When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

This cleans up the error handling a lot, as this code will never get
hit.

Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim KrÄmář" <rkrcmar@redhat.com>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

As Jan reported [1], lockdep complains about the VGIC not being bullet
proof. This seems to be due to two issues:
- When commit 006df0f3 ("KVM: arm/arm64: Support calling
  vgic_update_irq_pending from irq context") promoted irq_lock and
  ap_list_lock to _irqsave, we forgot two instances of irq_lock.
  lockdeps seems to pick those up.
- If a lock is _irqsave, any other locks we take inside them should be
  _irqsafe as well. So the lpi_list_lock needs to be promoted also.

This fixes both issues by simply making the remaining instances of those
locks _irqsave.
One irq_lock is addressed in a separate patch, to simplify backporting.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-May/575718.html

Cc: stable@vger.kernel.org
Fixes: 006df0f3 ("KVM: arm/arm64: Support calling vgic_update_irq_pending from irq context")
Reported-by: NJan Glauber <jan.glauber@caviumnetworks.com>
Acked-by: NChristoffer Dall <christoffer.dall@arm.com>
Signed-off-by: NAndre Przywara <andre.przywara@arm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

vgic_debug_seq_ops and file_operations are not supposed to change
at runtime and none of the structures is modified.
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NChristoffer Dall <cdall@linaro.org>

Add a file to debugfs to read the in-kernel state of the vgic.  We don't
do any locking of the entire VGIC state while traversing all the IRQs,
so if the VM is running the user/developer may not see a quiesced state,
but should take care to pause the VM using facilities in user space for
that purpose.

We also don't support LPIs yet, but they can be added easily if needed.
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Tested-by: NEric Auger <eric.auger@redhat.com>
Tested-by: NAndre Przywara <andre.przywara@arm.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>