[Qemu-devel] [PATCH 2/2] PPC: Cuda: Use cuda timer to expose tbfreq to guest

[Alexander Graf <agraf@suse.de>]

Mac OS X calibrates a number of frequencies on bootup based on reading
tb values on bootup and comparing them to via cuda timer values.

The only variable we can really steer well (thanks to KVM) is the cuda
frequency. So let's use that one to fake Mac OS X into believing the
bus frequency is tbfreq * 4. That way Mac OS X will automatically
calculate the correct timebase frequency.

With this patch and the patch set I posted earlier I can successfully
run Mac OS X 10.2, 10.3 and 10.4 guests with -M mac99 on TCG and KVM.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 hw/misc/macio/cuda.c  | 28 ++++++++++++++++++++++------
 hw/misc/macio/macio.c | 10 ++++++++++
 hw/ppc/mac.h          |  2 ++
 hw/ppc/mac_newworld.c |  1 +
 hw/ppc/mac_oldworld.c |  1 +
 5 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/hw/misc/macio/cuda.c b/hw/misc/macio/cuda.c
index ff6051d..81e54b8 100644
--- a/hw/misc/macio/cuda.c
+++ b/hw/misc/macio/cuda.c
@@ -102,7 +102,6 @@
 #define CUDA_TIMER_TICKLE		0x24
 #define CUDA_COMBINED_FORMAT_IIC	0x25
 
-#define CUDA_TIMER_FREQ (4700000 / 6)
 #define CUDA_ADB_POLL_FREQ 50
 
 /* CUDA returns time_t's offset from Jan 1, 1904, not 1970 */
@@ -123,13 +122,22 @@ static void cuda_update_irq(CUDAState *s)
     }
 }
 
+static uint64_t get_tb(uint64_t freq)
+{
+    return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
+                    freq, get_ticks_per_sec());
+}
+
 static unsigned int get_counter(CUDATimer *s)
 {
     int64_t d;
     unsigned int counter;
+    uint64_t tb_diff;
+
+    /* Reverse of the tb calculation algorithm that Mac OS X uses on bootup. */
+    tb_diff = get_tb(s->frequency) - s->load_time;
+    d = (tb_diff * 0xBF401675E5DULL) / (s->frequency << 24);
 
-    d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - s->load_time,
-                 CUDA_TIMER_FREQ, get_ticks_per_sec());
     if (s->index == 0) {
         /* the timer goes down from latch to -1 (period of latch + 2) */
         if (d <= (s->counter_value + 1)) {
@@ -147,7 +155,7 @@ static unsigned int get_counter(CUDATimer *s)
 static void set_counter(CUDAState *s, CUDATimer *ti, unsigned int val)
 {
     CUDA_DPRINTF("T%d.counter=%d\n", 1 + (ti->timer == NULL), val);
-    ti->load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+    ti->load_time = get_tb(s->frequency);
     ti->counter_value = val;
     cuda_timer_update(s, ti, ti->load_time);
 }
@@ -159,7 +167,7 @@ static int64_t get_next_irq_time(CUDATimer *s, int64_t current_time)
 
     /* current counter value */
     d = muldiv64(current_time - s->load_time,
-                 CUDA_TIMER_FREQ, get_ticks_per_sec());
+                 s->frequency, get_ticks_per_sec());
     /* the timer goes down from latch to -1 (period of latch + 2) */
     if (d <= (s->counter_value + 1)) {
         counter = (s->counter_value - d) & 0xffff;
@@ -178,7 +186,7 @@ static int64_t get_next_irq_time(CUDATimer *s, int64_t current_time)
     }
     CUDA_DPRINTF("latch=%d counter=%" PRId64 " delta_next=%" PRId64 "\n",
                  s->latch, d, next_time - d);
-    next_time = muldiv64(next_time, get_ticks_per_sec(), CUDA_TIMER_FREQ) +
+    next_time = muldiv64(next_time, get_ticks_per_sec(), s->frequency) +
         s->load_time;
     if (next_time <= current_time)
         next_time = current_time + 1;
@@ -688,6 +696,8 @@ static void cuda_realizefn(DeviceState *dev, Error **errp)
     struct tm tm;
 
     s->timers[0].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, cuda_timer1, s);
+    s->timers[0].frequency = s->frequency;
+    s->timers[1].frequency = s->frequency;
 
     qemu_get_timedate(&tm, 0);
     s->tick_offset = (uint32_t)mktimegm(&tm) + RTC_OFFSET;
@@ -713,6 +723,11 @@ static void cuda_initfn(Object *obj)
                         DEVICE(obj), "adb.0");
 }
 
+static Property cuda_properties[] = {
+    DEFINE_PROP_UINT64("frequency", CUDAState, frequency, 0),
+    DEFINE_PROP_END_OF_LIST()
+};
+
 static void cuda_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
@@ -720,6 +735,7 @@ static void cuda_class_init(ObjectClass *oc, void *data)
     dc->realize = cuda_realizefn;
     dc->reset = cuda_reset;
     dc->vmsd = &vmstate_cuda;
+    dc->props = cuda_properties;
 }
 
 static const TypeInfo cuda_type_info = {
diff --git a/hw/misc/macio/macio.c b/hw/misc/macio/macio.c
index 35eaa00..e0f1e88 100644
--- a/hw/misc/macio/macio.c
+++ b/hw/misc/macio/macio.c
@@ -42,6 +42,7 @@ typedef struct MacIOState
     void *dbdma;
     MemoryRegion *pic_mem;
     MemoryRegion *escc_mem;
+    uint64_t frequency;
 } MacIOState;
 
 #define OLDWORLD_MACIO(obj) \
@@ -351,12 +352,19 @@ static void macio_newworld_class_init(ObjectClass *oc, void *data)
     pdc->device_id = PCI_DEVICE_ID_APPLE_UNI_N_KEYL;
 }
 
+static Property macio_properties[] = {
+    DEFINE_PROP_UINT64("frequency", MacIOState, frequency, 0),
+    DEFINE_PROP_END_OF_LIST()
+};
+
 static void macio_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->vendor_id = PCI_VENDOR_ID_APPLE;
     k->class_id = PCI_CLASS_OTHERS << 8;
+    dc->props = macio_properties;
 }
 
 static const TypeInfo macio_oldworld_type_info = {
@@ -403,6 +411,8 @@ void macio_init(PCIDevice *d,
     macio_state->escc_mem = escc_mem;
     /* Note: this code is strongly inspirated from the corresponding code
        in PearPC */
+    qdev_prop_set_uint64(DEVICE(&macio_state->cuda), "frequency",
+                         macio_state->frequency);
 
     qdev_init_nofail(DEVICE(d));
 }
diff --git a/hw/ppc/mac.h b/hw/ppc/mac.h
index 23536f4..aff2b9a 100644
--- a/hw/ppc/mac.h
+++ b/hw/ppc/mac.h
@@ -57,6 +57,7 @@ typedef struct CUDATimer {
     uint16_t counter_value;
     int64_t load_time;
     int64_t next_irq_time;
+    uint64_t frequency;
     QEMUTimer *timer;
 } CUDATimer;
 
@@ -97,6 +98,7 @@ typedef struct CUDAState {
     CUDATimer timers[2];
 
     uint32_t tick_offset;
+    uint64_t frequency;
 
     uint8_t last_b;
     uint8_t last_acr;
diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
index 419d2b4..1eac3db 100644
--- a/hw/ppc/mac_newworld.c
+++ b/hw/ppc/mac_newworld.c
@@ -395,6 +395,7 @@ static void ppc_core99_init(MachineState *machine)
     qdev_connect_gpio_out(dev, 2, pic[0x02]); /* IDE DMA */
     qdev_connect_gpio_out(dev, 3, pic[0x0e]); /* IDE */
     qdev_connect_gpio_out(dev, 4, pic[0x03]); /* IDE DMA */
+    qdev_prop_set_uint64(dev, "frequency", tbfreq);
     macio_init(macio, pic_mem, escc_bar);
 
     /* We only emulate 2 out of 3 IDE controllers for now */
diff --git a/hw/ppc/mac_oldworld.c b/hw/ppc/mac_oldworld.c
index 8a6cec9..2e1bdc5 100644
--- a/hw/ppc/mac_oldworld.c
+++ b/hw/ppc/mac_oldworld.c
@@ -285,6 +285,7 @@ static void ppc_heathrow_init(MachineState *machine)
     qdev_connect_gpio_out(dev, 2, pic[0x02]); /* IDE-0 DMA */
     qdev_connect_gpio_out(dev, 3, pic[0x0E]); /* IDE-1 */
     qdev_connect_gpio_out(dev, 4, pic[0x03]); /* IDE-1 DMA */
+    qdev_prop_set_uint64(dev, "frequency", tbfreq);
     macio_init(macio, pic_mem, escc_bar);
 
     macio_ide = MACIO_IDE(object_resolve_path_component(OBJECT(macio),
-- 
1.8.1.4