On Mon, 3 Jun 2019 17:27:40 +0200
Cornelia Huck [off-list ref] wrote:

On Wed, 29 May 2019 14:26:53 +0200
Michael Mueller [off-list ref] wrote:

quoted

From: Halil Pasic <pasic@linux.ibm.com>

Protected virtualization guests have to use shared pages for airq
notifier bit vectors, because hypervisor needs to write these bits.

Let us make sure we allocate DMA memory for the notifier bit vectors by
replacing the kmem_cache with a dma_cache and kalloc() with
cio_dma_zalloc().

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Sebastian Ott <redacted>
Signed-off-by: Michael Mueller <redacted>
---
 arch/s390/include/asm/airq.h |  2 ++
 drivers/s390/cio/airq.c      | 32 ++++++++++++++++++++------------
 drivers/s390/cio/cio.h       |  2 ++
 drivers/s390/cio/css.c       |  1 +
 4 files changed, 25 insertions(+), 12 deletions(-)

Apologies if that already has been answered (and I missed it in my mail
pile...), but two things had come to my mind previously:

- CHSC... does anything need to be done there? Last time I asked:
  "Anyway, css_bus_init() uses some chscs
   early (before cio_dma_pool_init), so we could not use the pools
   there, even if we wanted to. Do chsc commands either work, or else
   fail benignly on a protected virt guest?"

Protected virt won't support all CHSC. The supported ones won't requre
use of shared memory. So we are fine.

- PCI indicators... does this interact with any dma configuration on
  the pci device? (I know pci is not supported yet, and I don't really
  expect any problems.)

It does but, I'm pretty confident we don't have a problem with PCI. IMHO
Sebastian is the guy who needs to be paranoid about this, and he r-b-ed
the respective patches.

Regards,
Halil