Xen guests actually boot now. No PV drivers, as there's no grant table
or xenstore yet. But event channel IPIs are working, as are in-kernel
vCPU timers.
Moderately unhappy with having to poll for the GSI callback going down,
because we don't have a hook on the PIC EOI. If I can fix that for VFIO
while I'm at it, I may investigate further. I note that VFIO does seem
to use pci_device_route_intx_to_irq() and know the actual target GSI#,
which means that a trivial hook based on the GSI# might be feasible.
Next up, timers (which actually work with a new enough kernel where it's
all offloaded, but even then they need migration support). Then grant
tables, at which point it's time to work out how to provide a xenstore
implementation. I quite like the idea of that being purely internal,
but don't fancy adding *that* much code to qemu so will probably hook
up to an existing external xenstored.
Still need to fix up that platform PCI patch to call pam_update() to
change UMB mode.
qemu-system-x86_64 -serial mon:stdio -accel kvm,xen-version=0x4000a \
-device xen-platform -cpu host,+xen-vapic -display none \
-kernel /boot/vmlinuz-5.17.8-200.fc35.x86_64 \
-append "console=ttyS0,115200 earlyprintk=ttyS0,115200" \
--trace "kvm_xen*"
v3:
• Switch back to xen-version as KVM accelerator property, other review
feedback and bug fixes.
• Fix Hyper-V coexistence (ick, calling kvm_xen_init() again because
hyperv_enabled() doesn't return the right answer the first time).
• Implement event channel support, including GSI/PCI_INTX callback.
• Implement 32-bit guest support.
v2:
https://lore.kernel.org/qemu-devel/20221209095612.689243-1-dw...@infradead.org/
• Attempt to implement migration support; every Xen enlightenment is
now recorded either from vmstate_x86_cpu or from a new sysdev device
created for that purpose. And — I believe — correctly restored, in
the right order, on vmload.
• The shared_info page is created as a proper overlay instead of abusing
the underlying guest page. This is important because Windows doesn't
even select a GPA which had RAM behind it beforehand. This will be
extended to handle the grant frames too, in the fullness of time.
• Set vCPU attributes from the correct vCPU thread to avoid deadlocks.
• Carefully copy the entire hypercall argument structure from userspace
instead of assuming that it's contiguous in HVA space.
• Distinguish between "handled but intentionally returns -ENOSYS" and
"no idea what that was" in hypercalls, allowing us to emit a
GUEST_ERROR (actually, shouldn't that change to UNIMP?) on the
latter. Experience shows that to we'll end up having to intentionally
return -ENOSYS to a bunch of weird crap that ancient guests still
attempt to use, including XenServer local hacks that nobody even
remembers what they were (hvmop 0x101, anyone? Some old Windows
PV driver appears to be trying to use it...).
* Drop the '+xen' CPU property and present Xen CPUID instead of KVM
unconditionally when running in Xen mode. Make the Xen CPUID coexist
with Hyper-V CPUID as it should, though.
• Add XEN_EMU and XENFV_MACHINE (the latter to be XEN_EMU||XEN) config
options. Some more work on this, and the incestuous relationships
between the KVM target code and the 'platform' code, is going to be
required but it's probably better to get on with implementing the
real code so we can see those interactions in all their glory,
before losing too much sleep over the details here.
• Drop the GSI-2 hack, and also the patch which made the PCI platform
device have real RAM (which isn't needed now we have overlays, qv).
• Drop the XenState and XenVcpuState from KVMState and CPUArchState
respectively. The Xen-specific fields are natively included in
CPUArchState now though, for migration purposes. And we don't
keep a host pointer to the shared_info or vcpu_info at all any
more. With the kernel doing everything for us, we don't actually
need them.
v1:
https://lore.kernel.org/qemu-devel/20221205173137.607044-1-dw...@infradead.org/T/
v0: https://github.com/jpemartins/qemu/commits/xen-shim-rfc (Joao et al.)
Ankur Arora (2):
i386/xen: implement HVMOP_set_evtchn_upcall_vector
i386/xen: HVMOP_set_param / HVM_PARAM_CALLBACK_IRQ
David Woodhouse (20):
xen: add CONFIG_XENFV_MACHINE and CONFIG_XEN_EMU options for Xen emulation
xen: Add XEN_DISABLED mode and make it default
i386/kvm: Add xen-version machine property and init KVM Xen support
hw/xen: Add xen_overlay device for emulating shared xenheap pages
i386/xen: add pc_machine_kvm_type to initialize XEN_EMULATE mode
i386/xen: manage and save/restore Xen guest long_mode setting
i386/xen: implement XENMEM_add_to_physmap_batch
hw/xen: Implement EVTCHNOP_status
hw/xen: Implement EVTCHNOP_close
hw/xen: Implement EVTCHNOP_unmask
hw/xen: Implement EVTCHNOP_bind_virq
hw/xen: Implement EVTCHNOP_bind_ipi
hw/xen: Implement EVTCHNOP_send
hw/xen: Implement EVTCHNOP_alloc_unbound
hw/xen: Implement EVTCHNOP_bind_interdomain
hw/xen: Implement EVTCHNOP_bind_vcpu
hw/xen: Implement EVTCHNOP_reset
i386/xen: Implement SCHEDOP_poll
hw/xen: Support HVM_PARAM_CALLBACK_TYPE_GSI callback
hw/xen: Support HVM_PARAM_CALLBACK_TYPE_PCI_INTX callback
Joao Martins (16):
include: import xen public headers
i386/kvm: handle Xen HVM cpuid leaves
xen-platform: exclude vfio-pci from the PCI platform unplug
xen-platform: allow its creation with XEN_EMULATE mode
hw/xen_backend: refactor xen_be_init()
i386/xen: handle guest hypercalls
i386/xen: implement HYPERCALL_xen_version
i386/xen: implement HYPERVISOR_memory_op
i386/xen: implement HYPERVISOR_hvm_op
i386/xen: implement HYPERVISOR_vcpu_op
i386/xen: handle VCPUOP_register_vcpu_info
i386/xen: handle VCPUOP_register_vcpu_time_info
i386/xen: handle VCPUOP_register_runstate_memory_area
i386/xen: implement HYPERVISOR_event_channel_op
i386/xen: implement HYPERVISOR_sched_op
i386/xen: add monitor commands to test event injection
accel/kvm/kvm-all.c | 1 +
accel/xen/xen-all.c | 4 +
hmp-commands.hx | 30 +
hw/Kconfig | 1 +
hw/i386/Kconfig | 5 +
hw/i386/kvm/meson.build | 4 +
hw/i386/kvm/xen_evtchn.c | 1158 ++++++++++++++++++++
hw/i386/kvm/xen_evtchn.h | 41 +
hw/i386/kvm/xen_overlay.c | 261 +++++
hw/i386/kvm/xen_overlay.h | 18 +
hw/i386/pc.c | 19 +
hw/i386/xen/xen_platform.c | 29 +-
hw/xen/Kconfig | 3 +
hw/xen/xen-legacy-backend.c | 40 +-
include/hw/i386/pc.h | 3 +
include/hw/xen/xen-legacy-backend.h | 3 +
include/hw/xen/xen.h | 5 +-
include/standard-headers/xen/arch-x86/cpuid.h | 118 ++
include/standard-headers/xen/arch-x86/xen-x86_32.h | 194 ++++
include/standard-headers/xen/arch-x86/xen-x86_64.h | 241 ++++
include/standard-headers/xen/arch-x86/xen.h | 398 +++++++
include/standard-headers/xen/event_channel.h | 388 +++++++
include/standard-headers/xen/features.h | 143 +++
include/standard-headers/xen/grant_table.h | 686 ++++++++++++
include/standard-headers/xen/hvm/hvm_op.h | 395 +++++++
include/standard-headers/xen/hvm/params.h | 318 ++++++
include/standard-headers/xen/memory.h | 754 +++++++++++++
include/standard-headers/xen/physdev.h | 383 +++++++
include/standard-headers/xen/sched.h | 202 ++++
include/standard-headers/xen/trace.h | 341 ++++++
include/standard-headers/xen/vcpu.h | 248 +++++
include/standard-headers/xen/version.h | 113 ++
include/standard-headers/xen/xen-compat.h | 46 +
include/standard-headers/xen/xen.h | 1049 ++++++++++++++++++
include/sysemu/kvm_int.h | 1 +
include/sysemu/kvm_xen.h | 19 +
meson.build | 1 +
monitor/misc.c | 4 +
target/i386/cpu.c | 1 +
target/i386/cpu.h | 11 +
target/i386/kvm/kvm.c | 191 +++-
target/i386/kvm/meson.build | 2 +
target/i386/kvm/trace-events | 6 +
target/i386/kvm/xen-compat.h | 51 +
target/i386/kvm/xen-emu.c | 1034 +++++++++++++++++
target/i386/kvm/xen-emu.h | 32 +
target/i386/machine.c | 28 +
47 files changed, 8998 insertions(+), 25 deletions(-)
