add mtrr support (Avi Kivity)

program mtrrs for cpu 0.  Doesn't support >=4G at the moment.
    
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Index: bochs/bios/rombios32.c
===================================================================
--- bochs.orig/bios/rombios32.c
+++ bochs/bios/rombios32.c
@@ -64,6 +64,23 @@ typedef unsigned long long uint64_t;

 #define BIOS_TMP_STORAGE  0x00030000 /* 64 KB used to copy the BIOS to shadow RAM */

+#define MSR_MTRRcap			0x000000fe
+#define MSR_MTRRfix64K_00000		0x00000250
+#define MSR_MTRRfix16K_80000		0x00000258
+#define MSR_MTRRfix16K_A0000		0x00000259
+#define MSR_MTRRfix4K_C0000		0x00000268
+#define MSR_MTRRfix4K_C8000		0x00000269
+#define MSR_MTRRfix4K_D0000		0x0000026a
+#define MSR_MTRRfix4K_D8000		0x0000026b
+#define MSR_MTRRfix4K_E0000		0x0000026c
+#define MSR_MTRRfix4K_E8000		0x0000026d
+#define MSR_MTRRfix4K_F0000		0x0000026e
+#define MSR_MTRRfix4K_F8000		0x0000026f
+#define MSR_MTRRdefType			0x000002ff
+
+#define MTRRphysBase_MSR(reg) (0x200 + 2 * (reg))
+#define MTRRphysMask_MSR(reg) (0x200 + 2 * (reg) + 1)
+
 static inline void outl(int addr, int val)
 {
     asm volatile ("outl %1, %w0" : : "d" (addr), "a" (val));
@@ -135,6 +152,19 @@ static inline void putc(int c)
     outb(INFO_PORT, c);
 }

+static uint64_t rdmsr(unsigned index)
+{
+    unsigned long long ret;
+
+    asm ("rdmsr" : "=A"(ret) : "c"(index));
+    return ret;
+}
+
+static void wrmsr(unsigned index, uint64_t val)
+{
+    asm volatile ("wrmsr" : : "c"(index), "A"(val));
+}
+
 static inline int isdigit(int c)
 {
     return c >= '0' && c <= '9';
@@ -469,6 +499,54 @@ static int cmos_readb(int addr)
     return inb(0x71);
 }

+void setup_mtrr(void)
+{
+    int i, vcnt, fix, wc;
+    uint32_t mtrr_cap;
+    union {
+        uint8_t valb[8];
+        uint64_t val;
+    } u;
+    uint64_t vbase, vmask;
+
+    mtrr_cap = rdmsr(MSR_MTRRcap);
+    vcnt = mtrr_cap & 0xff;
+    fix = mtrr_cap & 0x100;
+    wc = mtrr_cap & 0x400;
+    if (!vcnt || !fix)
+	return;
+    u.val = 0;
+    for (i = 0; i < 8; ++i)
+        if (ram_size >= 65536 * (i + 1))
+            u.valb[i] = 6;
+    wrmsr(MSR_MTRRfix64K_00000, u.val);
+    u.val = 0;
+    for (i = 0; i < 8; ++i)
+        if (ram_size >= 65536 * 8 + 16384 * (i + 1))
+            u.valb[i] = 6;
+    wrmsr(MSR_MTRRfix16K_80000, u.val);
+    wrmsr(MSR_MTRRfix16K_A0000, 0);
+    wrmsr(MSR_MTRRfix4K_C0000, 0);
+    wrmsr(MSR_MTRRfix4K_C8000, 0);
+    wrmsr(MSR_MTRRfix4K_D0000, 0);
+    wrmsr(MSR_MTRRfix4K_D8000, 0);
+    wrmsr(MSR_MTRRfix4K_E0000, 0);
+    wrmsr(MSR_MTRRfix4K_E8000, 0);
+    wrmsr(MSR_MTRRfix4K_F0000, 0);
+    wrmsr(MSR_MTRRfix4K_F8000, 0);
+    vbase = 0;
+    --vcnt; /* leave one mtrr for VRAM */
+    for (i = 0; i < vcnt && vbase < ram_size; ++i) {
+        vmask = (1ull << 40) - 1;
+        while (vbase + vmask + 1 > ram_size)
+            vmask >>= 1;
+        wrmsr(MTRRphysBase_MSR(i), vbase | 6);
+        wrmsr(MTRRphysMask_MSR(i), (~vmask & 0xfffffff000ull) | 0x800);
+        vbase += vmask + 1;
+    }
+    wrmsr(MSR_MTRRdefType, 0xc00);
+}
+
 void ram_probe(void)
 {
   if (cmos_readb(0x34) | cmos_readb(0x35))
@@ -482,6 +560,7 @@ void ram_probe(void)
   ebda_cur_addr = ((*(uint16_t *)(0x40e)) << 4) + 0x380;
   BX_INFO("ebda_cur_addr: 0x%08lx\n", ebda_cur_addr);
 #endif
+  setup_mtrr();
 }

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