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0c899c25d7
KVM special-cases writes to MSR_IA32_TSC so that all CPUs have the same base for the TSC. This logic is complicated, and we do not want it to have any effect once the VM is started. In particular, if any guest started to synchronize its TSCs with writes to MSR_IA32_TSC rather than MSR_IA32_TSC_ADJUST, the additional effect of kvm_write_tsc code would be uncharted territory. Therefore, this patch makes writes to MSR_IA32_TSC behave essentially the same as writes to MSR_IA32_TSC_ADJUST when they come from the guest. A new selftest (which passes both before and after the patch) checks the current semantics of writes to MSR_IA32_TSC and MSR_IA32_TSC_ADJUST originating from both the host and the guest. Upcoming work to remove the special side effects of host-initiated writes to MSR_IA32_TSC and MSR_IA32_TSC_ADJUST will be able to build onto this test, adjusting the host side to use the new APIs and achieve the same effect. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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.