KVM: arm64: ptdump: Fix shadow ptdump sleep-in-atomic-context problem

Previously we exposed shadow page tables by creating a debugfs ptdump
file whenever a nested mmu instance gets bound to a new context, and
deleting the debugfs file whose context was getting unbound.

This turned out to be buggy, as the instance<->context binding process
is done with the mmu_lock held, and debugfs creation/deletion can sleep.

Change the approach and create a shadow ptdump file for each nested mmu
instead during kvm_vcpu_init_nested(), in a sleepable context. The files
will be named nested_mmu<index>, and reading it will return the nested
context's VTTBR, VTCR, and s2 enabled or not before dumping the shadow
page tables, given the nested mmu is valid.

Fixes: 19e15dc73f0f ("KVM: arm64: nv: Expose shadow page tables in debugfs")
Reported-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Closes: https://lore.kernel.org/kvmarm/aiuF0KSvvv-ZozI1@sm-arm-grace07/
Tested-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Signed-off-by: Wei-Lin Chang <weilin.chang@arm.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260924094951.727352-3-weilin.chang@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

0 files changed, 0 insertions, 0 deletions