_6_2[];
+extern const size_t hw_compat_6_2_len;
+
 extern GlobalProperty hw_compat_6_1[];
 extern const size_t hw_compat_6_1_len;
 
-- 
2.23.0