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[v2,00/12] target/arm: Add vSPE support to KVM guest

Message ID cover.1599549462.git.haibo.xu@linaro.org
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Series target/arm: Add vSPE support to KVM guest | expand

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Haibo Xu Sept. 8, 2020, 8:13 a.m. UTC 
v2:
  - Rebased on Andrew's patches[3]
  - Added compat codes to enable vSPE only for the 5.2 and 
    later machine types [Andrew]
  - Changed to use the ID register bit to identify the spe
    feature [Andrew/Richard]
  - Added the missing field in AcpiMadtGenericCpuInterface
    definition [Auger]
  - Split the un-tested userspace irqchip support for vSPE
    into a separate patch [Andrew]
  - Added doc and qtest for vSPE [Andrew]

Many thanks to Andrew, Richard, Philippe and Auger for their comments. 

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. To be specific, if you want to have a try
    on this patch series, you needs to replace on the kernel 5.5-rc2 based
    series, and do minor changes:

    -#define KVM_CAP_ARM_SPE_V1 179
    +#define KVM_CAP_ARM_SPE_V1 184

(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 'sve' property, we only allow this feature to be
    removed from CPUs which enable it by default when the host cpu support it.

[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
[3]https://www.mail-archive.com/qemu-devel@nongnu.org/msg727588.html

Haibo Xu (12):
  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: spe: Only enable SPE from 5.2 compat machines.
  target/arm/kvm: spe: Unify device attr operation helper
  target/arm/kvm: spe: Add device init and set_irq operations
  hw/arm/virt: Move post cpu realize check into its own function
  hw/arm/virt: Move kvm pmu setup to virt_cpu_post_init
  hw/arm/virt: spe: Add SPE fdt binding for virt machine
  target/arm/cpu: spe: Enable spe to work with host cpu
  target/arm/kvm: spe: Enable userspace irqchip support.
  target/arm: spe: Add corresponding doc and test.

 docs/system/arm/cpu-features.rst |  20 ++++++
 hw/arm/virt-acpi-build.c         |   3 +
 hw/arm/virt.c                    | 116 +++++++++++++++++++++++--------
 include/hw/acpi/acpi-defs.h      |   3 +
 include/hw/arm/virt.h            |   2 +
 linux-headers/asm-arm64/kvm.h    |   4 ++
 linux-headers/linux/kvm.h        |   2 +
 target/arm/cpu.c                 |  11 +++
 target/arm/cpu.h                 |  17 +++++
 target/arm/cpu64.c               |  57 +++++++++++++++
 target/arm/kvm.c                 |  10 +++
 target/arm/kvm64.c               |  56 +++++++++++++--
 target/arm/kvm_arm.h             |  18 +++++
 target/arm/monitor.c             |   2 +-
 tests/qtest/arm-cpu-features.c   |   9 +++
 15 files changed, 294 insertions(+), 36 deletions(-)

-- 
2.17.1