KVM: x86: Adjust counter sample period after a wrmsr

mainline inclusion
from mainline-v5.6
commit 168d918f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5SDUS


CVE: NA

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The sample_period of a counter tracks when that counter will
overflow and set global status/trigger a PMI. However this currently
only gets set when the initial counter is created or when a counter is
resumed; this updates the sample period after a wrmsr so running
counters will accurately reflect their new value.

Signed-off-by: Eric Hankland <ehankland@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
[Yanan Wang: Adapt the code to linux v4.19]
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>