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f48b4711dd
When guest transitions from/to long-mode by modifying MSR_EFER.LMA, the list of shared MSRs to be saved/restored on guest<->host transitions is updated (See vmx_set_efer() call to setup_msrs()). On every entry to guest, vcpu_enter_guest() calls vmx_prepare_switch_to_guest(). This function should also take care of setting the shared MSRs to be saved/restored. However, the function does nothing in case we are already running with loaded guest state (vmx->loaded_cpu_state != NULL). This means that even when guest modifies MSR_EFER.LMA which results in updating the list of shared MSRs, it isn't being taken into account by vmx_prepare_switch_to_guest() because it happens while we are running with loaded guest state. To fix above mentioned issue, add a flag to mark that the list of shared MSRs has been updated and modify vmx_prepare_switch_to_guest() to set shared MSRs when running with host state *OR* list of shared MSRs has been updated. Note that this issue was mistakenly introduced by commit678e315e78("KVM: vmx: add dedicated utility to access guest's kernel_gs_base") because previously vmx_set_efer() always called vmx_load_host_state() which resulted in vmx_prepare_switch_to_guest() to set shared MSRs. Fixes:678e315e78("KVM: vmx: add dedicated utility to access guest's kernel_gs_base") Reported-by: Eyal Moscovici <eyal.moscovici@oracle.com> Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com> Reviewed-by: Liam Merwick <liam.merwick@oracle.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Liran Alon <liran.alon@oracle.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.