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AJvYcCUkluno89T1XUAVT0S5eoAnBDF5qw0ikiUJP2c7L2ygSx9DmEVNqusMPpjH75Z98d0ZnWz9XOvD6Ssj5oU=@vger.kernel.org X-Gm-Message-State: AOJu0YztNsRIB2S1qeDrTelFd6PDEBN0oO5D67Q+HEyNkKcYBzW56MEr l50+f+Cc9XdSzL56EW6ZMRbTe/UnIn8IbFRhZyyzlMdJchRT2ZodvDO8EFMPvzd97lPTwPE4XTC eiWAvT95r+ofmYrp+3S5+/Ik7nw== X-Google-Smtp-Source: AGHT+IFrv0rLDSOUyf6zXDI606xTRZ7fv0Nwzc81o52OBg6AUGVDlns9tuVUU3FDCSkjPXyyiudbP0Q4hvSoN0F+igM= X-Received: from sebkvm.c.googlers.com ([fda3:e722:ac3:cc00:68:fe9:ac10:f1b7]) (user=sebastianene job=sendgmr) by 2002:a05:6000:184f:b0:374:cade:3806 with SMTP id ffacd0b85a97d-378895c5256mr15705f8f.2.1725886056876; Mon, 09 Sep 2024 05:47:36 -0700 (PDT) Date: Mon, 9 Sep 2024 12:47:21 +0000 In-Reply-To: <20240909124721.1672199-1-sebastianene@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240909124721.1672199-1-sebastianene@google.com> X-Mailer: git-send-email 2.46.0.469.g59c65b2a67-goog Message-ID: <20240909124721.1672199-6-sebastianene@google.com> Subject: [PATCH v10 5/5] KVM: arm64: Register ptdump with debugfs on guest creation From: Sebastian Ene To: akpm@linux-foundation.org, alexghiti@rivosinc.com, ankita@nvidia.com, ardb@kernel.org, catalin.marinas@arm.com, christophe.leroy@csgroup.eu, james.morse@arm.com, vdonnefort@google.com, mark.rutland@arm.com, maz@kernel.org, oliver.upton@linux.dev, rananta@google.com, ryan.roberts@arm.com, sebastianene@google.com, shahuang@redhat.com, suzuki.poulose@arm.com, will@kernel.org, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" While arch/*/mem/ptdump handles the kernel pagetable dumping code, introduce KVM/ptdump to show the guest stage-2 pagetables. The separation is necessary because most of the definitions from the stage-2 pagetable reside in the KVM path and we will be invoking functionality specific to KVM. Introduce the PTDUMP_STAGE2_DEBUGFS config. When a guest is created, register a new file entry under the guest debugfs dir which allows userspace to show the contents of the guest stage-2 pagetables when accessed. Signed-off-by: Sebastian Ene Reviewed-by: Vincent Donnefort --- arch/arm64/include/asm/kvm_host.h | 6 + arch/arm64/kvm/Kconfig | 17 ++ arch/arm64/kvm/Makefile | 1 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/ptdump.c | 268 ++++++++++++++++++++++++++++++ 5 files changed, 293 insertions(+) create mode 100644 arch/arm64/kvm/ptdump.c diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h index a33f5996ca9f..4acd589f086b 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1473,4 +1473,10 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64= val); (pa + pi + pa3) =3D=3D 1; \ }) =20 +#ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS +void kvm_s2_ptdump_create_debugfs(struct kvm *kvm); +#else +static inline void kvm_s2_ptdump_create_debugfs(struct kvm *kvm) {} +#endif /* CONFIG_PTDUMP_STAGE2_DEBUGFS */ + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 8304eb342be9..ead632ad01b4 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -66,4 +66,21 @@ config PROTECTED_NVHE_STACKTRACE =20 If unsure, or not using protected nVHE (pKVM), say N. =20 +config PTDUMP_STAGE2_DEBUGFS + bool "Present the stage-2 pagetables to debugfs" + depends on KVM + depends on DEBUG_KERNEL + depends on DEBUG_FS + depends on GENERIC_PTDUMP + select PTDUMP_CORE + default n + help + Say Y here if you want to show the stage-2 kernel pagetables + layout in a debugfs file. This information is only useful for kernel de= velopers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + + If in doubt, say N. + endif # VIRTUALIZATION diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 86a629aaf0a1..e4233b323a73 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -27,6 +27,7 @@ kvm-y +=3D arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.= o \ =20 kvm-$(CONFIG_HW_PERF_EVENTS) +=3D pmu-emul.o pmu.o kvm-$(CONFIG_ARM64_PTR_AUTH) +=3D pauth.o +kvm-$(CONFIG_PTDUMP_STAGE2_DEBUGFS) +=3D ptdump.o =20 always-y :=3D hyp_constants.h hyp-constants.s =20 diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 9bef7638342e..b9fd928d3477 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -228,6 +228,7 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, s= truct vm_fault *vmf) void kvm_arch_create_vm_debugfs(struct kvm *kvm) { kvm_sys_regs_create_debugfs(kvm); + kvm_s2_ptdump_create_debugfs(kvm); } =20 static void kvm_destroy_mpidr_data(struct kvm *kvm) diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c new file mode 100644 index 000000000000..e29604a864b7 --- /dev/null +++ b/arch/arm64/kvm/ptdump.c @@ -0,0 +1,268 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Debug helper used to dump the stage-2 pagetables of the system and their + * associated permissions. + * + * Copyright (C) Google, 2024 + * Author: Sebastian Ene + */ +#include +#include +#include + +#include +#include +#include + +#define MARKERS_LEN 2 +#define KVM_PGTABLE_MAX_LEVELS (KVM_PGTABLE_LAST_LEVEL + 1) + +struct kvm_ptdump_guest_state { + struct kvm *kvm; + struct ptdump_pg_state parser_state; + struct addr_marker ipa_marker[MARKERS_LEN]; + struct ptdump_pg_level level[KVM_PGTABLE_MAX_LEVELS]; + struct ptdump_range range[MARKERS_LEN]; +}; + +static const struct ptdump_prot_bits stage2_pte_bits[] =3D { + { + .mask =3D PTE_VALID, + .val =3D PTE_VALID, + .set =3D " ", + .clear =3D "F", + }, { + .mask =3D KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, + .val =3D KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, + .set =3D "R", + .clear =3D " ", + }, { + .mask =3D KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, + .val =3D KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, + .set =3D "W", + .clear =3D " ", + }, { + .mask =3D KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, + .val =3D PTE_VALID, + .set =3D " ", + .clear =3D "X", + }, { + .mask =3D KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, + .val =3D KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, + .set =3D "AF", + .clear =3D " ", + }, { + .mask =3D PTE_TABLE_BIT | PTE_VALID, + .val =3D PTE_VALID, + .set =3D "BLK", + .clear =3D " ", + }, +}; + +static int kvm_ptdump_visitor(const struct kvm_pgtable_visit_ctx *ctx, + enum kvm_pgtable_walk_flags visit) +{ + struct ptdump_pg_state *st =3D ctx->arg; + struct ptdump_state *pt_st =3D &st->ptdump; + + note_page(pt_st, ctx->addr, ctx->level, ctx->old); + + return 0; +} + +static int kvm_ptdump_build_levels(struct ptdump_pg_level *level, u32 star= t_lvl) +{ + u32 i; + u64 mask; + + if (WARN_ON_ONCE(start_lvl >=3D KVM_PGTABLE_LAST_LEVEL)) + return -EINVAL; + + mask =3D 0; + for (i =3D 0; i < ARRAY_SIZE(stage2_pte_bits); i++) + mask |=3D stage2_pte_bits[i].mask; + + for (i =3D start_lvl; i < KVM_PGTABLE_MAX_LEVELS; i++) { + snprintf(level[i].name, sizeof(level[i].name), "%u", i); + + level[i].num =3D ARRAY_SIZE(stage2_pte_bits); + level[i].bits =3D stage2_pte_bits; + level[i].mask =3D mask; + } + + return 0; +} + +static struct kvm_ptdump_guest_state *kvm_ptdump_parser_create(struct kvm = *kvm) +{ + struct kvm_ptdump_guest_state *st; + struct kvm_s2_mmu *mmu =3D &kvm->arch.mmu; + struct kvm_pgtable *pgtable =3D mmu->pgt; + int ret; + + st =3D kzalloc(sizeof(struct kvm_ptdump_guest_state), GFP_KERNEL_ACCOUNT); + if (!st) + return ERR_PTR(-ENOMEM); + + ret =3D kvm_ptdump_build_levels(&st->level[0], pgtable->start_level); + if (ret) { + kfree(st); + return ERR_PTR(ret); + } + + st->ipa_marker[0].name =3D "Guest IPA"; + st->ipa_marker[1].start_address =3D BIT(pgtable->ia_bits); + st->range[0].end =3D BIT(pgtable->ia_bits); + + st->kvm =3D kvm; + st->parser_state =3D (struct ptdump_pg_state) { + .marker =3D &st->ipa_marker[0], + .level =3D -1, + .pg_level =3D &st->level[0], + .ptdump.range =3D &st->range[0], + .start_address =3D 0, + }; + + return st; +} + +static int kvm_ptdump_guest_show(struct seq_file *m, void *unused) +{ + int ret; + struct kvm_ptdump_guest_state *st =3D m->private; + struct kvm *kvm =3D st->kvm; + struct kvm_s2_mmu *mmu =3D &kvm->arch.mmu; + struct ptdump_pg_state *parser_state =3D &st->parser_state; + struct kvm_pgtable_walker walker =3D (struct kvm_pgtable_walker) { + .cb =3D kvm_ptdump_visitor, + .arg =3D parser_state, + .flags =3D KVM_PGTABLE_WALK_LEAF, + }; + + parser_state->seq =3D m; + + write_lock(&kvm->mmu_lock); + ret =3D kvm_pgtable_walk(mmu->pgt, 0, BIT(mmu->pgt->ia_bits), &walker); + write_unlock(&kvm->mmu_lock); + + return ret; +} + +static int kvm_ptdump_guest_open(struct inode *m, struct file *file) +{ + struct kvm *kvm =3D m->i_private; + struct kvm_ptdump_guest_state *st; + int ret; + + if (!kvm_get_kvm_safe(kvm)) + return -ENOENT; + + st =3D kvm_ptdump_parser_create(kvm); + if (IS_ERR(st)) { + ret =3D PTR_ERR(st); + goto err_with_kvm_ref; + } + + ret =3D single_open(file, kvm_ptdump_guest_show, st); + if (!ret) + return 0; + + kfree(st); +err_with_kvm_ref: + kvm_put_kvm(kvm); + return ret; +} + +static int kvm_ptdump_guest_close(struct inode *m, struct file *file) +{ + struct kvm *kvm =3D m->i_private; + void *st =3D ((struct seq_file *)file->private_data)->private; + + kfree(st); + kvm_put_kvm(kvm); + + return single_release(m, file); +} + +static const struct file_operations kvm_ptdump_guest_fops =3D { + .open =3D kvm_ptdump_guest_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D kvm_ptdump_guest_close, +}; + +static int kvm_pgtable_range_show(struct seq_file *m, void *unused) +{ + struct kvm_pgtable *pgtable =3D m->private; + + seq_printf(m, "%2u\n", pgtable->ia_bits); + return 0; +} + +static int kvm_pgtable_levels_show(struct seq_file *m, void *unused) +{ + struct kvm_pgtable *pgtable =3D m->private; + + seq_printf(m, "%1d\n", KVM_PGTABLE_MAX_LEVELS - pgtable->start_level); + return 0; +} + +static int kvm_pgtable_debugfs_open(struct inode *m, struct file *file, + int (*show)(struct seq_file *, void *)) +{ + struct kvm *kvm =3D m->i_private; + struct kvm_pgtable *pgtable; + int ret; + + if (!kvm_get_kvm_safe(kvm)) + return -ENOENT; + + pgtable =3D kvm->arch.mmu.pgt; + + ret =3D single_open(file, show, pgtable); + if (ret < 0) + kvm_put_kvm(kvm); + return ret; +} + +static int kvm_pgtable_range_open(struct inode *m, struct file *file) +{ + return kvm_pgtable_debugfs_open(m, file, kvm_pgtable_range_show); +} + +static int kvm_pgtable_levels_open(struct inode *m, struct file *file) +{ + return kvm_pgtable_debugfs_open(m, file, kvm_pgtable_levels_show); +} + +static int kvm_pgtable_debugfs_close(struct inode *m, struct file *file) +{ + struct kvm *kvm =3D m->i_private; + + kvm_put_kvm(kvm); + return single_release(m, file); +} + +static const struct file_operations kvm_pgtable_range_fops =3D { + .open =3D kvm_pgtable_range_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D kvm_pgtable_debugfs_close, +}; + +static const struct file_operations kvm_pgtable_levels_fops =3D { + .open =3D kvm_pgtable_levels_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D kvm_pgtable_debugfs_close, +}; + +void kvm_s2_ptdump_create_debugfs(struct kvm *kvm) +{ + debugfs_create_file("stage2_page_tables", 0400, kvm->debugfs_dentry, + kvm, &kvm_ptdump_guest_fops); + debugfs_create_file("ipa_range", 0400, kvm->debugfs_dentry, kvm, + &kvm_pgtable_range_fops); + debugfs_create_file("stage2_levels", 0400, kvm->debugfs_dentry, + kvm, &kvm_pgtable_levels_fops); +} --=20 2.46.0.469.g59c65b2a67-goog