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This fixes two errors that prevent a guest using the HPT MMU from successfully migrating to a POWER9 host in radix MMU mode, or resizing its HPT when running on a radix host. The first bug was that commit8dc6cca556("KVM: PPC: Book3S HV: Don't rely on host's page size information", 2017-09-11) missed two uses of hpte_base_page_size(), one in the HPT rehashing code and one in kvm_htab_write() (which is used on the destination side in migrating a HPT guest). Instead we use kvmppc_hpte_base_page_shift(). Having the shift count means that we can use left and right shifts instead of multiplication and division in a few places. Along the way, this adds a check in kvm_htab_write() to ensure that the page size encoding in the incoming HPTEs is recognized, and if not return an EINVAL error to userspace. The second bug was that kvm_htab_write was performing some but not all of the functions of kvmhv_setup_mmu(), resulting in the destination VM being left in radix mode as far as the hardware is concerned. The simplest fix for now is make kvm_htab_write() call kvmppc_setup_partition_table() like kvmppc_hv_setup_htab_rma() does. In future it would be better to refactor the code more extensively to remove the duplication. Fixes:8dc6cca556("KVM: PPC: Book3S HV: Don't rely on host's page size information") Fixes:7a84084c60("KVM: PPC: Book3S HV: Set partition table rather than SDR1 on POWER9") Reported-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Tested-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.