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-rw-r--r--arch/x86/kvm/mtrr.c699
1 files changed, 699 insertions, 0 deletions
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
new file mode 100644
index 000000000000..de1d2d8062e2
--- /dev/null
+++ b/arch/x86/kvm/mtrr.c
@@ -0,0 +1,699 @@
+/*
+ * vMTRR implementation
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affiliates.
+ * Copyright(C) 2015 Intel Corporation.
+ *
+ * Authors:
+ * Yaniv Kamay <yaniv@qumranet.com>
+ * Avi Kivity <avi@qumranet.com>
+ * Marcelo Tosatti <mtosatti@redhat.com>
+ * Paolo Bonzini <pbonzini@redhat.com>
+ * Xiao Guangrong <guangrong.xiao@linux.intel.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include <linux/kvm_host.h>
+#include <asm/mtrr.h>
+
+#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 msr_mtrr_valid(unsigned msr)
+{
+ switch (msr) {
+ case 0x200 ... 0x200 + 2 * 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:
+ case MSR_IA32_CR_PAT:
+ return true;
+ case 0x2f8:
+ return true;
+ }
+ return false;
+}
+
+static bool valid_pat_type(unsigned t)
+{
+ return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
+}
+
+static bool valid_mtrr_type(unsigned t)
+{
+ return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
+}
+
+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_IA32_CR_PAT) {
+ for (i = 0; i < 8; i++)
+ if (!valid_pat_type((data >> (i * 8)) & 0xff))
+ return false;
+ return true;
+ } else 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 >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR));
+
+ mask = (~0ULL) << cpuid_maxphyaddr(vcpu);
+ if ((msr & 1) == 0) {
+ /* MTRR base */
+ if (!valid_mtrr_type(data & 0xff))
+ return false;
+ mask |= 0xf00;
+ } else
+ /* MTRR mask */
+ mask |= 0x7ff;
+ if (data & mask) {
+ kvm_inject_gp(vcpu, 0);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(kvm_mtrr_valid);
+
+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;
+}
+
+/*
+* 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 = msr - MSR_MTRRfix16K_80000;
+ break;
+ case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000:
+ *seg = 2;
+ *unit = msr - MSR_MTRRfix4K_C0000;
+ 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;
+ mask |= ~0ULL << boot_cpu_data.x86_phys_bits;
+
+ /* 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;
+ int index;
+
+ if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
+ !kvm_arch_has_noncoherent_dma(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. */
+ index = (msr - 0x200) / 2;
+ var_mtrr_range(&mtrr_state->var_ranges[index], &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;
+ int index, is_mtrr_mask;
+
+ index = (msr - 0x200) / 2;
+ is_mtrr_mask = msr - 0x200 - 2 * index;
+ cur = &mtrr_state->var_ranges[index];
+
+ /* remove the entry if it's in the list. */
+ if (var_mtrr_range_is_valid(cur))
+ list_del(&mtrr_state->var_ranges[index].node);
+
+ if (!is_mtrr_mask)
+ cur->base = data;
+ else
+ cur->mask = data;
+
+ /* 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 if (msr == MSR_IA32_CR_PAT)
+ vcpu->arch.pat = 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 if (msr == MSR_IA32_CR_PAT)
+ *pdata = vcpu->arch.pat;
+ else { /* Variable MTRRs */
+ int is_mtrr_mask;
+
+ index = (msr - 0x200) / 2;
+ is_mtrr_mask = msr - 0x200 - 2 * index;
+ if (!is_mtrr_mask)
+ *pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
+ else
+ *pdata = vcpu->arch.mtrr_state.var_ranges[index].mask;
+ }
+
+ 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;
+ /* [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 = 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->partial_map = 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->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;
+ }
+
+ /* It is not covered by MTRRs. */
+ if (iter.partial_map) {
+ /*
+ * We just check one page, partially covered by MTRRs is
+ * impossible.
+ */
+ WARN_ON(type != -1);
+ type = mtrr_default_type(mtrr_state);
+ }
+ 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.partial_map)
+ return true;
+
+ if (type == -1)
+ return true;
+
+ return type == mtrr_default_type(mtrr_state);
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.