KVM: arm64: Record number of signal exits as a vCPU stat

mainline inclusion
from mainline-v5.14
commit fe5161d2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4VZJT
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe5161d2c39b8c2801f0e786631460c6e8a1cae4



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Most other architectures that implement KVM record a statistic
indicating the number of times a vCPU has exited due to a pending
signal. Add support for that stat to arm64.

Reviewed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210802192809.1851010-2-oupton@google.com



Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>