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AJvYcCW1WlMWnYV29GSbmkRLWqsMhblR+sU4TMTpQ54q8kxTmoEuiy3Rm4IFM/T8aa5fdM+sFfKvVlgNU90UCIExjWW7@lists.infradead.org X-Gm-Message-State: AOJu0Yyo3FkobO//9uD1284YEAIB/omf69+MGwD/SsRccUupHOjbfhtb SUUJKQyqlPpU4mpZkZN3rmK1RwW7gp9ScA76aQJkx4e1HJ4MK3Rx8SypLenkLPzBw3oRnE69TlO IruypbSbQ0JLzWWonLr5M9pwCyA== X-Google-Smtp-Source: AGHT+IFxiVGmxV1SeAk+rQ6esRUKQhSaio0jNBDqtfLxXEnyCJ7jXIY6+34UXYrhIaHuXVBZH+t7RQIgxN3TiCrDbaI= X-Received: from sebkvm.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:cd5]) (user=sebastianene job=sendgmr) by 2002:a81:7e46:0:b0:664:c5e0:6574 with SMTP id 00721157ae682-6cfbbbd63c4mr960687b3.9.1724748367933; Tue, 27 Aug 2024 01:46:07 -0700 (PDT) Date: Tue, 27 Aug 2024 08:45:47 +0000 In-Reply-To: <20240827084549.45731-1-sebastianene@google.com> Mime-Version: 1.0 References: <20240827084549.45731-1-sebastianene@google.com> X-Mailer: git-send-email 2.46.0.295.g3b9ea8a38a-goog Message-ID: <20240827084549.45731-5-sebastianene@google.com> Subject: [PATCH v9 4/5] 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240827_014610_151507_350CC4FC X-CRM114-Status: GOOD ( 22.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. 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/Makefile | 1 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/ptdump.c | 247 ++++++++++++++++++++++++++++++ 4 files changed, 255 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) == 1; \ }) +#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/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 += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o kvm-$(CONFIG_ARM64_PTR_AUTH) += pauth.o +kvm-$(CONFIG_PTDUMP_STAGE2_DEBUGFS) += ptdump.o always-y := hyp_constants.h hyp-constants.s 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, struct vm_fault *vmf) void kvm_arch_create_vm_debugfs(struct kvm *kvm) { kvm_sys_regs_create_debugfs(kvm); + kvm_s2_ptdump_create_debugfs(kvm); } 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..e72a928d4445 --- /dev/null +++ b/arch/arm64/kvm/ptdump.c @@ -0,0 +1,247 @@ +// 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[] = { + { + .mask = PTE_VALID, + .val = PTE_VALID, + .set = " ", + .clear = "F", + }, { + .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_HI_S2_XN | PTE_VALID, + .val = PTE_VALID, + .set = " ", + .clear = "X", + }, { + .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_TABLE_BIT | PTE_VALID, + .val = PTE_VALID, + .set = "BLK", + .clear = " ", + }, +}; + +static int kvm_ptdump_visitor(const struct kvm_pgtable_visit_ctx *ctx, + enum kvm_pgtable_walk_flags visit) +{ + struct ptdump_pg_state *st = ctx->arg; + struct ptdump_state *pt_st = &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 start_lvl) +{ + u32 i; + u64 mask; + + if (WARN_ON_ONCE(start_lvl >= KVM_PGTABLE_LAST_LEVEL)) + return -EINVAL; + + mask = 0; + for (i = 0; i < ARRAY_SIZE(stage2_pte_bits); i++) + mask |= stage2_pte_bits[i].mask; + + for (i = start_lvl; i < KVM_PGTABLE_MAX_LEVELS; i++) { + snprintf(level[i].name, sizeof(level[i].name), "%d", i); + + level[i].num = ARRAY_SIZE(stage2_pte_bits); + level[i].bits = stage2_pte_bits; + level[i].mask = 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 = &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 ERR_PTR(-ENOMEM); + + ret = kvm_ptdump_build_levels(&st->level[0], pgtable->start_level); + if (ret) { + kfree(st); + return ERR_PTR(ret); + } + + 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 ptdump_pg_state) { + .marker = &st->ipa_marker[0], + .level = -1, + .pg_level = &st->level[0], + .ptdump.range = &st->range[0], + .start_address = 0, + }; + + return st; +} + +static int kvm_ptdump_guest_show(struct seq_file *m, void *unused) +{ + int ret; + struct kvm_ptdump_guest_state *st = m->private; + struct kvm *kvm = st->kvm; + struct kvm_s2_mmu *mmu = &kvm->arch.mmu; + struct ptdump_pg_state *parser_state = &st->parser_state; + struct kvm_pgtable_walker walker = (struct kvm_pgtable_walker) { + .cb = kvm_ptdump_visitor, + .arg = parser_state, + .flags = KVM_PGTABLE_WALK_LEAF, + }; + + parser_state->seq = m; + + write_lock(&kvm->mmu_lock); + ret = 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 = m->i_private; + struct kvm_ptdump_guest_state *st; + int ret; + + if (!kvm_get_kvm_safe(kvm)) + return -ENOENT; + + st = kvm_ptdump_parser_create(kvm); + if (IS_ERR(st)) { + ret = PTR_ERR(st); + goto free_with_kvm_ref; + } + + ret = single_open(file, kvm_ptdump_guest_show, st); + if (!ret) + return 0; + + kfree(st); +free_with_kvm_ref: + kvm_put_kvm(kvm); + 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); +} + +static const struct file_operations kvm_ptdump_guest_fops = { + .open = kvm_ptdump_guest_open, + .read = seq_read, + .llseek = seq_lseek, + .release = kvm_ptdump_guest_close, +}; + +static int kvm_pgtable_debugfs_show(struct seq_file *m, void *unused) +{ + const struct file *file = m->file; + struct kvm_pgtable *pgtable = m->private; + + if (!strcmp(file_dentry(file)->d_iname, "ipa_range")) + seq_printf(m, "%2u\n", pgtable->ia_bits); + else if (!strcmp(file_dentry(file)->d_iname, "stage2_levels")) + seq_printf(m, "%1d\n", KVM_PGTABLE_LAST_LEVEL - pgtable->start_level + 1); + return 0; +} + +static int kvm_pgtable_debugfs_open(struct inode *m, struct file *file) +{ + struct kvm *kvm = m->i_private; + struct kvm_pgtable *pgtable; + int ret; + + if (!kvm_get_kvm_safe(kvm)) + return -ENOENT; + + pgtable = kvm->arch.mmu.pgt; + + ret = single_open(file, kvm_pgtable_debugfs_show, pgtable); + if (ret < 0) + kvm_put_kvm(kvm); + return ret; +} + +static int kvm_pgtable_debugfs_close(struct inode *m, struct file *file) +{ + struct kvm *kvm = m->i_private; + + kvm_put_kvm(kvm); + return single_release(m, file); +} + +static const struct file_operations kvm_pgtable_debugfs_fops = { + .open = kvm_pgtable_debugfs_open, + .read = seq_read, + .llseek = seq_lseek, + .release = 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_debugfs_fops); + debugfs_create_file("stage2_levels", 0400, kvm->debugfs_dentry, + kvm, &kvm_pgtable_debugfs_fops); +}