// SPDX-License-Identifier: GPL-2.0-only /* * vMTRR implementation * * Copyright (C) 2006 Qumranet, Inc. * Copyright 2010 Red Hat, Inc. and/or its affiliates. * Copyright(C) 2015 Intel Corporation. * * Authors: * Yaniv Kamay * Avi Kivity * Marcelo Tosatti * Paolo Bonzini * Xiao Guangrong */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include "cpuid.h" #include "mmu.h" #define IA32_MTRR_DEF_TYPE_E (1ULL << 11) #define IA32_MTRR_DEF_TYPE_FE (1ULL << 10) #define IA32_MTRR_DEF_TYPE_TYPE_MASK (0xff) static bool is_mtrr_base_msr(unsigned int msr) { /* MTRR base MSRs use even numbers, masks use odd numbers. */ return !(msr & 0x1); } static struct kvm_mtrr_range *var_mtrr_msr_to_range(struct kvm_vcpu *vcpu, unsigned int msr) { int index = (msr - MTRRphysBase_MSR(0)) / 2; return &vcpu->arch.mtrr_state.var_ranges[index]; } static bool msr_mtrr_valid(unsigned msr) { switch (msr) { case MTRRphysBase_MSR(0) ... MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1): case MSR_MTRRfix64K_00000: case MSR_MTRRfix16K_80000: case MSR_MTRRfix16K_A0000: case MSR_MTRRfix4K_C0000: case MSR_MTRRfix4K_C8000: case MSR_MTRRfix4K_D0000: case MSR_MTRRfix4K_D8000: case MSR_MTRRfix4K_E0000: case MSR_MTRRfix4K_E8000: case MSR_MTRRfix4K_F0000: case MSR_MTRRfix4K_F8000: case MSR_MTRRdefType: return true; } return false; } static bool valid_mtrr_type(unsigned t) { return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */ } static bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) { int i; u64 mask; if (!msr_mtrr_valid(msr)) return false; if (msr == MSR_MTRRdefType) { if (data & ~0xcff) return false; return valid_mtrr_type(data & 0xff); } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) { for (i = 0; i < 8 ; i++) if (!valid_mtrr_type((data >> (i * 8)) & 0xff)) return false; return true; } /* variable MTRRs */ WARN_ON(!(msr >= MTRRphysBase_MSR(0) && msr <= MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1))); mask = kvm_vcpu_reserved_gpa_bits_raw(vcpu); if ((msr & 1) == 0) { /* MTRR base */ if (!valid_mtrr_type(data & 0xff)) return false; mask |= 0xf00; } else /* MTRR mask */ mask |= 0x7ff; return (data & mask) == 0; } static bool mtrr_is_enabled(struct kvm_mtrr *mtrr_state) { return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_E); } static bool fixed_mtrr_is_enabled(struct kvm_mtrr *mtrr_state) { return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_FE); } static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state) { return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK; } static u8 mtrr_disabled_type(struct kvm_vcpu *vcpu) { /* * Intel SDM 11.11.2.2: all MTRRs are disabled when * IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC * memory type is applied to all of physical memory. * * However, virtual machines can be run with CPUID such that * there are no MTRRs. In that case, the firmware will never * enable MTRRs and it is obviously undesirable to run the * guest entirely with UC memory and we use WB. */ if (guest_cpuid_has(vcpu, X86_FEATURE_MTRR)) return MTRR_TYPE_UNCACHABLE; else return MTRR_TYPE_WRBACK; } /* * Three terms are used in the following code: * - segment, it indicates the address segments covered by fixed MTRRs. * - unit, it corresponds to the MSR entry in the segment. * - range, a range is covered in one memory cache type. */ struct fixed_mtrr_segment { u64 start; u64 end; int range_shift; /* the start position in kvm_mtrr.fixed_ranges[]. */ int range_start; }; static struct fixed_mtrr_segment fixed_seg_table[] = { /* MSR_MTRRfix64K_00000, 1 unit. 64K fixed mtrr. */ { .start = 0x0, .end = 0x80000, .range_shift = 16, /* 64K */ .range_start = 0, }, /* * MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000, 2 units, * 16K fixed mtrr. */ { .start = 0x80000, .end = 0xc0000, .range_shift = 14, /* 16K */ .range_start = 8, }, /* * MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000, 8 units, * 4K fixed mtrr. */ { .start = 0xc0000, .end = 0x100000, .range_shift = 12, /* 12K */ .range_start = 24, } }; /* * The size of unit is covered in one MSR, one MSR entry contains * 8 ranges so that unit size is always 8 * 2^range_shift. */ static u64 fixed_mtrr_seg_unit_size(int seg) { return 8 << fixed_seg_table[seg].range_shift; } static bool fixed_msr_to_seg_unit(u32 msr, int *seg, int *unit) { switch (msr) { case MSR_MTRRfix64K_00000: *seg = 0; *unit = 0; break; case MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000: *seg = 1; *unit = array_index_nospec( msr - MSR_MTRRfix16K_80000, MSR_MTRRfix16K_A0000 - MSR_MTRRfix16K_80000 + 1); break; case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000: *seg = 2; *unit = array_index_nospec( msr - MSR_MTRRfix4K_C0000, MSR_MTRRfix4K_F8000 - MSR_MTRRfix4K_C0000 + 1); break; default: return false; } return true; } static void fixed_mtrr_seg_unit_range(int seg, int unit, u64 *start, u64 *end) { struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg]; u64 unit_size = fixed_mtrr_seg_unit_size(seg); *start = mtrr_seg->start + unit * unit_size; *end = *start + unit_size; WARN_ON(*end > mtrr_seg->end); } static int fixed_mtrr_seg_unit_range_index(int seg, int unit) { struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg]; WARN_ON(mtrr_seg->start + unit * fixed_mtrr_seg_unit_size(seg) > mtrr_seg->end); /* each unit has 8 ranges. */ return mtrr_seg->range_start + 8 * unit; } static int fixed_mtrr_seg_end_range_index(int seg) { struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg]; int n; n = (mtrr_seg->end - mtrr_seg->start) >> mtrr_seg->range_shift; return mtrr_seg->range_start + n - 1; } static bool fixed_msr_to_range(u32 msr, u64 *start, u64 *end) { int seg, unit; if (!fixed_msr_to_seg_unit(msr, &seg, &unit)) return false; fixed_mtrr_seg_unit_range(seg, unit, start, end); return true; } static int fixed_msr_to_range_index(u32 msr) { int seg, unit; if (!fixed_msr_to_seg_unit(msr, &seg, &unit)) return -1; return fixed_mtrr_seg_unit_range_index(seg, unit); } static int fixed_mtrr_addr_to_seg(u64 addr) { struct fixed_mtrr_segment *mtrr_seg; int seg, seg_num = ARRAY_SIZE(fixed_seg_table); for (seg = 0; seg < seg_num; seg++) { mtrr_seg = &fixed_seg_table[seg]; if (mtrr_seg->start <= addr && addr < mtrr_seg->end) return seg; } return -1; } static int fixed_mtrr_addr_seg_to_range_index(u64 addr, int seg) { struct fixed_mtrr_segment *mtrr_seg; int index; mtrr_seg = &fixed_seg_table[seg]; index = mtrr_seg->range_start; index += (addr - mtrr_seg->start) >> mtrr_seg->range_shift; return index; } static u64 fixed_mtrr_range_end_addr(int seg, int index) { struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg]; int pos = index - mtrr_seg->range_start; return mtrr_seg->start + ((pos + 1) << mtrr_seg->range_shift); } static void var_mtrr_range(struct kvm_mtrr_range *range, u64 *start, u64 *end) { u64 mask; *start = range->base & PAGE_MASK; mask = range->mask & PAGE_MASK; /* This cannot overflow because writing to the reserved bits of * variable MTRRs causes a #GP. */ *end = (*start | ~mask) + 1; } static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr) { struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state; gfn_t start, end; if (!kvm_mmu_honors_guest_mtrrs(vcpu->kvm)) return; if (!mtrr_is_enabled(mtrr_state) && msr != MSR_MTRRdefType) return; /* fixed MTRRs. */ if (fixed_msr_to_range(msr, &start, &end)) { if (!fixed_mtrr_is_enabled(mtrr_state)) return; } else if (msr == MSR_MTRRdefType) { start = 0x0; end = ~0ULL; } else { /* variable range MTRRs. */ var_mtrr_range(var_mtrr_msr_to_range(vcpu, msr), &start, &end); } kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end)); } static bool var_mtrr_range_is_valid(struct kvm_mtrr_range *range) { return (range->mask & (1 << 11)) != 0; } static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data) { struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state; struct kvm_mtrr_range *tmp, *cur; cur = var_mtrr_msr_to_range(vcpu, msr); /* remove the entry if it's in the list. */ if (var_mtrr_range_is_valid(cur)) list_del(&cur->node); /* * Set all illegal GPA bits in the mask, since those bits must * implicitly be 0. The bits are then cleared when reading them. */ if (is_mtrr_base_msr(msr)) cur->base = data; else cur->mask = data | kvm_vcpu_reserved_gpa_bits_raw(vcpu); /* add it to the list if it's enabled. */ if (var_mtrr_range_is_valid(cur)) { list_for_each_entry(tmp, &mtrr_state->head, node) if (cur->base >= tmp->base) break; list_add_tail(&cur->node, &tmp->node); } } int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data) { int index; if (!kvm_mtrr_valid(vcpu, msr, data)) return 1; index = fixed_msr_to_range_index(msr); if (index >= 0) *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index] = data; else if (msr == MSR_MTRRdefType) vcpu->arch.mtrr_state.deftype = data; else set_var_mtrr_msr(vcpu, msr, data); update_mtrr(vcpu, msr); return 0; } int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) { int index; /* MSR_MTRRcap is a readonly MSR. */ if (msr == MSR_MTRRcap) { /* * SMRR = 0 * WC = 1 * FIX = 1 * VCNT = KVM_NR_VAR_MTRR */ *pdata = 0x500 | KVM_NR_VAR_MTRR; return 0; } if (!msr_mtrr_valid(msr)) return 1; index = fixed_msr_to_range_index(msr); if (index >= 0) { *pdata = *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index]; } else if (msr == MSR_MTRRdefType) { *pdata = vcpu->arch.mtrr_state.deftype; } else { /* Variable MTRRs */ if (is_mtrr_base_msr(msr)) *pdata = var_mtrr_msr_to_range(vcpu, msr)->base; else *pdata = var_mtrr_msr_to_range(vcpu, msr)->mask; *pdata &= ~kvm_vcpu_reserved_gpa_bits_raw(vcpu); } return 0; } void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu) { INIT_LIST_HEAD(&vcpu->arch.mtrr_state.head); } struct mtrr_iter { /* input fields. */ struct kvm_mtrr *mtrr_state; u64 start; u64 end; /* output fields. */ int mem_type; /* mtrr is completely disabled? */ bool mtrr_disabled; /* [start, end) is not fully covered in MTRRs? */ bool partial_map; /* private fields. */ union { /* used for fixed MTRRs. */ struct { int index; int seg; }; /* used for var MTRRs. */ struct { struct kvm_mtrr_range *range; /* max address has been covered in var MTRRs. */ u64 start_max; }; }; bool fixed; }; static bool mtrr_lookup_fixed_start(struct mtrr_iter *iter) { int seg, index; if (!fixed_mtrr_is_enabled(iter->mtrr_state)) return false; seg = fixed_mtrr_addr_to_seg(iter->start); if (seg < 0) return false; iter->fixed = true; index = fixed_mtrr_addr_seg_to_range_index(iter->start, seg); iter->index = index; iter->seg = seg; return true; } static bool match_var_range(struct mtrr_iter *iter, struct kvm_mtrr_range *range) { u64 start, end; var_mtrr_range(range, &start, &end); if (!(start >= iter->end || end <= iter->start)) { iter->range = range; /* * the function is called when we do kvm_mtrr.head walking. * Range has the minimum base address which interleaves * [looker->start_max, looker->end). */ iter->partial_map |= iter->start_max < start; /* update the max address has been covered. */ iter->start_max = max(iter->start_max, end); return true; } return false; } static void __mtrr_lookup_var_next(struct mtrr_iter *iter) { struct kvm_mtrr *mtrr_state = iter->mtrr_state; list_for_each_entry_continue(iter->range, &mtrr_state->head, node) if (match_var_range(iter, iter->range)) return; iter->range = NULL; iter->partial_map |= iter->start_max < iter->end; } static void mtrr_lookup_var_start(struct mtrr_iter *iter) { struct kvm_mtrr *mtrr_state = iter->mtrr_state; iter->fixed = false; iter->start_max = iter->start; iter->range = NULL; iter->range = list_prepare_entry(iter->range, &mtrr_state->head, node); __mtrr_lookup_var_next(iter); } static void mtrr_lookup_fixed_next(struct mtrr_iter *iter) { /* terminate the lookup. */ if (fixed_mtrr_range_end_addr(iter->seg, iter->index) >= iter->end) { iter->fixed = false; iter->range = NULL; return; } iter->index++; /* have looked up for all fixed MTRRs. */ if (iter->index >= ARRAY_SIZE(iter->mtrr_state->fixed_ranges)) return mtrr_lookup_var_start(iter); /* switch to next segment. */ if (iter->index > fixed_mtrr_seg_end_range_index(iter->seg)) iter->seg++; } static void mtrr_lookup_var_next(struct mtrr_iter *iter) { __mtrr_lookup_var_next(iter); } static void mtrr_lookup_start(struct mtrr_iter *iter) { if (!mtrr_is_enabled(iter->mtrr_state)) { iter->mtrr_disabled = true; return; } if (!mtrr_lookup_fixed_start(iter)) mtrr_lookup_var_start(iter); } static void mtrr_lookup_init(struct mtrr_iter *iter, struct kvm_mtrr *mtrr_state, u64 start, u64 end) { iter->mtrr_state = mtrr_state; iter->start = start; iter->end = end; iter->mtrr_disabled = false; iter->partial_map = false; iter->fixed = false; iter->range = NULL; mtrr_lookup_start(iter); } static bool mtrr_lookup_okay(struct mtrr_iter *iter) { if (iter->fixed) { iter->mem_type = iter->mtrr_state->fixed_ranges[iter->index]; return true; } if (iter->range) { iter->mem_type = iter->range->base & 0xff; return true; } return false; } static void mtrr_lookup_next(struct mtrr_iter *iter) { if (iter->fixed) mtrr_lookup_fixed_next(iter); else mtrr_lookup_var_next(iter); } #define mtrr_for_each_mem_type(_iter_, _mtrr_, _gpa_start_, _gpa_end_) \ for (mtrr_lookup_init(_iter_, _mtrr_, _gpa_start_, _gpa_end_); \ mtrr_lookup_okay(_iter_); mtrr_lookup_next(_iter_)) u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn) { struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state; struct mtrr_iter iter; u64 start, end; int type = -1; const int wt_wb_mask = (1 << MTRR_TYPE_WRBACK) | (1 << MTRR_TYPE_WRTHROUGH); start = gfn_to_gpa(gfn); end = start + PAGE_SIZE; mtrr_for_each_mem_type(&iter, mtrr_state, start, end) { int curr_type = iter.mem_type; /* * Please refer to Intel SDM Volume 3: 11.11.4.1 MTRR * Precedences. */ if (type == -1) { type = curr_type; continue; } /* * If two or more variable memory ranges match and the * memory types are identical, then that memory type is * used. */ if (type == curr_type) continue; /* * If two or more variable memory ranges match and one of * the memory types is UC, the UC memory type used. */ if (curr_type == MTRR_TYPE_UNCACHABLE) return MTRR_TYPE_UNCACHABLE; /* * If two or more variable memory ranges match and the * memory types are WT and WB, the WT memory type is used. */ if (((1 << type) & wt_wb_mask) && ((1 << curr_type) & wt_wb_mask)) { type = MTRR_TYPE_WRTHROUGH; continue; } /* * For overlaps not defined by the above rules, processor * behavior is undefined. */ /* We use WB for this undefined behavior. :( */ return MTRR_TYPE_WRBACK; } if (iter.mtrr_disabled) return mtrr_disabled_type(vcpu); /* not contained in any MTRRs. */ if (type == -1) return mtrr_default_type(mtrr_state); /* * We just check one page, partially covered by MTRRs is * impossible. */ WARN_ON(iter.partial_map); return type; } EXPORT_SYMBOL_GPL(kvm_mtrr_get_guest_memory_type); bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int page_num) { struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state; struct mtrr_iter iter; u64 start, end; int type = -1; start = gfn_to_gpa(gfn); end = gfn_to_gpa(gfn + page_num); mtrr_for_each_mem_type(&iter, mtrr_state, start, end) { if (type == -1) { type = iter.mem_type; continue; } if (type != iter.mem_type) return false; } if (iter.mtrr_disabled) return true; if (!iter.partial_map) return true; if (type == -1) return true; return type == mtrr_default_type(mtrr_state); }