3d4a058945
[ Upstream commit df7e8818926eb4712b67421442acf7d568fe2645 ] Userspace that does not know about the AMD_IBRS bit might still allow the guest to protect itself with MSR_IA32_SPEC_CTRL using the Intel SPEC_CTRL bit. However, svm.c disallows this and will cause a #GP in the guest when writing to the MSR. Fix this by loosening the test and allowing the Intel CPUID bit, and in fact allow the AMD_STIBP bit as well since it allows writing to MSR_IA32_SPEC_CTRL too. Reported-by: Zhiyi Guo <zhguo@redhat.com> Analyzed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Analyzed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.