From: David Woodhouse <dwmw2@infradead.org>
To: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Paul Durrant" <paul@xen.org>,
"Joao Martins" <joao.m.martins@oracle.com>,
"Ankur Arora" <ankur.a.arora@oracle.com>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>,
"Thomas Huth" <thuth@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Juan Quintela" <quintela@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
"Claudio Fontana" <cfontana@suse.de>,
"Julien Grall" <julien@xen.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
armbru@redhat.com
Subject: [PATCH v9 53/58] i386/xen: Document Xen HVM emulation
Date: Sat, 28 Jan 2023 08:11:08 +0000 [thread overview]
Message-ID: <20230128081113.1615111-54-dwmw2@infradead.org> (raw)
In-Reply-To: <20230128081113.1615111-1-dwmw2@infradead.org>
From: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: David Woodhouse <dwmw2@amazon.co.uk>
---
docs/system/i386/xen.rst | 50 +++++++++++++++++++++++++++++++++++++
docs/system/target-i386.rst | 1 +
2 files changed, 51 insertions(+)
create mode 100644 docs/system/i386/xen.rst
diff --git a/docs/system/i386/xen.rst b/docs/system/i386/xen.rst
new file mode 100644
index 0000000000..71506eb5c4
--- /dev/null
+++ b/docs/system/i386/xen.rst
@@ -0,0 +1,50 @@
+Xen HVM guest support
+=====================
+
+
+Description
+-----------
+
+KVM has support for hosting Xen guests, intercepting Xen hypercalls and event
+channel (Xen PV interrupt) delivery. This allows guests which expect to be
+run under Xen to be hosted in QEMU under Linux/KVM instead.
+
+Setup
+-----
+
+Xen mode is enabled by setting the ``xen-version`` property of the KVM
+accelerator to a 32-bit value in the ``XENVER_version`` form, with the Xen
+major version in the top 16 bits and the minor version in the low 16 bits,
+for example for Xen 4.10:
+
+.. parsed-literal::
+
+ |qemu_system| --accel kvm,xen-version=0x4000a
+
+Additionally, virtual APIC support can be advertised to the guest through the
+``xen-vapic`` CPU flag:
+
+.. parsed-literal::
+
+ |qemu_system| --accel kvm,xen-version=0x4000a --cpu host,+xen_vapic
+
+When Xen support is enabled, QEMU changes hypervisor identification (CPUID
+0x40000000..0x4000000A) to Xen. The KVM identification and features are not
+advertised to a Xen guest. If Hyper-V is also enabled, the Xen identification
+moves to leaves 0x40000100..0x4000010A.
+
+The Xen platform device is enabled automatically for a Xen guest. This allows
+a guest to unplug all emulated devices, in order to use Xen PV block and network
+drivers instead. Note that until the Xen PV device back ends are enabled to work
+with Xen mode in QEMU, that is unlikely to cause significant joy. Linux guests
+can be dissuaded from this by adding 'xen_emul_unplug=never' on their command
+line, and it can also be noted that AHCI disk controllers are exempt from being
+unplugged, as are passthrough VFIO PCI devices.
+
+OS requirements
+---------------
+
+The minimal Xen support in the KVM accelerator requires the host to be running
+Linux v5.12 or newer. Later versions add optimisations: Linux v5.17 added
+acceleration of interrupt delivery via the Xen PIRQ mechanism, and Linux v5.19
+accelerated Xen PV timers and inter-processor interrupts (IPIs).
diff --git a/docs/system/target-i386.rst b/docs/system/target-i386.rst
index e64c013077..77c2f3b979 100644
--- a/docs/system/target-i386.rst
+++ b/docs/system/target-i386.rst
@@ -27,6 +27,7 @@ Architectural features
i386/cpu
i386/hyperv
+ i386/xen
i386/kvm-pv
i386/sgx
i386/amd-memory-encryption
--
2.39.0
next prev parent reply other threads:[~2023-01-28 8:13 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-28 8:10 [PATCH v9 00/58] Xen HVM support under KVM David Woodhouse
2023-01-28 8:10 ` [PATCH v9 01/58] include: import Xen public headers to include/standard-headers/ David Woodhouse
2023-01-30 8:41 ` Thomas Huth
2023-01-31 8:26 ` David Woodhouse
2023-01-28 8:10 ` [PATCH v9 02/58] xen: add CONFIG_XEN_BUS and CONFIG_XEN_EMU options for Xen emulation David Woodhouse
2023-01-28 8:10 ` [PATCH v9 03/58] xen: Add XEN_DISABLED mode and make it default David Woodhouse
2023-01-28 8:10 ` [PATCH v9 04/58] i386/kvm: Add xen-version KVM accelerator property and init KVM Xen support David Woodhouse
2023-01-28 8:10 ` [PATCH v9 05/58] i386/kvm: handle Xen HVM cpuid leaves David Woodhouse
2023-01-28 8:10 ` [PATCH v9 06/58] i386/hvm: Set Xen vCPU ID in KVM David Woodhouse
2023-01-28 8:10 ` [PATCH v9 07/58] xen-platform: exclude vfio-pci from the PCI platform unplug David Woodhouse
2023-01-28 8:10 ` [PATCH v9 08/58] xen-platform: allow its creation with XEN_EMULATE mode David Woodhouse
2023-01-28 8:10 ` [PATCH v9 09/58] i386/xen: handle guest hypercalls David Woodhouse
2023-01-28 8:10 ` [PATCH v9 10/58] i386/xen: implement HYPERVISOR_xen_version David Woodhouse
2023-01-28 8:10 ` [PATCH v9 11/58] i386/xen: implement HYPERVISOR_sched_op, SCHEDOP_shutdown David Woodhouse
2023-01-28 8:10 ` [PATCH v9 12/58] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield David Woodhouse
2023-01-28 8:10 ` [PATCH v9 13/58] hw/xen: Add xen_overlay device for emulating shared xenheap pages David Woodhouse
2023-01-28 8:10 ` [PATCH v9 14/58] i386/xen: add pc_machine_kvm_type to initialize XEN_EMULATE mode David Woodhouse
2023-01-28 8:10 ` [PATCH v9 15/58] i386/xen: manage and save/restore Xen guest long_mode setting David Woodhouse
2023-01-28 8:10 ` [PATCH v9 16/58] i386/xen: implement HYPERVISOR_memory_op David Woodhouse
2023-01-28 8:10 ` [PATCH v9 17/58] i386/xen: implement XENMEM_add_to_physmap_batch David Woodhouse
2023-01-28 8:10 ` [PATCH v9 18/58] i386/xen: implement HYPERVISOR_hvm_op David Woodhouse
2023-01-28 8:10 ` [PATCH v9 19/58] i386/xen: implement HYPERVISOR_vcpu_op David Woodhouse
2023-01-28 8:10 ` [PATCH v9 20/58] i386/xen: handle VCPUOP_register_vcpu_info David Woodhouse
2023-01-28 8:10 ` [PATCH v9 21/58] i386/xen: handle VCPUOP_register_vcpu_time_info David Woodhouse
2023-01-28 8:10 ` [PATCH v9 22/58] i386/xen: handle VCPUOP_register_runstate_memory_area David Woodhouse
2023-01-28 8:10 ` [PATCH v9 23/58] i386/xen: implement HYPERVISOR_event_channel_op David Woodhouse
2023-01-28 8:10 ` [PATCH v9 24/58] i386/xen: implement HVMOP_set_evtchn_upcall_vector David Woodhouse
2023-01-28 8:10 ` [PATCH v9 25/58] i386/xen: implement HVMOP_set_param David Woodhouse
2023-01-28 8:10 ` [PATCH v9 26/58] hw/xen: Add xen_evtchn device for event channel emulation David Woodhouse
2023-01-28 8:10 ` [PATCH v9 27/58] i386/xen: Add support for Xen event channel delivery to vCPU David Woodhouse
2023-01-28 8:10 ` [PATCH v9 28/58] hw/xen: Implement EVTCHNOP_status David Woodhouse
2023-01-28 8:10 ` [PATCH v9 29/58] hw/xen: Implement EVTCHNOP_close David Woodhouse
2023-01-28 8:10 ` [PATCH v9 30/58] hw/xen: Implement EVTCHNOP_unmask David Woodhouse
2023-01-28 8:10 ` [PATCH v9 31/58] hw/xen: Implement EVTCHNOP_bind_virq David Woodhouse
2023-01-28 8:10 ` [PATCH v9 32/58] hw/xen: Implement EVTCHNOP_bind_ipi David Woodhouse
2023-01-28 8:10 ` [PATCH v9 33/58] hw/xen: Implement EVTCHNOP_send David Woodhouse
2023-01-28 8:10 ` [PATCH v9 34/58] hw/xen: Implement EVTCHNOP_alloc_unbound David Woodhouse
2023-01-28 8:10 ` [PATCH v9 35/58] hw/xen: Implement EVTCHNOP_bind_interdomain David Woodhouse
2023-01-28 8:10 ` [PATCH v9 36/58] hw/xen: Implement EVTCHNOP_bind_vcpu David Woodhouse
2023-01-28 8:10 ` [PATCH v9 37/58] hw/xen: Implement EVTCHNOP_reset David Woodhouse
2023-01-28 8:10 ` [PATCH v9 38/58] i386/xen: add monitor commands to test event injection David Woodhouse
2023-01-28 8:10 ` [PATCH v9 39/58] hw/xen: Support HVM_PARAM_CALLBACK_TYPE_GSI callback David Woodhouse
2023-01-28 8:10 ` [PATCH v9 40/58] hw/xen: Support HVM_PARAM_CALLBACK_TYPE_PCI_INTX callback David Woodhouse
2023-01-28 8:10 ` [PATCH v9 41/58] kvm/i386: Add xen-gnttab-max-frames property David Woodhouse
2023-01-28 8:10 ` [PATCH v9 42/58] hw/xen: Add xen_gnttab device for grant table emulation David Woodhouse
2023-01-28 8:10 ` [PATCH v9 43/58] hw/xen: Support mapping grant frames David Woodhouse
2023-01-28 8:10 ` [PATCH v9 44/58] i386/xen: Implement HYPERVISOR_grant_table_op and GNTTABOP_[gs]et_verson David Woodhouse
2023-01-28 8:11 ` [PATCH v9 45/58] hw/xen: Implement GNTTABOP_query_size David Woodhouse
2023-01-28 8:11 ` [PATCH v9 46/58] i386/xen: handle PV timer hypercalls David Woodhouse
2023-01-28 8:11 ` [PATCH v9 47/58] i386/xen: Reserve Xen special pages for console, xenstore rings David Woodhouse
2023-01-28 8:11 ` [PATCH v9 48/58] i386/xen: handle HVMOP_get_param David Woodhouse
2023-01-28 8:11 ` [PATCH v9 49/58] hw/xen: Add backend implementation of interdomain event channel support David Woodhouse
2023-01-28 8:11 ` [PATCH v9 50/58] hw/xen: Add xen_xenstore device for xenstore emulation David Woodhouse
2023-01-28 8:11 ` [PATCH v9 51/58] hw/xen: Add basic ring handling to xenstore David Woodhouse
2023-01-28 8:11 ` [PATCH v9 52/58] hw/xen: Automatically add xen-platform PCI device for emulated Xen guests David Woodhouse
2023-01-28 8:11 ` David Woodhouse [this message]
2023-01-28 8:11 ` [PATCH v9 54/58] i386/xen: Implement HYPERVISOR_physdev_op David Woodhouse
2023-01-28 8:11 ` [PATCH v9 55/58] hw/xen: Implement emulated PIRQ hypercall support David Woodhouse
2023-01-28 8:11 ` [PATCH v9 56/58] hw/xen: Support GSI mapping to PIRQ David Woodhouse
2023-01-28 8:11 ` [PATCH v9 57/58] hw/xen: Support MSI " David Woodhouse
2023-01-28 8:11 ` [PATCH v9 58/58] kvm/i386: Add xen-evtchn-max-pirq property David Woodhouse
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