1. 26 Apr, 2013 1 commit
  2. 21 Jan, 2013 1 commit
  3. 06 Dec, 2012 1 commit
  4. 05 Oct, 2012 2 commits
  5. 08 Apr, 2012 4 commits
  6. 05 Mar, 2012 1 commit
    • Paul Mackerras's avatar
      KVM: PPC: Implement MMU notifiers for Book3S HV guests · 342d3db7
      Paul Mackerras authored
      This adds the infrastructure to enable us to page out pages underneath
      a Book3S HV guest, on processors that support virtualized partition
      memory, that is, POWER7.  Instead of pinning all the guest's pages,
      we now look in the host userspace Linux page tables to find the
      mapping for a given guest page.  Then, if the userspace Linux PTE
      gets invalidated, kvm_unmap_hva() gets called for that address, and
      we replace all the guest HPTEs that refer to that page with absent
      HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit
      set, which will cause an HDSI when the guest tries to access them.
      Finally, the page fault handler is extended to reinstantiate the
      guest HPTE when the guest tries to access a page which has been paged
      Since we can't intercept the guest DSI and ISI interrupts on PPC970,
      we still have to pin all the guest pages on PPC970.  We have a new flag,
      kvm->arch.using_mmu_notifiers, that indicates whether we can page
      guest pages out.  If it is not set, the MMU notifier callbacks do
      nothing and everything operates as before.
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
  7. 23 Jul, 2011 1 commit
    • Ohad Ben-Cohen's avatar
      virtio: expose for non-virtualization users too · e7254219
      Ohad Ben-Cohen authored
      virtio has been so far used only in the context of virtualization,
      and the virtio Kconfig was sourced directly by the relevant arch
      Kconfigs when VIRTUALIZATION was selected.
      Now that we start using virtio for inter-processor communications,
      we need to source the virtio Kconfig outside of the virtualization
      scope too.
      Moreover, some architectures might use virtio for both virtualization
      and inter-processor communications, so directly sourcing virtio
      might yield unexpected results due to conflicting selections.
      The simple solution offered by this patch is to always source virtio's
      Kconfig in drivers/Kconfig, and remove it from the appropriate arch
      Kconfigs. Additionally, a virtio menu entry has been added so virtio
      drivers don't show up in the general drivers menu.
      This way anyone can use virtio, though it's arguably less accessible
      (and neat!) for virtualization users now.
      Note: some architectures (mips and sh) seem to have a VIRTUALIZATION
      menu merely for sourcing virtio's Kconfig, so that menu is removed too.
      Signed-off-by: default avatarOhad Ben-Cohen <ohad@wizery.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
  8. 12 Jul, 2011 2 commits
    • Paul Mackerras's avatar
      KVM: PPC: book3s_hv: Add support for PPC970-family processors · 9e368f29
      Paul Mackerras authored
      This adds support for running KVM guests in supervisor mode on those
      PPC970 processors that have a usable hypervisor mode.  Unfortunately,
      Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to
      1), but the YDL PowerStation does have a usable hypervisor mode.
      There are several differences between the PPC970 and POWER7 in how
      guests are managed.  These differences are accommodated using the
      CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature
      bits.  Notably, on PPC970:
      * The LPCR, LPID or RMOR registers don't exist, and the functions of
        those registers are provided by bits in HID4 and one bit in HID0.
      * External interrupts can be directed to the hypervisor, but unlike
        POWER7 they are masked by MSR[EE] in non-hypervisor modes and use
        SRR0/1 not HSRR0/1.
      * There is no virtual RMA (VRMA) mode; the guest must use an RMO
        (real mode offset) area.
      * The TLB entries are not tagged with the LPID, so it is necessary to
        flush the whole TLB on partition switch.  Furthermore, when switching
        partitions we have to ensure that no other CPU is executing the tlbie
        or tlbsync instructions in either the old or the new partition,
        otherwise undefined behaviour can occur.
      * The PMU has 8 counters (PMC registers) rather than 6.
      * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist.
      * The SLB has 64 entries rather than 32.
      * There is no mediated external interrupt facility, so if we switch to
        a guest that has a virtual external interrupt pending but the guest
        has MSR[EE] = 0, we have to arrange to have an interrupt pending for
        it so that we can get control back once it re-enables interrupts.  We
        do that by sending ourselves an IPI with smp_send_reschedule after
        hard-disabling interrupts.
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
    • Paul Mackerras's avatar
      KVM: PPC: Add support for Book3S processors in hypervisor mode · de56a948
      Paul Mackerras authored
      This adds support for KVM running on 64-bit Book 3S processors,
      specifically POWER7, in hypervisor mode.  Using hypervisor mode means
      that the guest can use the processor's supervisor mode.  That means
      that the guest can execute privileged instructions and access privileged
      registers itself without trapping to the host.  This gives excellent
      performance, but does mean that KVM cannot emulate a processor
      architecture other than the one that the hardware implements.
      This code assumes that the guest is running paravirtualized using the
      PAPR (Power Architecture Platform Requirements) interface, which is the
      interface that IBM's PowerVM hypervisor uses.  That means that existing
      Linux distributions that run on IBM pSeries machines will also run
      under KVM without modification.  In order to communicate the PAPR
      hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code
      to include/linux/kvm.h.
      Currently the choice between book3s_hv support and book3s_pr support
      (i.e. the existing code, which runs the guest in user mode) has to be
      made at kernel configuration time, so a given kernel binary can only
      do one or the other.
      This new book3s_hv code doesn't support MMIO emulation at present.
      Since we are running paravirtualized guests, this isn't a serious
      With the guest running in supervisor mode, most exceptions go straight
      to the guest.  We will never get data or instruction storage or segment
      interrupts, alignment interrupts, decrementer interrupts, program
      interrupts, single-step interrupts, etc., coming to the hypervisor from
      the guest.  Therefore this introduces a new KVMTEST_NONHV macro for the
      exception entry path so that we don't have to do the KVM test on entry
      to those exception handlers.
      We do however get hypervisor decrementer, hypervisor data storage,
      hypervisor instruction storage, and hypervisor emulation assist
      interrupts, so we have to handle those.
      In hypervisor mode, real-mode accesses can access all of RAM, not just
      a limited amount.  Therefore we put all the guest state in the vcpu.arch
      and use the shadow_vcpu in the PACA only for temporary scratch space.
      We allocate the vcpu with kzalloc rather than vzalloc, and we don't use
      anything in the kvmppc_vcpu_book3s struct, so we don't allocate it.
      We don't have a shared page with the guest, but we still need a
      kvm_vcpu_arch_shared struct to store the values of various registers,
      so we include one in the vcpu_arch struct.
      The POWER7 processor has a restriction that all threads in a core have
      to be in the same partition.  MMU-on kernel code counts as a partition
      (partition 0), so we have to do a partition switch on every entry to and
      exit from the guest.  At present we require the host and guest to run
      in single-thread mode because of this hardware restriction.
      This code allocates a hashed page table for the guest and initializes
      it with HPTEs for the guest's Virtual Real Memory Area (VRMA).  We
      require that the guest memory is allocated using 16MB huge pages, in
      order to simplify the low-level memory management.  This also means that
      we can get away without tracking paging activity in the host for now,
      since huge pages can't be paged or swapped.
      This also adds a few new exports needed by the book3s_hv code.
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
  9. 17 May, 2010 3 commits
  10. 01 Mar, 2010 1 commit
  11. 25 Jan, 2010 1 commit
  12. 15 Jan, 2010 1 commit
    • Michael S. Tsirkin's avatar
      vhost_net: a kernel-level virtio server · 3a4d5c94
      Michael S. Tsirkin authored
      What it is: vhost net is a character device that can be used to reduce
      the number of system calls involved in virtio networking.
      Existing virtio net code is used in the guest without modification.
      There's similarity with vringfd, with some differences and reduced scope
      - uses eventfd for signalling
      - structures can be moved around in memory at any time (good for
        migration, bug work-arounds in userspace)
      - write logging is supported (good for migration)
      - support memory table and not just an offset (needed for kvm)
      common virtio related code has been put in a separate file vhost.c and
      can be made into a separate module if/when more backends appear.  I used
      Rusty's lguest.c as the source for developing this part : this supplied
      me with witty comments I wouldn't be able to write myself.
      What it is not: vhost net is not a bus, and not a generic new system
      call. No assumptions are made on how guest performs hypercalls.
      Userspace hypervisors are supported as well as kvm.
      How it works: Basically, we connect virtio frontend (configured by
      userspace) to a backend. The backend could be a network device, or a tap
      device.  Backend is also configured by userspace, including vlan/mac
      Status: This works for me, and I haven't see any crashes.
      Compared to userspace, people reported improved latency (as I save up to
      4 system calls per packet), as well as better bandwidth and CPU
      Features that I plan to look at in the future:
      - mergeable buffers
      - zero copy
      - scalability tuning: figure out the best threading model to use
      Note on RCU usage (this is also documented in vhost.h, near
      private_pointer which is the value protected by this variant of RCU):
      what is happening is that the rcu_dereference() is being used in a
      workqueue item.  The role of rcu_read_lock() is taken on by the start of
      execution of the workqueue item, of rcu_read_unlock() by the end of
      execution of the workqueue item, and of synchronize_rcu() by
      flush_workqueue()/flush_work(). In the future we might need to apply
      some gcc attribute or sparse annotation to the function passed to
      INIT_WORK(). Paul's ack below is for this RCU usage.
      (Includes fixes by Alan Cox <alan@linux.intel.com>,
      David L Stevens <dlstevens@us.ibm.com>,
      Chris Wright <chrisw@redhat.com>)
      Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
      Acked-by: default avatar"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  13. 05 Nov, 2009 1 commit
  14. 10 Sep, 2009 2 commits
  15. 24 Mar, 2009 2 commits
  16. 31 Dec, 2008 4 commits
  17. 15 Oct, 2008 1 commit
  18. 27 Apr, 2008 1 commit