If MSR access is rejected by MSR filtering, kvm_set_msr()/kvm_get_msr() would return KVM_MSR_RET_FILTERED, and the return value is only handled well for rdmsr/wrmsr. However, some instruction emulation and state transition also use kvm_set_msr()/kvm_get_msr() to do msr access but may trigger some unexpected results if MSR access is rejected, E.g. RDPID emulation would inject a #UD but RDPID wouldn't cause a exit when RDPID is supported in hardware and ENABLE_RDTSCP is set. And it would also cause failure when load MSR at nested entry/exit. Since msr filtering is based on MSR bitmap, it is better to only do MSR filtering for rdmsr/wrmsr. Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> Message-Id: <2b2774154f7532c96a6f04d71c82a8bec7d9e80b.1646655860.git.houwenlong.hwl@antgroup.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.
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