[PATCH 0/7] target/arm: Add vSPE support to KVM guest

[Haibo Xu]

This series add support for SPE(Statistical Profiling Extension)[1]
in KVM guest. It's based on Andrew Murray's kernel KVM patches V2[2],
and has been tested to ensure that guest can use SPE with valid data.
E.g.

In host:
$ ./qemu-system-aarch64 \
        -cpu host -M virt,accel=kvm,gic-version=3 -nographic -m 2048M \
        -kernel ./Image-new \
        -initrd /boot/initrd.img-5.6.0-rc2+ \
        -append "root=/dev/vda rw console=ttyAMA0" -nodefaults -serial stdio\
        -drive if=none,file=./xenial.rootfs.ext4,id=hd0,format=raw \
        -device virtio-blk-device,drive=hd0  \

In guest:
$ perf record -e arm_spe/ts_enable=1,pa_enable=1,pct_enable=1/ \
        dd if=/dev/zero of=/dev/null count=1000
$ perf report --dump-raw-trace > spe_buf.txt

The spe_buf.txt should contain similar data as below:

. ... ARM SPE data: size 135944 bytes
.  00000000:  b0 f4 d3 29 10 00 80 ff a0                      PC 
0xff80001029d3f4 el1 ns=1
.  00000009:  99 0b 00                                        LAT 11 ISSUE
.  0000000c:  98 0d 00                                        LAT 13 TOT
.  0000000f:  52 16 00                                        EV RETIRED 
L1D-ACCESS TLB-ACCESS
.  00000012:  49 00                                           LD
.  00000014:  b2 d0 40 d8 70 00 00 ff 00                      VA 
0xff000070d840d0
.  0000001d:  9a 01 00                                        LAT 1 XLAT
.  00000020:  00 00 00                                        PAD
.  00000023:  71 a5 1f b3 20 14 00 00 00                      TS 86447955877
.  0000002c:  b0 7c f9 29 10 00 80 ff a0                      PC 
0xff80001029f97c el1 ns=1
.  00000035:  99 02 00                                        LAT 2 ISSUE
.  00000038:  98 03 00                                        LAT 3 TOT
.  0000003b:  52 02 00                                        EV RETIRED
.  0000003e:  48 00                                           INSN-OTHER
.  00000040:  00 00 00                                        PAD
.  00000043:  71 ef 1f b3 20 14 00 00 00                      TS 86447955951
.  0000004c:  b0 f0 e9 29 10 00 80 ff a0                      PC 
0xff80001029e9f0 el1 ns=1
.  00000055:  99 02 00                                        LAT 2 ISSUE
.  00000058:  98 03 00                                        LAT 3 TOT
.  0000005b:  52 02 00                                        EV RETIRED

If you want to disable the vSPE support, you can use the 'spe=off' cpu
property:

./qemu-system-aarch64 \
        -cpu host,spe=off -M virt,accel=kvm,gic-version=3 -nographic -m 2048M \
        -kernel ./Image-new \
        -initrd /boot/initrd.img-5.6.0-rc2+ \
        -append "root=/dev/vda rw console=ttyAMA0" -nodefaults -serial stdio\
        -drive if=none,file=./xenial.rootfs.ext4,id=hd0,format=raw \
        -device virtio-blk-device,drive=hd0  \

Note:
(1) Since the kernel patches are still under review, some of the macros
    in the header files may be changed after merging. We may need to
    update them accordingly.
(2) These patches only add vSPE support in KVM mode, for TCG mode, I'm
    not sure whether we need to support it.
(3) Just followed the 'pmu' property, we only allow this feature to be
    removed from CPUs which enable it by default. But since the SPE is
    an optional feature extension for Armv8.2, I think a better way may
    be to disable it by default, and only enable it when the host cpu
    do have the feature.

[1]https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/
   posts/statistical-profiling-extension-for-armv8-a
[2]https://www.spinics.net/lists/arm-kernel/msg776228.html

Haibo Xu (7):
  update Linux headers with new vSPE macros
  target/arm/kvm: spe: Add helper to detect SPE when using KVM
  target/arm/cpu: spe: Add an option to turn on/off vSPE support
  target/arm/kvm: spe: Unify device attr operatioin helper
  target/arm/kvm: spe: Add device init and set_irq operations
  hw/arm/virt: spe: Add SPE fdt binding for virt machine
  target/arm/cpu: spe: Enable spe to work with host cpu

 hw/arm/virt-acpi-build.c      |  3 +++
 hw/arm/virt.c                 | 42 ++++++++++++++++++++++++++++++
 include/hw/acpi/acpi-defs.h   |  1 +
 include/hw/arm/virt.h         |  1 +
 linux-headers/asm-arm64/kvm.h |  4 +++
 linux-headers/linux/kvm.h     |  2 ++
 target/arm/cpu.c              | 34 +++++++++++++++++++++++++
 target/arm/cpu.h              |  5 ++++
 target/arm/kvm.c              | 11 ++++++++
 target/arm/kvm64.c            | 48 ++++++++++++++++++++++++++++++++---
 target/arm/kvm_arm.h          | 18 +++++++++++++
 11 files changed, 166 insertions(+), 3 deletions(-)

-- 
2.17.1