• M. Vefa Bicakci's avatar
    xen/pv: Call get_cpu_address_sizes to set x86_virt/phys_bits · 405c018a
    M. Vefa Bicakci authored
    Commit d94a155c
    
     ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits
    adjustment corruption") has moved the query and calculation of the
    x86_virt_bits and x86_phys_bits fields of the cpuinfo_x86 struct
    from the get_cpu_cap function to a new function named
    get_cpu_address_sizes.
    
    One of the call sites related to Xen PV VMs was unfortunately missed
    in the aforementioned commit. This prevents successful boot-up of
    kernel versions 4.17 and up in Xen PV VMs if CONFIG_DEBUG_VIRTUAL
    is enabled, due to the following code path:
    
      enlighten_pv.c::xen_start_kernel
        mmu_pv.c::xen_reserve_special_pages
          page.h::__pa
            physaddr.c::__phys_addr
              physaddr.h::phys_addr_valid
    
    phys_addr_valid uses boot_cpu_data.x86_phys_bits to validate physical
    addresses. boot_cpu_data.x86_phys_bits is no longer populated before
    the call to xen_reserve_special_pages due to the aforementioned commit
    though, so the validation performed by phys_addr_valid fails, which
    causes __phys_addr to trigger a BUG, preventing boot-up.
    Signed-off-by: default avatarM. Vefa Bicakci <m.v.b@runbox.com>
    Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: Juergen Gross <jgross@suse.com>
    Cc: xen-devel@lists.xenproject.org
    Cc: x86@kernel.org
    Cc: stable@vger.kernel.org # for v4.17 and up
    Fixes: d94a155c
    
     ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption")
    Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
    405c018a
enlighten_pv.c 35.8 KB