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[ Upstream commit 8631ef59b62290c7d88e7209e35dfb47f33f4902 ] The SDM lists an architectural MSR IA32_CORE_CAPABILITIES (0xCF) that limits the theoretical maximum value of the Intel GP PMC MSRs allocated at 0xC1 to 14; likewise the Intel April 2022 SDM adds IA32_OVERCLOCKING_STATUS at 0x195 which limits the number of event selection MSRs to 15 (0x186-0x194). Limiting the maximum number of counters to 14 or 18 based on the currently allocated MSRs is clearly fragile, and it seems likely that Intel will even place PMCs 8-15 at a completely different range of MSR indices. So stop at the maximum number of GP PMCs supported today on Intel processors. There are some machines, like Intel P4 with non Architectural PMU, that may indeed have 18 counters, but those counters are in a completely different MSR address range and are not supported by KVM. Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: stable@vger.kernel.org Fixes: cf05a67b68b8 ("KVM: x86: omit "impossible" pmu MSRs from MSR list") Suggested-by: Jim Mattson <jmattson@google.com> Signed-off-by: Like Xu <likexu@tencent.com> Reviewed-by: Jim Mattson <jmattson@google.com> Message-Id: <20220919091008.60695-1-likexu@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.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.