From 48070c73058be6de9c0d754d441ed7092dfc8f12 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Mon, 30 Oct 2017 14:38:58 +0100 Subject: s390/pci: do not require AIS facility 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 Reviewed-by: Pierre Morel Reviewed-by: Halil Pasic Acked-by: Sebastian Ott Signed-off-by: Heiko Carstens --- arch/s390/include/asm/pci_insn.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/s390/include/asm') diff --git a/arch/s390/include/asm/pci_insn.h b/arch/s390/include/asm/pci_insn.h index 34abcf2..a74efc0 100644 --- a/arch/s390/include/asm/pci_insn.h +++ b/arch/s390/include/asm/pci_insn.h @@ -81,6 +81,6 @@ int zpci_refresh_trans(u64 fn, u64 addr, u64 range); int zpci_load(u64 *data, u64 req, u64 offset); int zpci_store(u64 data, u64 req, u64 offset); int zpci_store_block(const u64 *data, u64 req, u64 offset); -void zpci_set_irq_ctrl(u16 ctl, char *unused, u8 isc); +int zpci_set_irq_ctrl(u16 ctl, char *unused, u8 isc); #endif -- cgit v1.1