Re: [PATCH v7 00/22] Support SDEI Virtualization
From: Gavin Shan
Date: Mon May 30 2022 - 02:58:02 EST
Hi Shijie,
On 5/30/22 2:47 PM, Shijie Huang wrote:
On 2022/5/27 16:02, Gavin Shan wrote:
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:
https://developer.arm.com/documentation/den0054/c
https://github.com/gwshan/linux ; ("kvm/arm64_sdei")
https://github.com/gwshan/qemu ; ("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 critial
events aren't supported by the implementation either. It means all events
are normal in terms of priority.
There are several objects (data structures) introduced to help on the
event registration, enablement, disablement, unregistration, reset,
delivery and handling.
* kvm_sdei_event_handler
SDEI event handler, which is provided through EVENT_REGISTER
hypercall, is called when the SDEI event is delivered from
host to guest.
* kvm_sdei_event_context
The saved (preempted) context when SDEI event is delivered
for handling.
* kvm_sdei_vcpu
SDEI events and their states.
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[18-19] Support SDEI migration
PATCH[20] Adds document about SDEI
PATCH[21-22] SDEI related selftest cases
The previous revisions can be found:
v6: https://lore.kernel.org/lkml/20220403153911.12332-4-gshan@xxxxxxxxxx/T/
v5: https://lore.kernel.org/kvmarm/20220322080710.51727-1-gshan@xxxxxxxxxx/
v4: https://lore.kernel.org/kvmarm/20210815001352.81927-1-gshan@xxxxxxxxxx/
v3: https://lore.kernel.org/kvmarm/20210507083124.43347-1-gshan@xxxxxxxxxx/
v2: https://lore.kernel.org/kvmarm/20210209032733.99996-1-gshan@xxxxxxxxxx/
v1: https://lore.kernel.org/kvmarm/20200817100531.83045-1-gshan@xxxxxxxxxx/
Testing
=======
[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
/home/gavin/sandbox/linux.main/tools/testing/selftests/kvm
[root@virtlab-arm01 kvm]# ./aarch64/sdei
NR_VCPUS: 2 SDEI Event: 0x00000000
--- VERSION
Version: 1.1 (vendor: 0x4b564d)
--- FEATURES
Shared event slots: 0
Private event slots: 0
Relative mode: No
--- PRIVATE_RESET
--- SHARED_RESET
--- PE_UNMASK
--- EVENT_GET_INFO
Type: Private
Priority: Normal
Signaled: Yes
--- EVENT_REGISTER
--- EVENT_ENABLE
--- EVENT_SIGNAL
Handled: Yes
IRQ: No
Status: Registered-Enabled-Running
PC/PSTATE: 000000000040232c 00000000600003c5
Regs: 0000000000000000 0000000000000000
0000000000000000 0000000000000000
--- PE_MASK
--- EVENT_DISABLE
--- EVENT_UNREGISTER
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.
https://github.com/gwshan/linux ; ("kvm/arm64_sdei")
https://github.com/gwshan/qemu ; ("kvm/arm64_sdei")
[2.1] Start the guests and migrate the source VM to the destination
VM.
[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
[guest-dst]#
=========== 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
I tested this patch set. It's okay.
Tested-by: Huang Shijie <shijie@xxxxxxxxxxxxxxxxxxxxxx>
[...]
Appreciate your efforts to test it through. I will have your
tested-by if respin is needed. Thank you for your time on this.
Thanks,
Gavin