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5c8de4b3a5
Add a macro for use in kvm_set_cpu_caps() to automagically initialize features that KVM wants to support based solely on the CPU's capabilities, e.g. KVM advertises LA57 support if it's available in hardware, even if the host kernel isn't utilizing 57-bit virtual addresses. Track a features that are passed through to userspace (from hardware) in a local variable, and simply OR them in *after* adjusting the capabilities that came from boot_cpu_data. Note, eliminating the open-coded call to cpuid_ecx() also fixes a largely benign bug where KVM could incorrectly report LA57 support on Intel CPUs whose max supported CPUID is less than 7, i.e. if the max supported leaf (<7) happened to have bit 16 set. In practice, barring a funky virtual machine setup, the bug is benign as all known CPUs that support VMX also support leaf 7. Link: https://lore.kernel.org/r/20241128013424.4096668-30-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.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 reStructuredText 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.