Merge branch 'xenfv-kvm-15' of git://git.infradead.org/users/dwmw2/qemu into HEAD

This adds support for emulating Xen under Linux/KVM, based on kernel
patches which have been present since Linux v5.12. As with the kernel
support, it's derived from work started by João Martins of Oracle in
2018.

This series just adds the basic platform support — CPUID, hypercalls,
event channels, a stub of XenStore.

A full single-tenant internal implementation of XenStore, and patches
to make QEMU's Xen PV drivers work with this Xen emulation, are waiting
in the wings to be submitted in a follow-on patch series.

As noted in the documentation, it's enabled by setting the xen-version
property on the KVM accelerator, e.g.:

 qemu-system-x86_64 -serial mon:stdio -M q35 -display none -m 1G -smp 2 \
    -accel kvm,xen-version=0x4000e,kernel-irqchip=split \
    -kernel vmlinuz-6.0.7-301.fc37.x86_64 \
    -append "console=ttyS0 root=/dev/sda1" \
    -drive file=/var/lib/libvirt/images/fedora28.qcow2,if=none,id=disk \
    -device ahci,id=ahci -device ide-hd,drive=disk,bus=ahci.0

Even before this was merged, we've already been using it to find and fix
bugs in the Linux kernel Xen guest support:

https://lore.kernel.org/all/4bffa69a949bfdc92c4a18e5a1c3cbb3b94a0d32.camel@infradead.org/
https://lore.kernel.org/all/871qnunycr.ffs@tglx/

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/hw/intc/i8259.h b/include/hw/intc/i8259.h
index a0e34dd990..c412575775 100644
--- a/include/hw/intc/i8259.h
+++ b/include/hw/intc/i8259.h
@@ -4,7 +4,15 @@
 /* i8259.c */
 
 extern PICCommonState *isa_pic;
-qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq);
+
+/*
+ * i8259_init()
+ *
+ * Create a i8259 device on an ISA @bus,
+ * connect its output to @parent_irq_in,
+ * return an (allocated) array of 16 input IRQs.
+ */
+qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq_in);
 qemu_irq *kvm_i8259_init(ISABus *bus);
 int pic_get_output(PICCommonState *s);
 int pic_read_irq(PICCommonState *s);