commit a16eb25b09c02a54c1c1b449d4b6cfa2cf3f013a upstream. Per the SDM, "When the local APIC handles a performance-monitoring counters interrupt, it automatically sets the mask flag in the LVT performance counter register." Add this behavior to KVM's local APIC emulation. Failure to mask the LVTPC entry results in spurious PMIs, e.g. when running Linux as a guest, PMI handlers that do a "late_ack" spew a large number of "dazed and confused" spurious NMI warnings. Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests") Cc: stable@vger.kernel.org Signed-off-by: Jim Mattson <jmattson@google.com> Tested-by: Mingwei Zhang <mizhang@google.com> Signed-off-by: Mingwei Zhang <mizhang@google.com> Link: https://lore.kernel.org/r/20230925173448.3518223-3-mizhang@google.com [sean: massage changelog, correct Fixes] Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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