16f8553f75
commit a4443267800af240072280c44521caab61924e55 upstream. When apicv is disabled on a vCPU (e.g. by enabling KVM_CAP_HYPERV_SYNIC*), nothing happens to VMX MSRs on the already existing vCPUs, however, all new ones are created with PIN_BASED_POSTED_INTR filtered out. This is very confusing and results in the following picture inside the guest: $ rdmsr -ax 0x48d ff00000016 7f00000016 7f00000016 7f00000016 This is observed with QEMU and 4-vCPU guest: QEMU creates vCPU0, does KVM_CAP_HYPERV_SYNIC2 and then creates the remaining three. L1 hypervisor may only check CPU0's controls to find out what features are available and it will be very confused later. Switch to setting PIN_BASED_POSTED_INTR control based on global 'enable_apicv' setting. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.