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5c9ca4ed89
When activating a gfn_to_pfn_cache, verify that the offset+length is sane
and usable before marking the cache active. Letting __kvm_gpc_refresh()
detect the problem results in a cache being marked active without setting
the GPA (or any other fields), which in turn results in KVM trying to
refresh a cache with INVALID_GPA.
Attempting to refresh a cache with INVALID_GPA isn't functionally
problematic, but it runs afoul of the sanity check that exactly one of
GPA or userspace HVA is valid, i.e. that a cache is either GPA-based or
HVA-based.
Reported-by: syzbot+106a4f72b0474e1d1b33@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/0000000000005fa5cc0613f1cebd@google.com
Fixes: 721f5b0dda ("KVM: pfncache: allow a cache to be activated with a fixed (userspace) HVA")
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Paul Durrant <paul@xen.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20240320001542.3203871-3-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.