mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-29 23:24:11 +08:00
1973cadd4c
MSR_F15H_PERF_CTL0-5, MSR_F15H_PERF_CTR0-5 MSRs are only available when X86_FEATURE_PERFCTR_CORE CPUID bit was exposed to the guest. KVM, however, allows these MSRs unconditionally because kvm_pmu_is_valid_msr() -> amd_msr_idx_to_pmc() check always passes and because kvm_pmu_set_msr() -> amd_pmu_set_msr() doesn't fail. In case of a counter (CTRn), no big harm is done as we only increase internal PMC's value but in case of an eventsel (CTLn), we go deep into perf internals with a non-existing counter. Note, kvm_get_msr_common() just returns '0' when these MSRs don't exist and this also seems to contradict architectural behavior which is #GP (I did check one old Opteron host) but changing this status quo is a bit scarier. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20210323084515.1346540-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.