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2e2409afe5
Currently, CLFLUSH is used to flush SEV guest memory before the guest is terminated (or a memory hotplug region is removed). However, CLFLUSH is not enough to ensure that SEV guest tagged data is flushed from the cache. With33af3a7ef9("KVM: SVM: Reduce WBINVD/DF_FLUSH invocations"), the original WBINVD was removed. This then exposed crashes at random times because of a cache flush race with a page that had both a hypervisor and a guest tag in the cache. Restore the WBINVD when destroying an SEV guest and add a WBINVD to the svm_unregister_enc_region() function to ensure hotplug memory is flushed when removed. The DF_FLUSH can still be avoided at this point. Fixes:33af3a7ef9("KVM: SVM: Reduce WBINVD/DF_FLUSH invocations") Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Message-Id: <c8bf9087ca3711c5770bdeaafa3e45b717dc5ef4.1584720426.git.thomas.lendacky@amd.com> Cc: stable@vger.kernel.org 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.