2bf934aadc
Disable the optimized APIC logical map if a logical ID covers multiple
MDAs, i.e. if a vCPU has multiple bits set in its ID. In logical mode,
events match if "ID & MDA != 0", i.e. creating an entry for only the
first bit can cause interrupts to be missed.
Note, creating an entry for every bit is also wrong as KVM would generate
IPIs for every matching bit. It would be possible to teach KVM to play
nice with this edge case, but it is very much an edge case and probably
not used in any real world OS, i.e. it's not worth optimizing.
Fixes: 1e08ec4a130e ("KVM: optimize apic interrupt delivery")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20230106011306.85230-21-seanjc@google.com>
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.