x86: allow Dom0 to drive PC speaker

Index: 2007-08-08/xen/arch/x86/domain_build.c
===================================================================
@@ -967,6 +967,8 @@ int __init construct_dom0(
     rc |= ioports_deny_access(dom0, 0xA0, 0xA1);
     /* Interval Timer (PIT). */
     rc |= ioports_deny_access(dom0, 0x40, 0x43);
+    if ( !using_pit )
+        rc |= ioports_permit_access(dom0, 0x42, 0x42);
     /* PIT Channel 2 / PC Speaker Control. */
     rc |= ioports_deny_access(dom0, 0x61, 0x61);
     /* Command-line I/O ranges. */

Index: 2007-08-08/xen/arch/x86/hvm/i8254.c
===================================================================
@@ -592,20 +592,49 @@ static int handle_speaker_io(ioreq_t *p)
     return 1;
 }
 
+#include <io_ports.h>
+
 int pv_pit_handler(int port, int data, int write)
 {
     ioreq_t ioreq = {
         .size = 1,
         .type = IOREQ_TYPE_PIO,
         .addr = port,
-        .dir  = write ? 0 : 1,
-        .data = write ? data : 0,
+        .dir  = write ? IOREQ_WRITE : IOREQ_READ,
+        .data = data
     };
 
     if ( port == 0x61 )
+    {
+        if ( !using_pit && current->domain->domain_id == 0 )
+        {
+            if ( !write )
+                return inb(0x61);
+            outb((inb(0x61) & ~3) | (data & 3), 0x61);
+            return 0;
+        }
         handle_speaker_io(&ioreq);
+    }
     else
+    {
+        if ( !using_pit && current->domain->domain_id == 0 &&
+             port == PIT_MODE && write )
+        {
+            switch ( data & 0xc0 )
+            {
+                case 0xc0: /* read back */
+                    outb(data & 0xf8, PIT_MODE);
+                    if ( !(data & 0x07) )
+                        return 0;
+                    data &= ~0x08;
+                    break;
+                case 0x80: /* counter 2 latch */
+                    outb(data, PIT_MODE);
+                    return 0;
+            }
+        }
         handle_pit_io(&ioreq);
+    }
 
     return !write ? ioreq.data : 0;
 }

Index: 2007-08-08/xen/arch/x86/time.c
===================================================================
@@ -38,6 +38,7 @@ string_param("clocksource", opt_clocksou
 #define EPOCH MILLISECS(1000)
 
 unsigned long cpu_khz;  /* CPU clock frequency in kHz. */
+int using_pit;
 unsigned long hpet_address;
 DEFINE_SPINLOCK(rtc_lock);
 volatile unsigned long jiffies;

@@ -177,7 +178,6 @@ static u64 init_pit_and_calibrate_tsc(vo
     unsigned long count;
 
     /* Set PIT channel 0 to HZ Hz. */
-#define CLOCK_TICK_RATE 1193180 /* crystal freq (Hz) */
 #define LATCH (((CLOCK_TICK_RATE)+(HZ/2))/HZ)
     outb_p(0x34, PIT_MODE);        /* binary, mode 2, LSB/MSB, ch 0 */
     outb_p(LATCH & 0xff, PIT_CH0); /* LSB */

@@ -308,6 +308,7 @@ static void init_pit(struct platform_tim
     pts->frequency = CLOCK_TICK_RATE;
     pts->read_counter = read_pit_count;
     pts->counter_bits = 16;
+    using_pit = 1;
 }
 
 /************************************************************

Index: 2007-08-08/xen/include/asm-x86/time.h
===================================================================
@@ -4,6 +4,8 @@
 
 #include <asm/msr.h>
 
+extern int using_pit;
+
 extern void calibrate_tsc_bp(void);
 extern void calibrate_tsc_ap(void);