[v2,0/6] LoongArch: Add pv ipi support on LoongArch VM

Message

bibo mao Jan. 8, 2024, 6:40 a.m. UTC

This patchset adds pv ipi support for VM. On physical machine, ipi HW
uses IOCSR registers, however there is trap into hypervisor when vcpu
accesses IOCSR registers if system is in VM mode. SWI is a interrupt
mechanism like SGI on ARM, software can send interrupt to CPU, only that
on LoongArch SWI can only be sent to local CPU now. So SWI can not used
for IPI on real HW system, however it can be used on VM when combined with
hypercall method. This patch uses SWI interrupt for IPI mechanism, SWI
injection uses hypercall method. And there is one trap with IPI sending,
however with SWI interrupt handler there is no trap.

This patch passes to runltp testcases, and unixbench score is 99% of
that on physical machine on 3C5000 single way machine. Here is unixbench
score with 16 cores on 3C5000 single way machine.

----------------UnixBench score on 3C5000 machine with 16 cores --------
Dhrystone 2 using register variables         116700.0  339749961.8  29113.1
Double-Precision Whetstone                       55.0      57716.9  10494.0
Execl Throughput                                 43.0      33563.4   7805.4
File Copy 1024 bufsize 2000 maxblocks          3960.0    1017912.5   2570.5
File Copy 256 bufsize 500 maxblocks            1655.0     260061.4   1571.4
File Copy 4096 bufsize 8000 maxblocks          5800.0    3216109.4   5545.0
Pipe Throughput                               12440.0   18404312.0  14794.5
Pipe-based Context Switching                   4000.0    3395856.2   8489.6
Process Creation                                126.0      55684.8   4419.4
Shell Scripts (1 concurrent)                     42.4      55901.8  13184.4
Shell Scripts (8 concurrent)                      6.0       7396.5  12327.5
System Call Overhead                          15000.0    6997351.4   4664.9
System Benchmarks Index Score                                        7288.6

----------------UnixBench score on VM with 16 cores -----------------
Dhrystone 2 using register variables         116700.0  341649555.5  29275.9
Double-Precision Whetstone                       55.0      57490.9  10452.9
Execl Throughput                                 43.0      33663.8   7828.8
File Copy 1024 bufsize 2000 maxblocks          3960.0    1047631.2   2645.5
File Copy 256 bufsize 500 maxblocks            1655.0     286671.0   1732.2
File Copy 4096 bufsize 8000 maxblocks          5800.0    3243588.2   5592.4
Pipe Throughput                               12440.0   16353087.8  13145.6
Pipe-based Context Switching                   4000.0    3100690.0   7751.7
Process Creation                                126.0      51502.1   4087.5
Shell Scripts (1 concurrent)                     42.4      56665.3  13364.4
Shell Scripts (8 concurrent)                      6.0       7412.1  12353.4
System Call Overhead                          15000.0    6962239.6   4641.5
System Benchmarks Index Score                                        7205.8

---
Change in V2:
  1. Add hw cpuid map support since ipi routing uses hw cpuid
  2. Refine changelog description
  3. Add hypercall statistic support for vcpu
  4. Set percpu pv ipi message buffer aligned with cacheline
  5. Refine pv ipi send logic, do not send ipi message with if there is
pending ipi message.
---

Bibo Mao (6):
  LoongArch: KVM: Add hypercall instruction emulation support
  LoongArch: KVM: Add cpucfg area for kvm hypervisor
  LoongArch/smp: Refine ipi ops on LoongArch platform
  LoongArch: Add paravirt interface for guest kernel
  LoongArch: KVM: Add physical cpuid map support
  LoongArch: Add pv ipi support on LoongArch system

 arch/loongarch/Kconfig                        |   9 +
 arch/loongarch/include/asm/Kbuild             |   1 -
 arch/loongarch/include/asm/hardirq.h          |   5 +
 arch/loongarch/include/asm/inst.h             |   1 +
 arch/loongarch/include/asm/irq.h              |  10 +-
 arch/loongarch/include/asm/kvm_host.h         |  27 +++
 arch/loongarch/include/asm/kvm_para.h         | 157 ++++++++++++++++++
 arch/loongarch/include/asm/kvm_vcpu.h         |   1 +
 arch/loongarch/include/asm/loongarch.h        |  10 ++
 arch/loongarch/include/asm/paravirt.h         |  27 +++
 .../include/asm/paravirt_api_clock.h          |   1 +
 arch/loongarch/include/asm/smp.h              |  31 ++--
 arch/loongarch/include/uapi/asm/Kbuild        |   2 -
 arch/loongarch/kernel/Makefile                |   1 +
 arch/loongarch/kernel/irq.c                   |  24 +--
 arch/loongarch/kernel/paravirt.c              | 151 +++++++++++++++++
 arch/loongarch/kernel/perf_event.c            |  14 +-
 arch/loongarch/kernel/setup.c                 |   2 +
 arch/loongarch/kernel/smp.c                   |  60 ++++---
 arch/loongarch/kernel/time.c                  |  12 +-
 arch/loongarch/kvm/exit.c                     | 122 ++++++++++++--
 arch/loongarch/kvm/vcpu.c                     |  62 ++++++-
 arch/loongarch/kvm/vm.c                       |  11 ++
 23 files changed, 639 insertions(+), 102 deletions(-)
 create mode 100644 arch/loongarch/include/asm/kvm_para.h
 create mode 100644 arch/loongarch/include/asm/paravirt.h
 create mode 100644 arch/loongarch/include/asm/paravirt_api_clock.h
 delete mode 100644 arch/loongarch/include/uapi/asm/Kbuild
 create mode 100644 arch/loongarch/kernel/paravirt.c


base-commit: 52b1853b080a082ec3749c3a9577f6c71b1d4a90