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// Initialize MTRRs - mostly useful on KVM.
//
// Copyright (C) 2006 Fabrice Bellard
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "util.h" // dprintf
#include "config.h" // CONFIG_*
#include "xen.h" // usingXen
#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)
#define MTRR_MEMTYPE_UC 0
#define MTRR_MEMTYPE_WC 1
#define MTRR_MEMTYPE_WT 4
#define MTRR_MEMTYPE_WP 5
#define MTRR_MEMTYPE_WB 6
void mtrr_setup(void)
{
if (!CONFIG_MTRR_INIT || CONFIG_COREBOOT || usingXen())
return;
u32 eax, ebx, ecx, edx, cpuid_features;
cpuid(1, &eax, &ebx, &ecx, &cpuid_features);
if (!(cpuid_features & CPUID_MTRR))
return;
if (!(cpuid_features & CPUID_MSR))
return;
dprintf(3, "init mtrr\n");
u32 mtrr_cap = rdmsr(MSR_MTRRcap);
int vcnt = mtrr_cap & 0xff;
int fix = mtrr_cap & 0x100;
if (!vcnt || !fix)
return;
// Disable MTRRs
wrmsr_smp(MSR_MTRRdefType, 0);
// Set fixed MTRRs
union u64b {
u8 valb[8];
u64 val;
} u;
u.val = 0;
int i;
for (i = 0; i < 8; i++)
if (RamSize >= 65536 * (i + 1))
u.valb[i] = MTRR_MEMTYPE_WB;
wrmsr_smp(MSR_MTRRfix64K_00000, u.val);
u.val = 0;
for (i = 0; i < 8; i++)
if (RamSize >= 0x80000 + 16384 * (i + 1))
u.valb[i] = MTRR_MEMTYPE_WB;
wrmsr_smp(MSR_MTRRfix16K_80000, u.val);
wrmsr_smp(MSR_MTRRfix16K_A0000, 0); // 0xA0000-0xC0000 is uncached
int j;
for (j = 0; j < 8; j++) {
u.val = 0;
for (i = 0; i < 8; i++)
if (RamSize >= 0xC0000 + j * 0x8000 + 4096 * (i + 1))
u.valb[i] = MTRR_MEMTYPE_WP;
wrmsr_smp(MSR_MTRRfix4K_C0000 + j, u.val);
}
// Set variable MTRRs
int phys_bits = 36;
cpuid(0x80000000u, &eax, &ebx, &ecx, &edx);
if (eax >= 0x80000008) {
/* Get physical bits from leaf 0x80000008 (if available) */
cpuid(0x80000008u, &eax, &ebx, &ecx, &edx);
phys_bits = eax & 0xff;
}
u64 phys_mask = ((1ull << phys_bits) - 1);
for (i=0; i<vcnt; i++) {
wrmsr_smp(MTRRphysBase_MSR(i), 0);
wrmsr_smp(MTRRphysMask_MSR(i), 0);
}
/* Mark 3.5-4GB as UC, anything not specified defaults to WB */
wrmsr_smp(MTRRphysBase_MSR(0), BUILD_MAX_HIGHMEM | MTRR_MEMTYPE_UC);
wrmsr_smp(MTRRphysMask_MSR(0)
, (-((1ull<<32)-BUILD_MAX_HIGHMEM) & phys_mask) | 0x800);
// Enable fixed and variable MTRRs; set default type.
wrmsr_smp(MSR_MTRRdefType, 0xc00 | MTRR_MEMTYPE_WB);
}
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