Hey, Presented herewith a series that allows KVM to boot Xen x86 HVM guests (with their respective frontends and backends). On the hypervisor side, the approach is to keep the implementation similar to how HyperV was done on x86 KVM. On the backend driver side, the intent is to reuse Xen support. Note that this is an RFC so there are bugs and room for improvement. The intent is to get overall feedback before proceeding further. Running Xen guests on KVM, enables the following use-cases: * Run unmodified Xen HVM images; * Facilitate development/testing of Xen guests and Xen PV drivers; There has been a similar proposal in the past with Xenner, albeit this work has the following advantages over it: * Allows use of existing Xen PV drivers such as block, net etc, both as frontends and backends; * Xen tooling will see the same UABI as on Xen. This means things like xenstored, xenstore-list, xenstore-read run unmodified. Optionally, userspace VMM can emulate xenstore operations; This work is divided in two parts: 1. Xen HVM ABI support (patches 1 - 16) Support the necessary mechanisms to allow HVM guests to boot *without* PV frontends exposed to the guest. We start by intercepting hypercalls made by the guest, followed by event channel IPIs/VIRQs (for PV IPI, timers, spinlocks), pvclock and steal clock. Ankur Arora (1): KVM: x86/xen: support upcall vector Boris Ostrovsky (1): KVM: x86/xen: handle PV spinlocks slowpath Joao Martins (14): KVM: x86: fix Xen hypercall page msr handling KVM: x86/xen: intercept xen hypercalls if enabled KVM: x86/xen: register shared_info page KVM: x86/xen: setup pvclock updates KVM: x86/xen: update wallclock region KVM: x86/xen: register vcpu info KVM: x86/xen: register vcpu time info region KVM: x86/xen: register steal clock KVM: x86: declare Xen HVM guest capability KVM: x86/xen: evtchn signaling via eventfd KVM: x86/xen: store virq when assigning evtchn KVM: x86/xen: handle PV timers oneshot mode KVM: x86/xen: handle PV IPI vcpu yield KVM: x86: declare Xen HVM evtchn offload capability Documentation/virtual/kvm/api.txt | 23 ++ arch/x86/include/asm/kvm_host.h | 46 ++++ arch/x86/kvm/Makefile | 2 +- arch/x86/kvm/irq.c | 25 ++- arch/x86/kvm/irq_comm.c | 11 + arch/x86/kvm/trace.h | 33 +++ arch/x86/kvm/x86.c | 60 +++++- arch/x86/kvm/x86.h | 1 + arch/x86/kvm/xen.c | 1025 +++++++++++++++++++++++++++++ arch/x86/kvm/xen.h | 48 +++++ include/linux/kvm_host.h | 24 +++ include/uapi/linux/kvm.h | 73 ++++++- 12 files changed, 1361 insertions(+), 10 deletions(-) 2. PV Driver support (patches 17 - 39) We start by redirecting hypercalls from the backend to routines which emulate the behaviour that PV backends expect i.e. grant table and interdomain events. Next, we add support for late initialization of xenbus, followed by implementing frontend/backend communication mechanisms (i.e. grant tables and interdomain event channels). Finally, introduce xen-shim.ko, which will setup a limited Xen environment. This uses the added functionality of Xen specific shared memory (grant tables) and notifications (event channels). Note that patch 19 is useful to Xen on its own. Ankur Arora (11): x86/xen: export vcpu_info and shared_info x86/xen: make hypercall_page generic KVM: x86/xen: backend hypercall support KVM: x86/xen: grant map support KVM: x86/xen: grant unmap support KVM: x86/xen: interdomain evtchn support KVM: x86/xen: evtchn unmask support KVM: x86/xen: add additional evtchn ops xen-shim: introduce shim domain driver xen/gntdev: xen_shim_domain() support xen/xenbus: xen_shim_domain() support Joao Martins (12): xen/xenbus: xenbus uninit support xen-blkback: module_exit support KVM: x86/xen: domid allocation KVM: x86/xen: grant table init KVM: x86/xen: grant table grow support KVM: x86/xen: grant copy support xen/balloon: xen_shim_domain() support xen/grant-table: xen_shim_domain() support drivers/xen: xen_shim_domain() support xen-netback: xen_shim_domain() support xen-blkback: xen_shim_domain() support KVM: x86: declare Xen HVM Dom0 capability [See the entire series diffstat at the end] There are additional Qemu patches to take advantage of this (and they are available here[0][1]). An example on how you could run it would be: $ ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -serial mon:stdio \ -machine xenfv,accel=kvm \ -cpu host,-kvm,+xen,xen-major-version=4,xen-minor-version=4,+xen-vapic,+xen-pvclock \ -kernel /path/to/kernel -m 16G -smp 16,sockets=1,cores=16,threads=1,maxcpus=16 \ -append "earlyprintk=ttyS0 console=tty0 console=ttyS0" \ -device xen-platform -device usb-ehci -device usb-tablet,bus=usb-bus.0 -vnc :0 -k pt \ -netdev type=tap,id=net1,ifname=vif1.0,script=qemu-ifup \ -device xen-nic,netdev=net1,mac=52:54:00:12:34:56,backendtype=vif,backend=0 \ -drive file=/path/to/image.img,format=raw,id=legacy,if=ide \ -blockdev file,node-name=drive,filename=/path/to/image.img,locking=off \ -device xen-disk,vdev=xvda,drive=drive,backendtype=vbd Naturally other options are still at your disposal (e.g. booting with q35 platform, or with virtio, etc). Thoughts? Cheers, Joao [0] https://www.github.com/jpemartins/qemu xen-shim-rfc [1] https://www.github.com/jpemartins/linux xen-shim-rfc Documentation/virtual/kvm/api.txt | 33 + arch/x86/include/asm/kvm_host.h | 88 ++ arch/x86/include/asm/xen/hypercall.h | 12 +- arch/x86/kvm/Kconfig | 10 + arch/x86/kvm/Makefile | 3 +- arch/x86/kvm/irq.c | 25 +- arch/x86/kvm/irq_comm.c | 11 + arch/x86/kvm/trace.h | 33 + arch/x86/kvm/x86.c | 66 +- arch/x86/kvm/x86.h | 1 + arch/x86/kvm/xen-asm.S | 66 + arch/x86/kvm/xen-shim.c | 138 ++ arch/x86/kvm/xen.c | 2262 ++++++++++++++++++++++++++++++ arch/x86/kvm/xen.h | 55 + arch/x86/xen/enlighten.c | 49 + arch/x86/xen/enlighten_hvm.c | 3 +- arch/x86/xen/enlighten_pv.c | 1 + arch/x86/xen/enlighten_pvh.c | 3 +- arch/x86/xen/xen-asm_32.S | 2 +- arch/x86/xen/xen-asm_64.S | 2 +- arch/x86/xen/xen-head.S | 8 +- drivers/block/xen-blkback/blkback.c | 27 +- drivers/block/xen-blkback/common.h | 2 + drivers/block/xen-blkback/xenbus.c | 19 +- drivers/net/xen-netback/netback.c | 25 +- drivers/xen/balloon.c | 15 +- drivers/xen/events/events_2l.c | 4 +- drivers/xen/events/events_base.c | 6 +- drivers/xen/events/events_fifo.c | 2 +- drivers/xen/evtchn.c | 4 +- drivers/xen/features.c | 1 + drivers/xen/gntdev.c | 10 +- drivers/xen/grant-table.c | 15 +- drivers/xen/privcmd.c | 5 +- drivers/xen/xenbus/xenbus.h | 2 + drivers/xen/xenbus/xenbus_client.c | 28 +- drivers/xen/xenbus/xenbus_dev_backend.c | 4 +- drivers/xen/xenbus/xenbus_dev_frontend.c | 6 +- drivers/xen/xenbus/xenbus_probe.c | 57 +- drivers/xen/xenbus/xenbus_xs.c | 40 +- drivers/xen/xenfs/super.c | 7 +- drivers/xen/xenfs/xensyms.c | 4 + include/linux/kvm_host.h | 24 + include/uapi/linux/kvm.h | 104 +- include/xen/balloon.h | 7 + include/xen/xen-ops.h | 2 +- include/xen/xen.h | 5 + include/xen/xenbus.h | 3 + 48 files changed, 3232 insertions(+), 67 deletions(-) create mode 100644 arch/x86/kvm/xen-asm.S create mode 100644 arch/x86/kvm/xen-shim.c create mode 100644 arch/x86/kvm/xen.c create mode 100644 arch/x86/kvm/xen.h -- 2.11.0
