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linux/arch/s390/pci
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Christian Borntraeger 3dde14f7f7 s390/pci: do not require AIS facility 
[ Upstream commit 48070c7305 ]

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>
History 2017-12-10 13:40:38 +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 2017-12-10 13:40:38 +01:00
pci_clp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci_debug.c s390/atomic: refactor atomic primitives 2016-11-11 16:37:33 +01:00
pci_dma.c This is the first pull request for the new dma-mapping subsystem 2017-07-06 19:20:54 -07:00
pci_event.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci_insn.c s390/pci: do not require AIS facility 2017-12-10 13:40:38 +01:00
pci_mmio.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci_sysfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00