1. 30 9月, 2011 1 次提交
  2. 29 9月, 2011 1 次提交
    • S
      xen: modify kernel mappings corresponding to granted pages · 0930bba6
      Stefano Stabellini 提交于
      If we want to use granted pages for AIO, changing the mappings of a user
      vma and the corresponding p2m is not enough, we also need to update the
      kernel mappings accordingly.
      Currently this is only needed for pages that are created for user usages
      through /dev/xen/gntdev. As in, pages that have been in use by the
      kernel and use the P2M will not need this special mapping.
      However there are no guarantees that in the future the kernel won't
      start accessing pages through the 1:1 even for internal usage.
      
      In order to avoid the complexity of dealing with highmem, we allocated
      the pages lowmem.
      We issue a HYPERVISOR_grant_table_op right away in
      m2p_add_override and we remove the mappings using another
      HYPERVISOR_grant_table_op in m2p_remove_override.
      Considering that m2p_add_override and m2p_remove_override are called
      once per page we use multicalls and hypercall batching.
      
      Use the kmap_op pointer directly as argument to do the mapping as it is
      guaranteed to be present up until the unmapping is done.
      Before issuing any unmapping multicalls, we need to make sure that the
      mapping has already being done, because we need the kmap->handle to be
      set correctly.
      Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
      [v1: Removed GRANT_FRAME_BIT usage]
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      0930bba6
  3. 27 9月, 2011 2 次提交
  4. 24 9月, 2011 1 次提交
  5. 17 8月, 2011 1 次提交
    • J
      xen/x86: replace order-based range checking of M2P table by linear one · ccbcdf7c
      Jan Beulich 提交于
      The order-based approach is not only less efficient (requiring a shift
      and a compare, typical generated code looking like this
      
      	mov	eax, [machine_to_phys_order]
      	mov	ecx, eax
      	shr	ebx, cl
      	test	ebx, ebx
      	jnz	...
      
      whereas a direct check requires just a compare, like in
      
      	cmp	ebx, [machine_to_phys_nr]
      	jae	...
      
      ), but also slightly dangerous in the 32-on-64 case - the element
      address calculation can wrap if the next power of two boundary is
      sufficiently far away from the actual upper limit of the table, and
      hence can result in user space addresses being accessed (with it being
      unknown what may actually be mapped there).
      
      Additionally, the elimination of the mistaken use of fls() here (should
      have been __fls()) fixes a latent issue on x86-64 that would trigger
      if the code was run on a system with memory extending beyond the 44-bit
      boundary.
      
      CC: stable@kernel.org
      Signed-off-by: NJan Beulich <jbeulich@novell.com>
      [v1: Based on Jeremy's feedback]
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      ccbcdf7c
  6. 19 7月, 2011 1 次提交
  7. 12 7月, 2011 1 次提交
  8. 27 5月, 2011 1 次提交
    • D
      xen: cleancache shim to Xen Transcendent Memory · 5bc20fc5
      Dan Magenheimer 提交于
      This patch provides a shim between the kernel-internal cleancache
      API (see Documentation/mm/cleancache.txt) and the Xen Transcendent
      Memory ABI (see http://oss.oracle.com/projects/tmem).
      
      Xen tmem provides "hypervisor RAM" as an ephemeral page-oriented
      pseudo-RAM store for cleancache pages, shared cleancache pages,
      and frontswap pages.  Tmem provides enterprise-quality concurrency,
      full save/restore and live migration support, compression
      and deduplication.
      
      A presentation showing up to 8% faster performance and up to 52%
      reduction in sectors read on a kernel compile workload, despite
      aggressive in-kernel page reclamation ("self-ballooning") can be
      found at:
      
      http://oss.oracle.com/projects/tmem/dist/documentation/presentations/TranscendentMemoryXenSummit2010.pdfSigned-off-by: NDan Magenheimer <dan.magenheimer@oracle.com>
      Reviewed-by: NJeremy Fitzhardinge <jeremy@goop.org>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik Van Riel <riel@redhat.com>
      Cc: Jan Beulich <JBeulich@novell.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Andreas Dilger <adilger@sun.com>
      Cc: Ted Ts'o <tytso@mit.edu>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Cc: Joel Becker <joel.becker@oracle.com>
      Cc: Nitin Gupta <ngupta@vflare.org>
      5bc20fc5
  9. 19 5月, 2011 1 次提交
    • K
      xen/p2m/m2p/gnttab: Support GNTMAP_host_map in the M2P override. · d5431d52
      Konrad Rzeszutek Wilk 提交于
      We only supported the M2P (and P2M) override only for the
      GNTMAP_contains_pte type mappings. Meaning that we grants
      operations would "contain the machine address of the PTE to update"
      If the flag is unset, then the grant operation is
      "contains a host virtual address". The latter case means that
      the Hypervisor takes care of updating our page table
      (specifically the PTE entry) with the guest's MFN. As such we should
      not try to do anything with the PTE. Previous to this patch
      we would try to clear the PTE which resulted in Xen hypervisor
      being upset with us:
      
      (XEN) mm.c:1066:d0 Attempt to implicitly unmap a granted PTE c0100000ccc59067
      (XEN) domain_crash called from mm.c:1067
      (XEN) Domain 0 (vcpu#0) crashed on cpu#3:
      (XEN) ----[ Xen-4.0-110228  x86_64  debug=y  Not tainted ]----
      
      and crashing us.
      
      This patch allows us to inhibit the PTE clearing in the PV guest
      if the GNTMAP_contains_pte is not set.
      
      On the m2p_remove_override path we provide the same parameter.
      
      Sadly in the grant-table driver we do not have a mechanism to
      tell m2p_remove_override whether to clear the PTE or not. Since
      the grant-table driver is used by user-space, we can safely assume
      that it operates only on PTE's. Hence the implementation for
      it to work on !GNTMAP_contains_pte returns -EOPNOTSUPP. In the future
      we can implement the support for this. It will require some extra
      accounting structure to keep track of the page[i], and the flag.
      
      [v1: Added documentation details, made it return -EOPNOTSUPP instead
       of trying to do a half-way implementation]
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      d5431d52
  10. 18 4月, 2011 1 次提交
    • K
      xen/p2m/m2p/gnttab: Support GNTMAP_host_map in the M2P override. · cf8d9163
      Konrad Rzeszutek Wilk 提交于
      We only supported the M2P (and P2M) override only for the
      GNTMAP_contains_pte type mappings. Meaning that we grants
      operations would "contain the machine address of the PTE to update"
      If the flag is unset, then the grant operation is
      "contains a host virtual address". The latter case means that
      the Hypervisor takes care of updating our page table
      (specifically the PTE entry) with the guest's MFN. As such we should
      not try to do anything with the PTE. Previous to this patch
      we would try to clear the PTE which resulted in Xen hypervisor
      being upset with us:
      
      (XEN) mm.c:1066:d0 Attempt to implicitly unmap a granted PTE c0100000ccc59067
      (XEN) domain_crash called from mm.c:1067
      (XEN) Domain 0 (vcpu#0) crashed on cpu#3:
      (XEN) ----[ Xen-4.0-110228  x86_64  debug=y  Not tainted ]----
      
      and crashing us.
      
      This patch allows us to inhibit the PTE clearing in the PV guest
      if the GNTMAP_contains_pte is not set.
      
      On the m2p_remove_override path we provide the same parameter.
      
      Sadly in the grant-table driver we do not have a mechanism to
      tell m2p_remove_override whether to clear the PTE or not. Since
      the grant-table driver is used by user-space, we can safely assume
      that it operates only on PTE's. Hence the implementation for
      it to work on !GNTMAP_contains_pte returns -EOPNOTSUPP. In the future
      we can implement the support for this. It will require some extra
      accounting structure to keep track of the page[i], and the flag.
      
      [v1: Added documentation details, made it return -EOPNOTSUPP instead
       of trying to do a half-way implementation]
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      cf8d9163
  11. 14 4月, 2011 1 次提交
    • K
      xen/pci: Add xen_[find|register|unregister]_device_domain_owner functions. · c55fa78b
      Konrad Rzeszutek Wilk 提交于
      When the Xen PCI backend is told to enable or disable MSI/MSI-X functions,
      the initial domain performs these operations. The initial domain needs
      to know which domain (guest) is going to use the PCI device so when it
      makes the appropiate hypercall to retrieve the MSI/MSI-X vector it will
      also assign the PCI device to the appropiate domain (guest).
      
      This boils down to us needing a mechanism to find, set and unset the domain
      id that will be using the device.
      
      [v2: EXPORT_SYMBOL -> EXPORT_SYMBOL_GPL.]
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      c55fa78b
  12. 18 3月, 2011 1 次提交
  13. 14 3月, 2011 4 次提交
    • S
      xen/m2p: Check whether the MFN has IDENTITY_FRAME bit set.. · 706cc9d2
      Stefano Stabellini 提交于
      If there is no proper PFN value in the M2P for the MFN
      (so we get 0xFFFFF.. or 0x55555, or 0x0), we should
      consult the M2P override to see if there is an entry for this.
      [Note: we also consult the M2P override if the MFN
      is past our machine_to_phys size].
      
      We consult the P2M with the PFN. In case the returned
      MFN is one of the special values: 0xFFF.., 0x5555
      (which signify that the MFN can be either "missing" or it
      belongs to DOMID_IO) or the p2m(m2p(mfn)) != mfn, we check
      the M2P override. If we fail the M2P override check, we reset
      the PFN value to INVALID_P2M_ENTRY.
      
      Next we try to find the MFN in the P2M using the MFN
      value (not the PFN value) and if found, we know
      that this MFN is an identity value and return it as so.
      
      Otherwise we have exhausted all the posibilities and we
      return the PFN, which at this stage can either be a real
      PFN value found in the machine_to_phys.. array, or
      INVALID_P2M_ENTRY value.
      
      [v1: Added Review-by tag]
      Reviewed-by: NIan Campbell <ian.campbell@citrix.com>
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      706cc9d2
    • K
      xen/m2p: No need to catch exceptions when we know that there is no RAM · 146c4e51
      Konrad Rzeszutek Wilk 提交于
      .. beyound what we think is the end of memory. However there might
      be more System RAM - but assigned to a guest. Hence jump to the
      M2P override check and consult.
      
      [v1: Added Review-by tag]
      Reviewed-by: NIan Campbell <ian.campbell@citrix.com>
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      146c4e51
    • K
      xen/debugfs: Add 'p2m' file for printing out the P2M layout. · 2222e71b
      Konrad Rzeszutek Wilk 提交于
      We walk over the whole P2M tree and construct a simplified view of
      which PFN regions belong to what level and what type they are.
      
      Only enabled if CONFIG_XEN_DEBUG_FS is set.
      
      [v2: UNKN->UNKNOWN, use uninitialized_var]
      [v3: Rebased on top of mmu->p2m code split]
      [v4: Fixed the else if]
      Reviewed-by: NIan Campbell <Ian.Campbell@eu.citrix.com>
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      2222e71b
    • K
      xen/mmu: Add the notion of identity (1-1) mapping. · f4cec35b
      Konrad Rzeszutek Wilk 提交于
      Our P2M tree structure is a three-level. On the leaf nodes
      we set the Machine Frame Number (MFN) of the PFN. What this means
      is that when one does: pfn_to_mfn(pfn), which is used when creating
      PTE entries, you get the real MFN of the hardware. When Xen sets
      up a guest it initially populates a array which has descending
      (or ascending) MFN values, as so:
      
       idx: 0,  1,       2
       [0x290F, 0x290E, 0x290D, ..]
      
      so pfn_to_mfn(2)==0x290D. If you start, restart many guests that list
      starts looking quite random.
      
      We graft this structure on our P2M tree structure and stick in
      those MFN in the leafs. But for all other leaf entries, or for the top
      root, or middle one, for which there is a void entry, we assume it is
      "missing". So
       pfn_to_mfn(0xc0000)=INVALID_P2M_ENTRY.
      
      We add the possibility of setting 1-1 mappings on certain regions, so
      that:
       pfn_to_mfn(0xc0000)=0xc0000
      
      The benefit of this is, that we can assume for non-RAM regions (think
      PCI BARs, or ACPI spaces), we can create mappings easily b/c we
      get the PFN value to match the MFN.
      
      For this to work efficiently we introduce one new page p2m_identity and
      allocate (via reserved_brk) any other pages we need to cover the sides
      (1GB or 4MB boundary violations). All entries in p2m_identity are set to
      INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs,
      no other fancy value).
      
      On lookup we spot that the entry points to p2m_identity and return the identity
      value instead of dereferencing and returning INVALID_P2M_ENTRY. If the entry
      points to an allocated page, we just proceed as before and return the PFN.
      If the PFN has IDENTITY_FRAME_BIT set we unmask that in appropriate functions
      (pfn_to_mfn).
      
      The reason for having the IDENTITY_FRAME_BIT instead of just returning the
      PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
      non-identity pfn. To protect ourselves against we elect to set (and get) the
      IDENTITY_FRAME_BIT on all identity mapped PFNs.
      
      This simplistic diagram is used to explain the more subtle piece of code.
      There is also a digram of the P2M at the end that can help.
      Imagine your E820 looking as so:
      
                         1GB                                           2GB
      /-------------------+---------\/----\         /----------\    /---+-----\
      | System RAM        | Sys RAM ||ACPI|         | reserved |    | Sys RAM |
      \-------------------+---------/\----/         \----------/    \---+-----/
                                    ^- 1029MB                       ^- 2001MB
      
      [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100), 2048MB = 524288 (0x80000)]
      
      And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB
      is actually not present (would have to kick the balloon driver to put it in).
      
      When we are told to set the PFNs for identity mapping (see patch: "xen/setup:
      Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start
      of the PFN and the end PFN (263424 and 512256 respectively). The first step is
      to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page
      covers 512^2 of page estate (1GB) and in case the start or end PFN is not
      aligned on 512^2*PAGE_SIZE (1GB) we loop on aligned 1GB PFNs from start pfn to
      end pfn.  We reserve_brk top leaf pages if they are missing (means they point
      to p2m_mid_missing).
      
      With the E820 example above, 263424 is not 1GB aligned so we allocate a
      reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000.
      Each entry in the allocate page is "missing" (points to p2m_missing).
      
      Next stage is to determine if we need to do a more granular boundary check
      on the 4MB (or 2MB depending on architecture) off the start and end pfn's.
      We check if the start pfn and end pfn violate that boundary check, and if
      so reserve_brk a middle (p2m[x][y]) leaf page. This way we have a much finer
      granularity of setting which PFNs are missing and which ones are identity.
      In our example 263424 and 512256 both fail the check so we reserve_brk two
      pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing" values)
      and assign them to p2m[1][2] and p2m[1][488] respectively.
      
      At this point we would at minimum reserve_brk one page, but could be up to
      three. Each call to set_phys_range_identity has at maximum a three page
      cost. If we were to query the P2M at this stage, all those entries from
      start PFN through end PFN (so 1029MB -> 2001MB) would return INVALID_P2M_ENTRY
      ("missing").
      
      The next step is to walk from the start pfn to the end pfn setting
      the IDENTITY_FRAME_BIT on each PFN. This is done in 'set_phys_range_identity'.
      If we find that the middle leaf is pointing to p2m_missing we can swap it over
      to p2m_identity - this way covering 4MB (or 2MB) PFN space.  At this point we
      do not need to worry about boundary aligment (so no need to reserve_brk a middle
      page, figure out which PFNs are "missing" and which ones are identity), as that
      has been done earlier.  If we find that the middle leaf is not occupied by
      p2m_identity or p2m_missing, we dereference that page (which covers
      512 PFNs) and set the appropriate PFN with IDENTITY_FRAME_BIT. In our example
      263424 and 512256 end up there, and we set from p2m[1][2][256->511] and
      p2m[1][488][0->256] with IDENTITY_FRAME_BIT set.
      
      All other regions that are void (or not filled) either point to p2m_missing
      (considered missing) or have the default value of INVALID_P2M_ENTRY (also
      considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511]
      contain the INVALID_P2M_ENTRY value and are considered "missing."
      
      This is what the p2m ends up looking (for the E820 above) with this
      fabulous drawing:
      
         p2m         /--------------\
       /-----\       | &mfn_list[0],|                           /-----------------\
       |  0  |------>| &mfn_list[1],|    /---------------\      | ~0, ~0, ..      |
       |-----|       |  ..., ~0, ~0 |    | ~0, ~0, [x]---+----->| IDENTITY [@256] |
       |  1  |---\   \--------------/    | [p2m_identity]+\     | IDENTITY [@257] |
       |-----|    \                      | [p2m_identity]+\\    | ....            |
       |  2  |--\  \-------------------->|  ...          | \\   \----------------/
       |-----|   \                       \---------------/  \\
       |  3  |\   \                                          \\  p2m_identity
       |-----| \   \-------------------->/---------------\   /-----------------\
       | ..  +->+                        | [p2m_identity]+-->| ~0, ~0, ~0, ... |
       \-----/ /                         | [p2m_identity]+-->| ..., ~0         |
              / /---------------\        | ....          |   \-----------------/
             /  | IDENTITY[@0]  |      /-+-[x], ~0, ~0.. |
            /   | IDENTITY[@256]|<----/  \---------------/
           /    | ~0, ~0, ....  |
          |     \---------------/
          |
          p2m_missing             p2m_missing
      /------------------\     /------------\
      | [p2m_mid_missing]+---->| ~0, ~0, ~0 |
      | [p2m_mid_missing]+---->| ..., ~0    |
      \------------------/     \------------/
      
      where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT)
      Reviewed-by: NIan Campbell <ian.campbell@citrix.com>
      [v5: Changed code to use ranges, added ASCII art]
      [v6: Rebased on top of xen->p2m code split]
      [v4: Squished patches in just this one]
      [v7: Added RESERVE_BRK for potentially allocated pages]
      [v8: Fixed alignment problem]
      [v9: Changed 1<<3X to 1<<BITS_PER_LONG-X]
      [v10: Copied git commit description in the p2m code + Add Review tag]
      [v11: Title had '2-1' - should be '1-1' mapping]
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      f4cec35b
  14. 04 3月, 2011 1 次提交
    • K
      xen: Mark all initial reserved pages for the balloon as INVALID_P2M_ENTRY. · 6eaa412f
      Konrad Rzeszutek Wilk 提交于
      With this patch, we diligently set regions that will be used by the
      balloon driver to be INVALID_P2M_ENTRY and under the ownership
      of the balloon driver. We are OK using the __set_phys_to_machine
      as we do not expect to be allocating any P2M middle or entries pages.
      The set_phys_to_machine has the side-effect of potentially allocating
      new pages and we do not want that at this stage.
      
      We can do this because xen_build_mfn_list_list will have already
      allocated all such pages up to xen_max_p2m_pfn.
      
      We also move the check for auto translated physmap down the
      stack so it is present in __set_phys_to_machine.
      
      [v2: Rebased with mmu->p2m code split]
      Reviewed-by: NIan Campbell <ian.campbell@citrix.com>
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      6eaa412f
  15. 26 2月, 2011 2 次提交
  16. 19 2月, 2011 1 次提交
  17. 12 1月, 2011 2 次提交
  18. 07 1月, 2011 1 次提交
  19. 13 11月, 2010 1 次提交
  20. 23 10月, 2010 4 次提交
  21. 21 10月, 2010 2 次提交
  22. 18 10月, 2010 1 次提交
  23. 27 7月, 2010 1 次提交
  24. 23 7月, 2010 1 次提交
  25. 08 6月, 2010 1 次提交
  26. 05 11月, 2009 1 次提交
  27. 09 4月, 2009 1 次提交
  28. 31 3月, 2009 1 次提交
  29. 12 3月, 2009 1 次提交
  30. 02 3月, 2009 1 次提交
    • J
      xen: deal with virtually mapped percpu data · 9976b39b
      Jeremy Fitzhardinge 提交于
      The virtually mapped percpu space causes us two problems:
      
       - for hypercalls which take an mfn, we need to do a full pagetable
         walk to convert the percpu va into an mfn, and
      
       - when a hypercall requires a page to be mapped RO via all its aliases,
         we need to make sure its RO in both the percpu mapping and in the
         linear mapping
      
      This primarily affects the gdt and the vcpu info structure.
      Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      Cc: Xen-devel <xen-devel@lists.xensource.com>
      Cc: Gerd Hoffmann <kraxel@redhat.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Tejun Heo <htejun@gmail.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      9976b39b