// 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 <[email protected]>
*/
#include <linux/debugfs.h>
#include <linux/kvm_host.h>
#include <linux/seq_file.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_pgtable.h>
#include <asm/ptdump.h>
#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), "%u", 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 err_with_kvm_ref;
}
ret = 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 = 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_range_show(struct seq_file *m, void *unused)
{
struct kvm_pgtable *pgtable = 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 = 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 = 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, 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 = m->i_private;
kvm_put_kvm(kvm);
return single_release(m, file);
}
static const struct file_operations kvm_pgtable_range_fops = {
.open = kvm_pgtable_range_open,
.read = seq_read,
.llseek = seq_lseek,
.release = kvm_pgtable_debugfs_close,
};
static const struct file_operations kvm_pgtable_levels_fops = {
.open = kvm_pgtable_levels_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_range_fops);
debugfs_create_file("stage2_levels", 0400, kvm->debugfs_dentry,
kvm, &kvm_pgtable_levels_fops);
}
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