Re: [PATCH v7 00/22] Support SDEI Virtualization

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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

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