1. Sep 10, 2018
  2. Sep 09, 2018
  3. Sep 03, 2018
  4. Sep 02, 2018
  5. Sep 01, 2018
  6. Aug 31, 2018
    • Joerg Roedel's avatar
      x86/efi: Load fixmap GDT in efi_call_phys_epilog() · eeb89e2b
      Joerg Roedel authored
      When PTI is enabled on x86-32 the kernel uses the GDT mapped in the fixmap
      for the simple reason that this address is also mapped for user-space.
      
      The efi_call_phys_prolog()/efi_call_phys_epilog() wrappers change the GDT
      to call EFI runtime services and switch back to the kernel GDT when they
      return. But the switch-back uses the writable GDT, not the fixmap GDT.
      
      When that happened and and the CPU returns to user-space it switches to the
      user %cr3 and tries to restore user segment registers. This fails because
      the writable GDT is not mapped in the user page-table, and without a GDT
      the fault handlers also can't be launched. The result is a triple fault and
      reboot of the machine.
      
      Fix that by restoring the GDT back to the fixmap GDT which is also mapped
      in the user page-table.
      
      Fixes: 7757d607
      
       x86/pti: ('Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32')
      Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: hpa@zytor.com
      Cc: linux-efi@vger.kernel.org
      Link: https://lkml.kernel.org/r/1535702738-10971-1-git-send-email-joro@8bytes.org
      eeb89e2b
    • Linus Torvalds's avatar
      Merge tag 'for-linus-4.19b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip · 4290d5b9
      Linus Torvalds authored
      Pull xen fixes from Juergen Gross:
      
       - minor cleanup avoiding a warning when building with new gcc
      
       - a patch to add a new sysfs node for Xen frontend/backend drivers to
         make it easier to obtain the state of a pv device
      
       - two fixes for 32-bit pv-guests to avoid intermediate L1TF vulnerable
         PTEs
      
      * tag 'for-linus-4.19b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
        x86/xen: remove redundant variable save_pud
        xen: export device state to sysfs
        x86/pae: use 64 bit atomic xchg function in native_ptep_get_and_clear
        x86/xen: don't write ptes directly in 32-bit PV guests
      4290d5b9