Message ID | 20240220151035.327199-6-sebastianene@google.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | arm64: ptdump: View the second stage page-tables | expand |
On Tue, Feb 20, 2024 at 03:10:34PM +0000, Sebastian Ene wrote: > Define a set of attributes used by the ptdump parser to display the > properties of a guest memory region covered by a pagetable descriptor. > Build a description of the pagetable levels and initialize the parser > with this configuration. > > Signed-off-by: Sebastian Ene <sebastianene@google.com> > --- > arch/arm64/kvm/ptdump.c | 146 ++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 139 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c > index 9b04c24bb9be..2c4e0c122d23 100644 > --- a/arch/arm64/kvm/ptdump.c > +++ b/arch/arm64/kvm/ptdump.c > @@ -14,6 +14,61 @@ > #include <kvm_ptdump.h> > > > +#define MARKERS_LEN (2) > +#define KVM_PGTABLE_LEVELS (KVM_PGTABLE_LAST_LEVEL + 1) > + > +struct kvm_ptdump_guest_state { > + struct kvm *kvm; > + struct pg_state parser_state; > + struct addr_marker ipa_marker[MARKERS_LEN]; > + struct pg_level level[KVM_PGTABLE_LEVELS]; > + struct ptdump_range range[MARKERS_LEN]; > +}; > + > +static const struct prot_bits stage2_pte_bits[] = { > + { > + .mask = PTE_VALID, > + .val = PTE_VALID, > + .set = " ", > + .clear = "F", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, > + .set = "XN", > + .clear = " ", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, > + .set = "R", > + .clear = " ", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, > + .set = "W", > + .clear = " ", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, > + .set = "AF", > + .clear = " ", > + }, { > + .mask = PTE_NG, > + .val = PTE_NG, > + .set = "FnXS", > + .clear = " ", > + }, { > + .mask = PTE_CONT | PTE_VALID, > + .val = PTE_CONT | PTE_VALID, > + .set = "CON", > + .clear = " ", > + }, { > + .mask = PTE_TABLE_BIT, > + .val = PTE_TABLE_BIT, > + .set = " ", > + .clear = "BLK", > + }, > +}; > + > static int kvm_ptdump_visitor(const struct kvm_pgtable_visit_ctx *ctx, > enum kvm_pgtable_walk_flags visit) > { > @@ -37,15 +92,78 @@ static int kvm_ptdump_show_common(struct seq_file *m, > return kvm_pgtable_walk(pgtable, 0, BIT(pgtable->ia_bits), &walker); > } > > +static int kvm_ptdump_build_levels(struct pg_level *level, u32 start_lvl) > +{ > + static const char * const level_names[] = {"PGD", "PUD", "PMD", "PTE"}; > + u32 i = 0; > + u64 mask = 0; > + > + if (start_lvl > 2) { > + pr_err("invalid start_lvl %u\n", start_lvl); > + return -EINVAL; > + } > + > + for (i = 0; i < ARRAY_SIZE(stage2_pte_bits); i++) > + mask |= stage2_pte_bits[i].mask; > + > + for (i = start_lvl; i <= KVM_PGTABLE_LAST_LEVEL; i++) { > + level[i].name = level_names[i]; > + level[i].num = ARRAY_SIZE(stage2_pte_bits); > + level[i].bits = stage2_pte_bits; > + level[i].mask = mask; > + } > + > + if (start_lvl > 0) > + level[start_lvl].name = level_names[0]; > + > + return 0; > +} > + > +static struct kvm_ptdump_guest_state > +*kvm_ptdump_parser_init(struct kvm *kvm) > +{ > + struct kvm_ptdump_guest_state *st; > + struct kvm_s2_mmu *mmu = &kvm->arch.mmu; > + struct kvm_pgtable *pgtable = mmu->pgt; > + int ret; > + > + st = kzalloc(sizeof(struct kvm_ptdump_guest_state), GFP_KERNEL_ACCOUNT); > + if (!st) > + return NULL; > + > + ret = kvm_ptdump_build_levels(&st->level[0], pgtable->start_level); > + if (ret) > + goto free_with_state; > + > + st->ipa_marker[0].name = "Guest IPA"; > + st->ipa_marker[1].start_address = BIT(pgtable->ia_bits); > + st->range[0].end = BIT(pgtable->ia_bits); > + > + st->kvm = kvm; > + st->parser_state = (struct pg_state) { > + .marker = &st->ipa_marker[0], > + .level = -1, > + .pg_level = &st->level[0], > + .ptdump.range = &st->range[0], > + }; > + > + return st; > +free_with_state: > + kfree(st); > + return NULL; > +} > + > static int kvm_ptdump_guest_show(struct seq_file *m, void *) > { > - struct kvm *kvm = m->private; > + struct kvm_ptdump_guest_state *st = m->private; > + struct kvm *kvm = st->kvm; > struct kvm_s2_mmu *mmu = &kvm->arch.mmu; > - struct pg_state parser_state = {0}; > int ret; > > + st->parser_state.seq = m; > + > write_lock(&kvm->mmu_lock); > - ret = kvm_ptdump_show_common(m, mmu->pgt, &parser_state); > + ret = kvm_ptdump_show_common(m, mmu->pgt, &st->parser_state); > write_unlock(&kvm->mmu_lock); > > return ret; > @@ -54,22 +172,36 @@ static int kvm_ptdump_guest_show(struct seq_file *m, void *) > static int kvm_ptdump_guest_open(struct inode *m, struct file *file) > { > struct kvm *kvm = m->i_private; > + struct kvm_ptdump_guest_state *st; > int ret; > > - if (!kvm_get_kvm_safe(kvm)) > - return -ENOENT; FIXME: Keep kvm_get_kvm_safe before invoking kvm_ptdump_parser_init to avoid UAF if kvm gets destroyed. > + st = kvm_ptdump_parser_init(kvm); > + if (!st) > + return -ENOMEM; > > - ret = single_open(file, kvm_ptdump_guest_show, m->i_private); > + if (!kvm_get_kvm_safe(kvm)) { > + ret = -ENOENT; > + goto free_with_state; > + } > + > + ret = single_open(file, kvm_ptdump_guest_show, st); > if (ret < 0) > - kvm_put_kvm(kvm); > + goto free_with_kvm_ref; > > return ret; > +free_with_kvm_ref: > + kvm_put_kvm(kvm); > +free_with_state: > + kfree(st); > + return ret; > } > > static int kvm_ptdump_guest_close(struct inode *m, struct file *file) > { > struct kvm *kvm = m->i_private; > + void *st = ((struct seq_file *)file->private_data)->private; > > + kfree(st); > kvm_put_kvm(kvm); > return single_release(m, file); > } > -- > 2.44.0.rc0.258.g7320e95886-goog >
diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c index 9b04c24bb9be..2c4e0c122d23 100644 --- a/arch/arm64/kvm/ptdump.c +++ b/arch/arm64/kvm/ptdump.c @@ -14,6 +14,61 @@ #include <kvm_ptdump.h> +#define MARKERS_LEN (2) +#define KVM_PGTABLE_LEVELS (KVM_PGTABLE_LAST_LEVEL + 1) + +struct kvm_ptdump_guest_state { + struct kvm *kvm; + struct pg_state parser_state; + struct addr_marker ipa_marker[MARKERS_LEN]; + struct pg_level level[KVM_PGTABLE_LEVELS]; + struct ptdump_range range[MARKERS_LEN]; +}; + +static const struct prot_bits stage2_pte_bits[] = { + { + .mask = PTE_VALID, + .val = PTE_VALID, + .set = " ", + .clear = "F", + }, { + .mask = KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, + .val = KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, + .set = "XN", + .clear = " ", + }, { + .mask = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, + .val = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, + .set = "R", + .clear = " ", + }, { + .mask = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, + .val = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, + .set = "W", + .clear = " ", + }, { + .mask = KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, + .val = KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, + .set = "AF", + .clear = " ", + }, { + .mask = PTE_NG, + .val = PTE_NG, + .set = "FnXS", + .clear = " ", + }, { + .mask = PTE_CONT | PTE_VALID, + .val = PTE_CONT | PTE_VALID, + .set = "CON", + .clear = " ", + }, { + .mask = PTE_TABLE_BIT, + .val = PTE_TABLE_BIT, + .set = " ", + .clear = "BLK", + }, +}; + static int kvm_ptdump_visitor(const struct kvm_pgtable_visit_ctx *ctx, enum kvm_pgtable_walk_flags visit) { @@ -37,15 +92,78 @@ static int kvm_ptdump_show_common(struct seq_file *m, return kvm_pgtable_walk(pgtable, 0, BIT(pgtable->ia_bits), &walker); } +static int kvm_ptdump_build_levels(struct pg_level *level, u32 start_lvl) +{ + static const char * const level_names[] = {"PGD", "PUD", "PMD", "PTE"}; + u32 i = 0; + u64 mask = 0; + + if (start_lvl > 2) { + pr_err("invalid start_lvl %u\n", start_lvl); + return -EINVAL; + } + + for (i = 0; i < ARRAY_SIZE(stage2_pte_bits); i++) + mask |= stage2_pte_bits[i].mask; + + for (i = start_lvl; i <= KVM_PGTABLE_LAST_LEVEL; i++) { + level[i].name = level_names[i]; + level[i].num = ARRAY_SIZE(stage2_pte_bits); + level[i].bits = stage2_pte_bits; + level[i].mask = mask; + } + + if (start_lvl > 0) + level[start_lvl].name = level_names[0]; + + return 0; +} + +static struct kvm_ptdump_guest_state +*kvm_ptdump_parser_init(struct kvm *kvm) +{ + struct kvm_ptdump_guest_state *st; + struct kvm_s2_mmu *mmu = &kvm->arch.mmu; + struct kvm_pgtable *pgtable = mmu->pgt; + int ret; + + st = kzalloc(sizeof(struct kvm_ptdump_guest_state), GFP_KERNEL_ACCOUNT); + if (!st) + return NULL; + + ret = kvm_ptdump_build_levels(&st->level[0], pgtable->start_level); + if (ret) + goto free_with_state; + + st->ipa_marker[0].name = "Guest IPA"; + st->ipa_marker[1].start_address = BIT(pgtable->ia_bits); + st->range[0].end = BIT(pgtable->ia_bits); + + st->kvm = kvm; + st->parser_state = (struct pg_state) { + .marker = &st->ipa_marker[0], + .level = -1, + .pg_level = &st->level[0], + .ptdump.range = &st->range[0], + }; + + return st; +free_with_state: + kfree(st); + return NULL; +} + static int kvm_ptdump_guest_show(struct seq_file *m, void *) { - struct kvm *kvm = m->private; + struct kvm_ptdump_guest_state *st = m->private; + struct kvm *kvm = st->kvm; struct kvm_s2_mmu *mmu = &kvm->arch.mmu; - struct pg_state parser_state = {0}; int ret; + st->parser_state.seq = m; + write_lock(&kvm->mmu_lock); - ret = kvm_ptdump_show_common(m, mmu->pgt, &parser_state); + ret = kvm_ptdump_show_common(m, mmu->pgt, &st->parser_state); write_unlock(&kvm->mmu_lock); return ret; @@ -54,22 +172,36 @@ static int kvm_ptdump_guest_show(struct seq_file *m, void *) static int kvm_ptdump_guest_open(struct inode *m, struct file *file) { struct kvm *kvm = m->i_private; + struct kvm_ptdump_guest_state *st; int ret; - if (!kvm_get_kvm_safe(kvm)) - return -ENOENT; + st = kvm_ptdump_parser_init(kvm); + if (!st) + return -ENOMEM; - ret = single_open(file, kvm_ptdump_guest_show, m->i_private); + if (!kvm_get_kvm_safe(kvm)) { + ret = -ENOENT; + goto free_with_state; + } + + ret = single_open(file, kvm_ptdump_guest_show, st); if (ret < 0) - kvm_put_kvm(kvm); + goto free_with_kvm_ref; return ret; +free_with_kvm_ref: + kvm_put_kvm(kvm); +free_with_state: + kfree(st); + return ret; } static int kvm_ptdump_guest_close(struct inode *m, struct file *file) { struct kvm *kvm = m->i_private; + void *st = ((struct seq_file *)file->private_data)->private; + kfree(st); kvm_put_kvm(kvm); return single_release(m, file); }
Define a set of attributes used by the ptdump parser to display the properties of a guest memory region covered by a pagetable descriptor. Build a description of the pagetable levels and initialize the parser with this configuration. Signed-off-by: Sebastian Ene <sebastianene@google.com> --- arch/arm64/kvm/ptdump.c | 146 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 139 insertions(+), 7 deletions(-)