[PATCH v6 5/6] KVM: arm64: Initialize the ptdump parser with stage-2 attributes

[Sebastian Ene]

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 at 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;
+	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