1. 31 Jan, 2014 1 commit
    • Zoltan Kiss's avatar
      xen/grant-table: Avoid m2p_override during mapping · 08ece5bb
      Zoltan Kiss authored
      The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
      for blkback and future netback patches it just cause a lock contention, as
      those pages never go to userspace. Therefore this series does the following:
      - the original functions were renamed to __gnttab_[un]map_refs, with a new
        parameter m2p_override
      - based on m2p_override either they follow the original behaviour, or just set
        the private flag and call set_phys_to_machine
      - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
        m2p_override false
      - a new function gnttab_[un]map_refs_userspace provides the old behaviour
      
      It also removes a stray space from page.h and change ret to 0 if
      XENFEAT_auto_translated_physmap, as that is the only possible return value
      there.
      
      v2:
      - move the storing of the old mfn in page->index to gnttab_map_refs
      - move the function header update to a separate patch
      
      v3:
      - a new approach to retain old behaviour where it needed
      - squash the patches into one
      
      v4:
      - move out the common bits from m2p* functions, and pass pfn/mfn as parameter
      - clear page->private before doing anything with the page, so m2p_find_override
        won't race with this
      
      v5:
      - change return value handling in __gnttab_[un]map_refs
      - remove a stray space in page.h
      - add detail why ret = 0 now at some places
      
      v6:
      - don't pass pfn to m2p* functions, just get it locally
      Signed-off-by: default avatarZoltan Kiss <zoltan.kiss@citrix.com>
      Suggested-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      Acked-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      Acked-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      08ece5bb
  2. 30 Jan, 2014 3 commits
  3. 21 Jan, 2014 1 commit
    • Roger Pau Monne's avatar
      xen/pvh: Set X86_CR0_WP and others in CR0 (v2) · c9f6e997
      Roger Pau Monne authored
      otherwise we will get for some user-space applications
      that use 'clone' with CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID
      end up hitting an assert in glibc manifested by:
      
      general protection ip:7f80720d364c sp:7fff98fd8a80 error:0 in
      libc-2.13.so[7f807209e000+180000]
      
      This is due to the nature of said operations which sets and clears
      the PID.  "In the successful one I can see that the page table of
      the parent process has been updated successfully to use a
      different physical page, so the write of the tid on
      that page only affects the child...
      
      On the other hand, in the failed case, the write seems to happen before
      the copy of the original page is done, so both the parent and the child
      end up with the same value (because the parent copies the page after
      the write of the child tid has already happened)."
      (Roger's analysis). The nature of this is due to the Xen's commit
      of 51e2cac257ec8b4080d89f0855c498cbbd76a5e5
      "x86/pvh: set only minimal cr0 and cr4 flags in order to use paging"
      the CR0_WP was removed so COW features of the Linux kernel were not
      operating properly.
      
      While doing that also update the rest of the CR0 flags to be inline
      with what a baremetal Linux kernel would set them to.
      
      In 'secondary_startup_64' (baremetal Linux) sets:
      
      X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP |
      X86_CR0_AM | X86_CR0_PG
      
      The hypervisor for HVM type guests (which PVH is a bit) sets:
      X86_CR0_PE | X86_CR0_ET | X86_CR0_TS
      For PVH it specifically sets:
      X86_CR0_PG
      
      Which means we need to set the rest: X86_CR0_MP | X86_CR0_NE  |
      X86_CR0_WP | X86_CR0_AM to have full parity.
      Signed-off-by: default avatarRoger Pau Monne <roger.pau@citrix.com>
      Signed-off-by: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      [v1: Took out the cr4 writes to be a seperate patch]
      [v2: 0-DAY kernel found xen_setup_gdt to be missing a static]
      c9f6e997
  4. 20 Jan, 2014 1 commit
  5. 10 Jan, 2014 2 commits
  6. 07 Jan, 2014 6 commits
  7. 06 Jan, 2014 26 commits