KVM: x86: Fix perfctr WRMSR for running counters

mainline inclusion
from mainline-v5.5
commit 4400cf54
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5SDUS


CVE: NA

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Correct the logic in intel_pmu_set_msr() for fixed and general purpose
counters. This was recently changed to set pmc->counter without taking
in to account the value of pmc_read_counter() which will be incorrect if
the counter is currently running and non-zero; this changes back to the
old logic which accounted for the value of currently running counters.

Signed-off-by: Eric Hankland <ehankland@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>