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KVM: arm64: ptdump: Initialize parser_state before pgtable walk

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If we go through the "need a bigger buffer" path in seq_read_iter(), which
is likely to happen as we're dumping page tables, we will pass the
populated-by-last-run st::parser_state to
kvm_pgtable_walk()/kvm_ptdump_visitor(). As a result, the output of
stage2_page_tables on my box looks like

0x0000000240000000-0x0000000000000000   17179869175G 1
0x0000000000000000-0x0000000000200000           2M 2   R   px ux  AF BLK
0x0000000000200000-0x0000000040000000        1022M 2
0x0000000040000000-0x0000000040200000           2M 2   R W PXNUXN AF BLK
[...]

Fix it by always initializing st::parser_state before starting a new
pgtable walk.

Besides, remove st::range as it's not used by note_page(); remove the
explicit initialization of parser_state::start_address as it will be
initialized in note_page() anyway.

Signed-off-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>
Link: https://patch.msgid.link/20260328053155.12219-1-zenghui.yu@linux.dev
[maz: rebased on top of NV support]
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Zenghui Yu (Huawei)
2026-03-28 13:31:55 +08:00
committed by Marc Zyngier
parent 19e15dc73f
commit 570428601b
1 changed files with 7 additions and 13 deletions
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20
arch/arm64/kvm/ptdump.c
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@@ -24,7 +24,6 @@ struct kvm_ptdump_guest_state {
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[] = {
@@ -132,17 +131,8 @@ static struct kvm_ptdump_guest_state *kvm_ptdump_parser_create(struct kvm_s2_mmu
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->mmu = mmu;
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;
}
@@ -152,14 +142,18 @@ static int kvm_ptdump_guest_show(struct seq_file *m, void *unused)
struct kvm_ptdump_guest_state *st = m->private;
struct kvm_s2_mmu *mmu = st->mmu;
struct kvm *kvm = kvm_s2_mmu_to_kvm(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,
.arg = &st->parser_state,
.flags = KVM_PGTABLE_WALK_LEAF,
};
parser_state->seq = m;
st->parser_state = (struct ptdump_pg_state) {
.marker = &st->ipa_marker[0],
.level = -1,
.pg_level = &st->level[0],
.seq = m,
};
write_lock(&kvm->mmu_lock);
ret = kvm_pgtable_walk(mmu->pgt, 0, BIT(mmu->pgt->ia_bits), &walker);