x86/PCI/MSI: Make sure that irq reservation mode works everywhere

If interrupt reservation mode is enabled then the PCI/MSI interrupts must be reactivated after early activation.

Make sure that all callers of pci_msi_create_irq_domain() have the MSI_FLAG_MUST_REACTIVATE set when reservation mode is enabled.

Signed-off-by Thomas Gleixner <[email protected]>

---
 drivers/pci/msi.c |    2 ++
 1 file changed, 2 insertions(+)

Quoted 8 lines

From: Thomas Gleixner [mailto:[email protected]]
Sent: Tuesday, October 17, 2017 12:55 AM

arch/x86/Kconfig +0 -0

@@ -95,7 +95,7 @@ config X86
 	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
 	select GENERIC_IRQ_MIGRATION		if SMP
 	select GENERIC_IRQ_PROBE

arch/x86/Kconfig config X86 · line 101

Quoted 5 lines

arch/x86/Kconfig +1 -1

-	select GENERIC_IRQ_SHOW
+	select GENERIC_IRQ_RESERVATION_MODE
 	select GENERIC_PENDING_IRQ		if SMP
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_STRNCPY_FROM_USER

Hi Thomas,
It looks you removed GENERIC_IRQ_SHOW by accident?

I got this build error:
...
LD vmlinux.o
MODPOST vmlinux.o
fs/proc/interrupts.o:(.rodata+0x118): undefined reference to `show_interrupts' Makefile:1000: recipe for target 'vmlinux' failed
make: *** [vmlinux] Error 1

Adding GENERIC_IRQ_SHOW back can fix the build failure, and with the pachset Hyper-V PCI pass-through can work fine.

Dexuan reported that the recent rework of the vector allocation mode in x86 broke HyperV PCI passtrough because the rework missed to add the MSI_FLAG_MUST_REACTIVATE flag to the HyperV/PCI interrupt domain info.

The simple solution would be to set the flag in the HyperV/PCI driver but it's better to make this generic and let the PCI/MSI core code set the flag when reservation mode is enabled. That ensures that future users of this wont trip over the same problem.

Thanks,

tglx

---
 arch/x86/Kconfig           |    2 +-
 arch/x86/kernel/apic/msi.c |    5 ++---
 drivers/pci/msi.c          |    2 ++
 kernel/irq/Kconfig         |    3 +++
 4 files changed, 8 insertions(+), 4 deletions(-)

Quoted 11 lines · Thomas Gleixner

Dexuan reported that the recent rework of the vector allocation mode in x86 broke HyperV PCI passtrough because the rework missed to add the MSI_FLAG_MUST_REACTIVATE flag to the HyperV/PCI interrupt domain info.

The simple solution would be to set the flag in the HyperV/PCI driver but it's better to make this generic and let the PCI/MSI core code set the flag when reservation mode is enabled. That ensures that future users of this wont trip over the same problem.

Thanks,

Quoted 8 lines

tglx

---
 arch/x86/Kconfig           |    2 +-
 arch/x86/kernel/apic/msi.c |    5 ++---
 drivers/pci/msi.c          |    2 ++
 kernel/irq/Kconfig         |    3 +++
 4 files changed, 8 insertions(+), 4 deletions(-)

This mentions 4900be83602b ("x86/vector/msi: Switch to global reservation mode"), which I don't have, so I assume it's an x86 thing. So I guess you'll probably merge this via the same tree?