hw/misc: applesmc: use host osk as default on macs

When running on a Mac, QEMU is able to get the host OSK and use it as
the default value for the AppleSMC device. The OSK query operation
doesn't require administrator privileges and can be executed by any user
on the system. This patch is based on open-source code from Apple, just
like the implementation from VirtualBox.

Apple:
https://opensource.apple.com/source/IOKitUser/IOKitUser-647.6.13/pwr_mgt.subproj/IOPMLibPrivate.c
https://opensource.apple.com/source/PowerManagement/PowerManagement-637.60.1/pmconfigd/PrivateLib.c

VirtualBox:
https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Devices/EFI/DevSmc.cpp#L516

Signed-off-by: Pedro Tôrres <t0rr3sp3dr0@gmail.com>

1 files changed, 191 insertions, 1 deletions

diff --git a/hw/misc/applesmc.c b/hw/misc/applesmc.c
index 1b9acaf..cec247b 100644
--- a/hw/misc/applesmc.c
+++ b/hw/misc/applesmc.c
@@ -38,6 +38,171 @@
 #include "qemu/timer.h"
 #include "qom/object.h"
 
+#if defined(__APPLE__) && defined(__MACH__)
+#include <IOKit/IOKitLib.h>
+
+enum {
+    kSMCSuccess     = 0x00,
+    kSMCKeyNotFound = 0x84
+};
+
+enum {
+    kSMCUserClientOpen  = 0x00,
+    kSMCUserClientClose = 0x01,
+    kSMCHandleYPCEvent  = 0x02,
+    kSMCReadKey         = 0x05,
+    kSMCGetKeyInfo      = 0x09
+};
+
+typedef struct SMCVersion {
+    uint8_t  major;
+    uint8_t  minor;
+    uint8_t  build;
+    uint8_t  reserved;
+    uint16_t release;
+} SMCVersion;
+
+typedef struct SMCPLimitData {
+    uint16_t version;
+    uint16_t length;
+    uint32_t cpuPLimit;
+    uint32_t gpuPLimit;
+    uint32_t memPLimit;
+} SMCPLimitData;
+
+typedef struct SMCKeyInfoData {
+    IOByteCount dataSize;
+    uint32_t    dataType;
+    uint8_t     dataAttributes;
+} SMCKeyInfoData;
+
+typedef struct {
+    uint32_t       key;
+    SMCVersion     vers;
+    SMCPLimitData  pLimitData;
+    SMCKeyInfoData keyInfo;
+    uint8_t        result;
+    uint8_t        status;
+    uint8_t        data8;
+    uint32_t       data32;
+    uint8_t        bytes[32];
+} SMCParamStruct;
+
+static IOReturn smc_call_struct_method(uint32_t selector,
+                                       SMCParamStruct *inputStruct,
+                                       SMCParamStruct *outputStruct)
+{
+    IOReturn ret;
+
+    size_t inputStructCnt = sizeof(SMCParamStruct);
+    size_t outputStructCnt = sizeof(SMCParamStruct);
+
+    io_service_t smcService = IO_OBJECT_NULL;
+    io_connect_t smcConnect = IO_OBJECT_NULL;
+
+    smcService = IOServiceGetMatchingService(kIOMasterPortDefault,
+                                             IOServiceMatching("AppleSMC"));
+    if (smcService == IO_OBJECT_NULL) {
+        ret = kIOReturnNotFound;
+        goto exit;
+    }
+
+    ret = IOServiceOpen(smcService, mach_task_self(), 1, &smcConnect);
+    if (ret != kIOReturnSuccess) {
+        smcConnect = IO_OBJECT_NULL;
+        goto exit;
+    }
+    if (smcConnect == IO_OBJECT_NULL) {
+        ret = kIOReturnError;
+        goto exit;
+    }
+
+    ret = IOConnectCallMethod(smcConnect, kSMCUserClientOpen,
+                              NULL, 0, NULL, 0,
+                              NULL, NULL, NULL, NULL);
+    if (ret != kIOReturnSuccess) {
+        goto exit;
+    }
+
+    ret = IOConnectCallStructMethod(smcConnect, selector,
+                                    inputStruct, inputStructCnt,
+                                    outputStruct, &outputStructCnt);
+
+exit:
+    if (smcConnect != IO_OBJECT_NULL) {
+        IOConnectCallMethod(smcConnect, kSMCUserClientClose,
+                            NULL, 0, NULL, 0, NULL,
+                            NULL, NULL, NULL);
+        IOServiceClose(smcConnect);
+    }
+
+    return ret;
+}
+
+static IOReturn smc_read_key(uint32_t key,
+                             uint8_t *bytes,
+                             IOByteCount *dataSize)
+{
+    IOReturn ret;
+
+    SMCParamStruct inputStruct;
+    SMCParamStruct outputStruct;
+
+    if (key == 0 || bytes == NULL) {
+        ret = kIOReturnCannotWire;
+        goto exit;
+    }
+
+    /* determine key's data size */
+    memset(&inputStruct, 0, sizeof(SMCParamStruct));
+    inputStruct.data8 = kSMCGetKeyInfo;
+    inputStruct.key = key;
+
+    memset(&outputStruct, 0, sizeof(SMCParamStruct));
+    ret = smc_call_struct_method(kSMCHandleYPCEvent, &inputStruct, &outputStruct);
+    if (ret != kIOReturnSuccess) {
+        goto exit;
+    }
+    if (outputStruct.result == kSMCKeyNotFound) {
+        ret = kIOReturnNotFound;
+        goto exit;
+    }
+    if (outputStruct.result != kSMCSuccess) {
+        ret = kIOReturnInternalError;
+        goto exit;
+    }
+
+    /* get key value */
+    memset(&inputStruct, 0, sizeof(SMCParamStruct));
+    inputStruct.data8 = kSMCReadKey;
+    inputStruct.key = key;
+    inputStruct.keyInfo.dataSize = outputStruct.keyInfo.dataSize;
+
+    memset(&outputStruct, 0, sizeof(SMCParamStruct));
+    ret = smc_call_struct_method(kSMCHandleYPCEvent, &inputStruct, &outputStruct);
+    if (ret != kIOReturnSuccess) {
+        goto exit;
+    }
+    if (outputStruct.result == kSMCKeyNotFound) {
+        ret = kIOReturnNotFound;
+        goto exit;
+    }
+    if (outputStruct.result != kSMCSuccess) {
+        ret = kIOReturnInternalError;
+        goto exit;
+    }
+
+    memset(bytes, 0, *dataSize);
+    if (*dataSize > inputStruct.keyInfo.dataSize) {
+        *dataSize = inputStruct.keyInfo.dataSize;
+    }
+    memcpy(bytes, outputStruct.bytes, *dataSize);
+
+exit:
+    return ret;
+}
+#endif
+
 /* #define DEBUG_SMC */
 
 #define APPLESMC_DEFAULT_IOBASE        0x300
@@ -315,6 +480,7 @@ static const MemoryRegionOps applesmc_err_io_ops = {
 static void applesmc_isa_realize(DeviceState *dev, Error **errp)
 {
     AppleSMCState *s = APPLE_SMC(dev);
+    bool valid_key = false;
 
     memory_region_init_io(&s->io_data, OBJECT(s), &applesmc_data_io_ops, s,
                           "applesmc-data", 1);
@@ -331,7 +497,31 @@ 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)) {
+    if (s->osk) {
+        valid_key = strlen(s->osk) == 64;
+    } else {
+#if defined(__APPLE__) && defined(__MACH__)
+        IOReturn ret;
+        IOByteCount size = 32;
+
+        ret = smc_read_key('OSK0', (uint8_t *) default_osk, &size);
+        if (ret != kIOReturnSuccess) {
+            goto failure;
+        }
+
+        ret = smc_read_key('OSK1', (uint8_t *) default_osk + size, &size);
+        if (ret != kIOReturnSuccess) {
+            goto failure;
+        }
+
+        warn_report("Using AppleSMC with host key");
+        valid_key = true;
+        s->osk = default_osk;
+failure:;
+#endif
+    }
+
+    if (!valid_key) {
         warn_report("Using AppleSMC with invalid key");
         s->osk = default_osk;
     }