android_kernel_oneplus_msm8998/arch/s390/pci
Christian Borntraeger 93f45d8c67 s390/pci: do not require AIS facility
[ Upstream commit 48070c73058be6de9c0d754d441ed7092dfc8f12 ]

As of today QEMU does not provide the AIS facility to its guest.  This
prevents Linux guests from using PCI devices as the ais facility is
checked during init. As this is just a performance optimization, we can
move the ais check into the code where we need it (calling the SIC
instruction). This is used at initialization and on interrupt. Both
places do not require any serialization, so we can simply skip the
instruction.

Since we will now get all interrupts, we can also avoid the 2nd scan.
As we can have multiple interrupts in parallel we might trigger spurious
irqs more often for the non-AIS case but the core code can handle that.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-09 18:42:39 +01:00
..
Makefile s390/kernel: add system calls for PCI memory access 2014-11-19 09:46:43 +01:00
pci.c s390/pci: do not require AIS facility 2017-12-09 18:42:39 +01:00
pci_clp.c s390/pci: improve irq number check for msix 2014-11-03 13:30:12 +01:00
pci_debug.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2015-04-20 10:15:33 -07:00
pci_dma.c s390/pci: fix use after free in dma_init 2017-03-26 12:13:18 +02:00
pci_event.c s390/pci: use pci_rescan_remove_lock 2015-07-29 09:11:56 +02:00
pci_insn.c s390/pci: do not require AIS facility 2017-12-09 18:42:39 +01:00
pci_mmio.c s390/pci: fix possible information leak in mmio syscall 2015-02-26 09:24:48 +01:00
pci_sysfs.c s390/pci: use pci_rescan_remove_lock 2015-07-29 09:11:56 +02:00