On Mon, 2022-12-05 at 23:25 +0100, Philippe Mathieu-Daudé wrote: > On 5/12/22 18:31, David Woodhouse wrote: > > From: Ankur Arora < > > ankur.a.ar...@oracle.com > > > > > > > GSI-2/IOAPIC pin-2 is treated specially while initing > > IRQ routing: PIC does not use it at all while the IOAPIC > > maps virq=0 to pin-2 and does not use GSI-2. > > (all other GSIs are identity mapped to pins.) > > > > This results in any later code which allocates a virq > > to be assigned GSI-2. This virq is in-turn used to > > remap interrupts to HYPERVISOR_CALLBACK_VECTOR (0xf3) > > to deliver to the guest. > > > > Ordinarily this would be okay, but if the event delivery is > > via direct injection via KVM_REQ_EVENT (without going > > through the LAPIC) we see vmentry failure. > > > > This works fine for any other values of GSI. > > > > As a workaround, mark GSI-2 used. > > > > Signed-off-by: Ankur Arora <ankur.a.ar...@oracle.com> > > Signed-off-by: David Woodhouse <d...@amazon.co.uk> > > --- > > accel/kvm/kvm-all.c | 5 +++++ > > hw/i386/kvm/ioapic.c | 1 + > > include/sysemu/kvm.h | 1 + > > 3 files changed, 7 insertions(+) > > > > diff --git a/hw/i386/kvm/ioapic.c b/hw/i386/kvm/ioapic.c > > index ee7c8ef68b..5fab0d35c9 100644 > > --- a/hw/i386/kvm/ioapic.c > > +++ b/hw/i386/kvm/ioapic.c > > @@ -43,6 +43,7 @@ void kvm_pc_setup_irq_routing(bool pci_enabled) > > } > > } > > } > > Workarounds usually deserve some comment in the code.
Yes, good point. Although I actually think I can kill this off completely since we no longer attempt the deliver the vector directly with KVM_REQ_EVENT anyway; the kernel injects it *for* us when it sees that vcpu_info->evtchn_upcall_pending is set on entry to the guest vCPU. > > + kvm_irqchip_set_gsi(s, 2); > > kvm_irqchip_commit_routes(s); > > }
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