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Subject[PATCH v6 00/18] Support SDEI Virtualization
This series intends to virtualize Software Delegated Exception Interface
(SDEI), which is defined by DEN0054C (v1.1). It allows the hypervisor to
deliver NMI-alike SDEI event to guest and it's needed by Async PF to
deliver page-not-present notification from hypervisor to guest. The code
and the required qemu changes can be found from: ("kvm/arm64_sdei") ("kvm/arm64_sdei")

The design is quite strightforward by following the specification. The
(SDEI) events are classified into the shared and private ones according
to their scope. The shared event is system or VM scoped, but the private
event is vcpu scoped. This implementation doesn't support the shared
event because all the needed events are private. Besides, the migration
isn't supported by implementation and it's something to be supported
in future.

There are several objects (data structures) introduced to help on the
event registration, enablement, disablement, unregistration, reset,
delivery and handling.

* kvm_sdei_exposed_event
The event which are defined and exposed by KVM. The event can't
be registered until it's exposed. Besides, all the information
in this event can't be changed after it's exposed.

* kvm_sdei_event
The events are created based on the exposed events. Their states
are changed when hypercalls are received or they are delivered
to guest for handling.

* kvm_sdei_vcpu_context
The vcpu context helps to handle events. The interrupted context
is saved before the event handler is executed, and restored after
the event handler is to finish.

* kvm_sdei_vcpu
Place holder for all objects for one particular VCPU.

The patches are organized as below:

PATCH[01-02] Preparatory work to extend smccc_get_argx() and refactor
hypercall routing mechanism
PATCH[03] Adds SDEI virtualization infrastructure
PATCH[04-16] Supports various SDEI hypercalls and event handling
PATCH[17] Exposes SDEI capability
PATCH[18] Adds SDEI selftest case

The previous revisions can be found:


[1] The selftest case included in this series works fine. The default SDEI
event, whose number is zero, can be registered, enabled, raised. The
SDEI event handler can be invoked.

[host]# pwd
[root@virtlab-arm01 kvm]# ./aarch64/sdei

NR_VCPUS: 2 SDEI Event: 0x00000000

Version: 1.1 (vendor: 0x4b564d)
Shared event slots: 0
Private event slots: 0
Relative mode: No
Type: Private
Priority: Normal
Signaled: Yes
Handled: Yes
Status: Registered-Enabled-Running
PC/PSTATE: 000000000040232c 00000000600003c5
Regs: 0000000000000000 0000000000000000
0000000000000000 0000000000000000

Result: OK

[2] There are additional patches in the following repositories to create
procfs entries, allowing to inject SDEI event from host side. The
SDEI client in the guest side registers the SDEI default event, whose
number is zero. Also, the QEMU exports SDEI ACPI table and supports
migration for SDEI. ("kvm/arm64_sdei") ("kvm/arm64_sdei")

[2.1] Start the guests and migrate the source VM to the destination

[host]# /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
-accel kvm -machine virt,gic-version=host \
-cpu host -smp 6,sockets=2,cores=3,threads=1 \
-m 1024M,slots=16,maxmem=64G \
: \
-kernel /home/gavin/sandbox/linux.guest/arch/arm64/boot/Image \
-initrd /home/gavin/sandbox/images/rootfs.cpio.xz \
-append earlycon=pl011,mmio,0x9000000 \

[host]# /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
-accel kvm -machine virt,gic-version=host \
-cpu host -smp 6,sockets=2,cores=3,threads=1 \
-m 1024M,slots=16,maxmem=64G \
: \
-kernel /home/gavin/sandbox/linux.guest/arch/arm64/boot/Image \
-initrd /home/gavin/sandbox/images/rootfs.cpio.xz \
-append earlycon=pl011,mmio,0x9000000 \
-incoming tcp:0:4444 \

[2.2] Check kernel log on the source VM. The SDEI service is enabled
and the default SDEI event (0x0) is enabled.

[guest-src]# dmesg | grep -i sdei
ACPI: SDEI 0x000000005BC80000 000024 \
(v00 BOCHS BXPC 00000001 BXPC 00000001)
sdei: SDEIv1.1 (0x4b564d) detected in firmware.
SDEI TEST: Version 1.1, Vendor 0x4b564d
sdei_init: SDEI event (0x0) registered
sdei_init: SDEI event (0x0) enabled

(qemu) migrate -d tcp:localhost:4444

[2.3] Migrate the source VM to the destination VM. Inject SDEI event
to the destination VM. The event is raised and handled.

(qemu) migrate -d tcp:localhost:4444

[host]# echo 0 > /proc/kvm/kvm-5360/vcpu-1

=========== SDEI Event (CPU#1) ===========
Event: 0000000000000000 Parameter: 00000000dabfdabf
PC: ffff800008cbb554 PSTATE: 00000000604000c5 SP: ffff800009c7bde0
Regs: 00000000000016ee ffff00001ffd2e28 00000000000016ed 0000000000000001
ffff800016c28000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 ffff800009399008
ffff8000097d9af0 ffff8000097d99f8 ffff8000093a8db8 ffff8000097d9b18
0000000000000000 0000000000000000 ffff000000339d00 0000000000000000
0000000000000000 ffff800009c7bde0 ffff800008cbb5c4
Context: 00000000000016ee ffff00001ffd2e28 00000000000016ed 0000000000000001
ffff800016c28000 03ffffffffffffff 000000024325db59 ffff8000097de190
ffff00000033a790 ffff800008cbb814 0000000000000a30 0000000000000000

* Rebased to v5.18.rc1 (Gavin)
* Pass additional argument to smccc_get_arg() (Oliver)
* Add preparatory patch to route hypercalls based on their
owners (Oliver)
* Remove the support for shared event. (Oliver/Gavin)
* Remove the support for migration and add-on patches to
support it in future (Oliver)
* The events are exposed by KVM instead of VMM (Oliver)
* kvm_sdei_state.h is dropped and all the structures are
folded into the corresponding ones in kvm_sdei.h (Oliver)
* Rename 'struct kvm_sdei_registered_event' to
'struct kvm_sdei_event' (Oliver)
* Misc comments from Oliver Upon (Oliver)
* Rebased to v5.17.rc7 (Gavin)
* Unified names for the objects, data structures, variables
and functions. The events have been named as exposed,
registered and vcpu event. The staes needs to be migrated
is put into kvm_sdei_state.h (Eric)
* More inline functions to visit SDEI event's properties (Eric)
* Support unregistration pending state (Eric)
* Support v1.1 SDEI specification (Eric)
* Fold the code to inject, deliver and handle SDEI event
from PATCH[v4 13/18/19] into PATCH[v5 13] (Eric)
* Simplified ioctl interface to visit all events at once (Eric/Gavin)
* Improved reference count and avoid its migration. Also,
the limit to memory allocation is added based on it. (Eric)
* Change the return values from hypercall functions (Eric)
* Validate @ksdei and @vsdi in kvm_sdei_hypercall() (Shannon)
* Add document to explain how SDEI virtualization and the
migration are supported (Eric)
* Improved selftest case to inject and handle SDEI event (Gavin)
* Improved comments and commit logs (Eric)
* Address misc comments from Eric. Hopefully, all of them
are covered in v5 because Eric provided lots of comments
in the last round of review (Eric)
* Rebased to v5.14.rc5 (Gavin)
* Rebased to v5.13.rc1 (Gavin)
* Use linux data types in kvm_sdei.h (Gavin)
* Rebased to v5.11.rc6 (Gavin)
* Dropped changes related to SDEI client driver (Gavin)
* Removed support for passthrou SDEI events (Gavin)
* Redesigned data structures (Gavin)
* Implementation is almost rewritten as the data
structures are totally changed (Gavin)
* Added ioctl commands to support migration (Gavin)

Gavin Shan (18):
KVM: arm64: Extend smccc_get_argx()
KVM: arm64: Route hypercalls based on their owner
KVM: arm64: Add SDEI virtualization infrastructure
KVM: arm64: Support SDEI_EVENT_REGISTER hypercall
KVM: arm64: Support SDEI_EVENT_CONTEXT hypercall
KVM: arm64: Support SDEI_EVENT_UNREGISTER hypercall
KVM: arm64: Support SDEI_EVENT_STATUS hypercall
KVM: arm64: Support SDEI_EVENT_GET_INFO hypercall
KVM: arm64: Support SDEI_PE_{MASK, UNMASK} hypercall
KVM: arm64: Support SDEI event injection, delivery
KVM: arm64: Support SDEI_EVENT_SIGNAL hypercall
KVM: arm64: Support SDEI_FEATURES hypercall
KVM: arm64: Support SDEI_VERSION hypercall
KVM: arm64: Expose SDEI capability
KVM: selftests: Add SDEI test case

Documentation/virt/kvm/api.rst | 11 +
arch/arm64/include/asm/kvm_emulate.h | 1 +
arch/arm64/include/asm/kvm_host.h | 3 +
arch/arm64/include/asm/kvm_sdei.h | 155 ++++
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/arm.c | 8 +
arch/arm64/kvm/hyp/exception.c | 7 +
arch/arm64/kvm/hypercalls.c | 204 +++--
arch/arm64/kvm/inject_fault.c | 29 +
arch/arm64/kvm/psci.c | 14 +-
arch/arm64/kvm/pvtime.c | 2 +-
arch/arm64/kvm/sdei.c | 902 +++++++++++++++++++++
arch/arm64/kvm/trng.c | 4 +-
include/kvm/arm_hypercalls.h | 19 +-
include/uapi/linux/arm_sdei.h | 4 +
include/uapi/linux/kvm.h | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
tools/testing/selftests/kvm/aarch64/sdei.c | 498 ++++++++++++
18 files changed, 1767 insertions(+), 98 deletions(-)
create mode 100644 arch/arm64/include/asm/kvm_sdei.h
create mode 100644 arch/arm64/kvm/sdei.c
create mode 100644 tools/testing/selftests/kvm/aarch64/sdei.c


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