The PIC code makes little effort to avoid kvm_vcpu_kick(), resulting in
unnecessary guest exits in some conditions.
For example, if the timer interrupt is routed through the IOAPIC, IRR
for IRQ 0 will get set but not cleared, since the APIC is handling the
acks.
This means that everytime an interrupt < 16 is triggered, the priority
logic will find IRQ0 pending and send an IPI to vcpu0 (in case IRQ0 is
not masked, which is Linux's case).
Introduce a new variable isr_ack to represent the IRQ's for which the
guest has been signalled / cleared the ISR. Use it to avoid more than
one IPI per trigger-ack cycle, in addition to the avoidance when ISR is
set in get_priority().
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The irq ack during pic reset has three problems:
- Ignores slave/master PIC, using gsi 0-8 for both.
- Generates an ACK even if the APIC is in control.
- Depends upon IMR being clear, which is broken if the irq was masked
at the time it was generated.
The last one causes the BIOS to hang after the first reboot of
Windows installation, since PIT interrupts stop.
[avi: fix check whether pic interrupts are seen by cpu]
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Based on a patch from: Ben-Ami Yassour <benami@il.ibm.com>
which was based on a patch from: Amit Shah <amit.shah@qumranet.com>
Notify IRQ acking on PIC/APIC emulation. The previous patch missed two things:
- Edge triggered interrupts on IOAPIC
- PIC reset with IRR/ISR set should be equivalent to ack (LAPIC probably
needs something similar).
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
CC: Amit Shah <amit.shah@qumranet.com>
CC: Ben-Ami Yassour <benami@il.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Modify member in_range() of structure kvm_io_device to pass length and the type
of the I/O (write or read).
This modification allows to use kvm_io_device with coalesced MMIO.
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This paves the way for multiple architecture support. Note that while
ioapic.c could potentially be shared with ia64, it is also moved.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Marcelo Tosatti
Avi Kivity
Ben-Ami Yassour
Laurent Vivier