KVM: arm/arm64: vgic-its: Introduce multiple LPI translation caches

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4J0W7


CVE: NA

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Because dist->lpi_list_lock is a perVM lock, when a virtual machine
is configured with multiple virtual NIC devices and receives
network packets at the same time, dist->lpi_list_lock will become
a performance bottleneck.

This patch increases the number of lpi_translation_cache to eight,
hashes the cpuid that executes irqfd_wakeup, and chooses which
lpi_translation_cache to use.

I tested the impact of virtual interrupt injection time-consuming：
Run the iperf command to send UDP packets to the VM:
    iperf -c $IP -u -b 40m -l 64 -t 6000&
The vm just receive UDP traffic. When configure multiple NICs,
each NIC receives the above iperf UDP traffic, This may reflect the
performance impact of shared resource competition, such as lock.

Observing the delay of virtual interrupt injection: the time spent
by the "irqfd_wakeup", "irqfd_inject" function, and kworker context
switch. The less the better.

ITS translation cache greatly reduces the delay of interrupt
injection compared to kworker thread, because it eliminate wakeup
and uncertain scheduling delay:
             kworker       ITS translation cache    improved
  1 NIC      6.692 us         1.766 us               73.6%
 10 NICs     7.536 us         2.574 us               65.8%

Increases the number of lpi_translation_cache reduce lock competition.
Multi-interrupt concurrent injections perform better:

            ITS translation cache    with patch      improved
   1 NIC        1.766 us              1.694 us         4.1%
 10 NICs        2.574 us              1.848 us        28.2%

Signed-off-by: Xiangyou Xie <xiexiangyou@huawei.com>
Reviewed-by: Hailiang Zhang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Chaochao Xing <xingchaochao@huawei.com>
Reviewed-by: Xiangyou Xie <xiexiangyou@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>