1. 25 Jun, 2012 5 commits
    • Michael S. Tsirkin's avatar
      KVM: eoi msi documentation · c1af87dc
      Michael S. Tsirkin authored
      Document the new EOI MSR. Couldn't decide whether this change belongs
      conceptually on guest or host side, so a separate patch.
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      c1af87dc
    • Michael S. Tsirkin's avatar
      x86, bitops: note on __test_and_clear_bit atomicity · d0a69d63
      Michael S. Tsirkin authored
      __test_and_clear_bit is actually atomic with respect
      to the local CPU. Add a note saying that KVM on x86
      relies on this behaviour so people don't accidentaly break it.
      Also warn not to rely on this in portable code.
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      d0a69d63
    • Michael S. Tsirkin's avatar
      KVM guest: guest side for eoi avoidance · ab9cf499
      Michael S. Tsirkin authored
      The idea is simple: there's a bit, per APIC, in guest memory,
      that tells the guest that it does not need EOI.
      Guest tests it using a single est and clear operation - this is
      necessary so that host can detect interrupt nesting - and if set, it can
      skip the EOI MSR.
      
      I run a simple microbenchmark to show exit reduction
      (note: for testing, need to apply follow-up patch
      'kvm: host side for eoi optimization' + a qemu patch
       I posted separately, on host):
      
      Before:
      
      Performance counter stats for 'sleep 1s':
      
                  47,357 kvm:kvm_entry                                                [99.98%]
                       0 kvm:kvm_hypercall                                            [99.98%]
                       0 kvm:kvm_hv_hypercall                                         [99.98%]
                   5,001 kvm:kvm_pio                                                  [99.98%]
                       0 kvm:kvm_cpuid                                                [99.98%]
                  22,124 kvm:kvm_apic                                                 [99.98%]
                  49,849 kvm:kvm_exit                                                 [99.98%]
                  21,115 kvm:kvm_inj_virq                                             [99.98%]
                       0 kvm:kvm_inj_exception                                        [99.98%]
                       0 kvm:kvm_page_fault                                           [99.98%]
                  22,937 kvm:kvm_msr                                                  [99.98%]
                       0 kvm:kvm_cr                                                   [99.98%]
                       0 kvm:kvm_pic_set_irq                                          [99.98%]
                       0 kvm:kvm_apic_ipi                                             [99.98%]
                  22,207 kvm:kvm_apic_accept_irq                                      [99.98%]
                  22,421 kvm:kvm_eoi                                                  [99.98%]
                       0 kvm:kvm_pv_eoi                                               [99.99%]
                       0 kvm:kvm_nested_vmrun                                         [99.99%]
                       0 kvm:kvm_nested_intercepts                                    [99.99%]
                       0 kvm:kvm_nested_vmexit                                        [99.99%]
                       0 kvm:kvm_nested_vmexit_inject                                    [99.99%]
                       0 kvm:kvm_nested_intr_vmexit                                    [99.99%]
                       0 kvm:kvm_invlpga                                              [99.99%]
                       0 kvm:kvm_skinit                                               [99.99%]
                      57 kvm:kvm_emulate_insn                                         [99.99%]
                       0 kvm:vcpu_match_mmio                                          [99.99%]
                       0 kvm:kvm_userspace_exit                                       [99.99%]
                       2 kvm:kvm_set_irq                                              [99.99%]
                       2 kvm:kvm_ioapic_set_irq                                       [99.99%]
                  23,609 kvm:kvm_msi_set_irq                                          [99.99%]
                       1 kvm:kvm_ack_irq                                              [99.99%]
                     131 kvm:kvm_mmio                                                 [99.99%]
                     226 kvm:kvm_fpu                                                  [100.00%]
                       0 kvm:kvm_age_page                                             [100.00%]
                       0 kvm:kvm_try_async_get_page                                    [100.00%]
                       0 kvm:kvm_async_pf_doublefault                                    [100.00%]
                       0 kvm:kvm_async_pf_not_present                                    [100.00%]
                       0 kvm:kvm_async_pf_ready                                       [100.00%]
                       0 kvm:kvm_async_pf_completed
      
             1.002100578 seconds time elapsed
      
      After:
      
       Performance counter stats for 'sleep 1s':
      
                  28,354 kvm:kvm_entry                                                [99.98%]
                       0 kvm:kvm_hypercall                                            [99.98%]
                       0 kvm:kvm_hv_hypercall                                         [99.98%]
                   1,347 kvm:kvm_pio                                                  [99.98%]
                       0 kvm:kvm_cpuid                                                [99.98%]
                   1,931 kvm:kvm_apic                                                 [99.98%]
                  29,595 kvm:kvm_exit                                                 [99.98%]
                  24,884 kvm:kvm_inj_virq                                             [99.98%]
                       0 kvm:kvm_inj_exception                                        [99.98%]
                       0 kvm:kvm_page_fault                                           [99.98%]
                   1,986 kvm:kvm_msr                                                  [99.98%]
                       0 kvm:kvm_cr                                                   [99.98%]
                       0 kvm:kvm_pic_set_irq                                          [99.98%]
                       0 kvm:kvm_apic_ipi                                             [99.99%]
                  25,953 kvm:kvm_apic_accept_irq                                      [99.99%]
                  26,132 kvm:kvm_eoi                                                  [99.99%]
                  26,593 kvm:kvm_pv_eoi                                               [99.99%]
                       0 kvm:kvm_nested_vmrun                                         [99.99%]
                       0 kvm:kvm_nested_intercepts                                    [99.99%]
                       0 kvm:kvm_nested_vmexit                                        [99.99%]
                       0 kvm:kvm_nested_vmexit_inject                                    [99.99%]
                       0 kvm:kvm_nested_intr_vmexit                                    [99.99%]
                       0 kvm:kvm_invlpga                                              [99.99%]
                       0 kvm:kvm_skinit                                               [99.99%]
                     284 kvm:kvm_emulate_insn                                         [99.99%]
                      68 kvm:vcpu_match_mmio                                          [99.99%]
                      68 kvm:kvm_userspace_exit                                       [99.99%]
                       2 kvm:kvm_set_irq                                              [99.99%]
                       2 kvm:kvm_ioapic_set_irq                                       [99.99%]
                  28,288 kvm:kvm_msi_set_irq                                          [99.99%]
                       1 kvm:kvm_ack_irq                                              [99.99%]
                     131 kvm:kvm_mmio                                                 [100.00%]
                     588 kvm:kvm_fpu                                                  [100.00%]
                       0 kvm:kvm_age_page                                             [100.00%]
                       0 kvm:kvm_try_async_get_page                                    [100.00%]
                       0 kvm:kvm_async_pf_doublefault                                    [100.00%]
                       0 kvm:kvm_async_pf_not_present                                    [100.00%]
                       0 kvm:kvm_async_pf_ready                                       [100.00%]
                       0 kvm:kvm_async_pf_completed
      
             1.002039622 seconds time elapsed
      
      We see that # of exits is almost halved.
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      ab9cf499
    • Michael S. Tsirkin's avatar
      KVM: optimize ISR lookups · 8680b94b
      Michael S. Tsirkin authored
      We perform ISR lookups twice: during interrupt
      injection and on EOI. Typical workloads only have
      a single bit set there. So we can avoid ISR scans by
      1. counting bits as we set/clear them in ISR
      2. on set, caching the injected vector number
      3. on clear, invalidating the cache
      
      The real purpose of this is enabling PV EOI
      which needs to quickly validate the vector.
      But non PV guests also benefit: with this patch,
      and without interrupt nesting, apic_find_highest_isr
      will always return immediately without scanning ISR.
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      8680b94b
    • Michael S. Tsirkin's avatar
      KVM: document lapic regs field · 5eadf916
      Michael S. Tsirkin authored
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      5eadf916
  2. 19 Jun, 2012 1 commit
  3. 18 Jun, 2012 2 commits
  4. 13 Jun, 2012 4 commits
  5. 12 Jun, 2012 1 commit
  6. 06 Jun, 2012 4 commits
    • Avi Kivity's avatar
      Merge branch 'for-upstream' of git://github.com/agraf/linux-2.6 into next · 25e531a9
      Avi Kivity authored
      Alex says:
      
      "Changes this time include:
      
        - Generalize KVM_GUEST support to overall ePAPR code
        - Fix reset for Book3S HV
        - Fix machine check deferral when CONFIG_KVM_GUEST=y
        - Add support for BookE register DECAR"
      
      * 'for-upstream' of git://github.com/agraf/linux-2.6:
        KVM: PPC: Not optimizing MSR_CE and MSR_ME with paravirt.
        KVM: PPC: booke: Added DECAR support
        KVM: PPC: Book3S HV: Make the guest hash table size configurable
        KVM: PPC: Factor out guest epapr initialization
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      25e531a9
    • Michael S. Tsirkin's avatar
      KVM: disable uninitialized var warning · 79f702a6
      Michael S. Tsirkin authored
      I see this in 3.5-rc1:
      
      arch/x86/kvm/mmu.c: In function ‘kvm_test_age_rmapp’:
      arch/x86/kvm/mmu.c:1271: warning: ‘iter.desc’ may be used uninitialized in this function
      
      The line in question was introduced by commit
      1e3f42f0
      
       static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
                                    unsigned long data)
       {
      -       u64 *spte;
      +       u64 *sptep;
      +       struct rmap_iterator iter;   <- line 1271
              int young = 0;
      
              /*
      
      The reason I think is that the compiler assumes that
      the rmap value could be 0, so
      
      static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator
      *iter)
      {
              if (!rmap)
                      return NULL;
      
              if (!(rmap & 1)) {
                      iter->desc = NULL;
                      return (u64 *)rmap;
              }
      
              iter->desc = (struct pte_list_desc *)(rmap & ~1ul);
              iter->pos = 0;
              return iter->desc->sptes[iter->pos];
      }
      
      will not initialize iter.desc, but the compiler isn't
      smart enough to see that
      
              for (sptep = rmap_get_first(*rmapp, &iter); sptep;
                   sptep = rmap_get_next(&iter)) {
      
      will immediately exit in this case.
      I checked by adding
              if (!*rmapp)
                      goto out;
      on top which is clearly equivalent but disables the warning.
      
      This patch uses uninitialized_var to disable the warning without
      increasing code size.
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      79f702a6
    • Christoffer Dall's avatar
      KVM: Cleanup the kvm_print functions and introduce pr_XX wrappers · a737f256
      Christoffer Dall authored
      Introduces a couple of print functions, which are essentially wrappers
      around standard printk functions, with a KVM: prefix.
      
      Functions introduced or modified are:
       - kvm_err(fmt, ...)
       - kvm_info(fmt, ...)
       - kvm_debug(fmt, ...)
       - kvm_pr_unimpl(fmt, ...)
       - pr_unimpl(vcpu, fmt, ...) -> vcpu_unimpl(vcpu, fmt, ...)
      Signed-off-by: default avatarChristoffer Dall <c.dall@virtualopensystems.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      a737f256
    • Christian Borntraeger's avatar
      KVM: s390: Change maintainer · 4ae57b6c
      Christian Borntraeger authored
      Since Carsten is now working on a different project, Cornelia will
      work as the 2nd s390/kvm maintainer.
      Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      CC: Carsten Otte <cotte@de.ibm.com>
      CC: Cornelia Huck <cornelia.huck@de.ibm.com>
      Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      4ae57b6c
  7. 05 Jun, 2012 9 commits
  8. 04 Jun, 2012 12 commits
  9. 03 Jun, 2012 2 commits
    • Linus Torvalds's avatar
      vfs: move inode stat information closer together · 2f9d3df8
      Linus Torvalds authored
      The comment above it says "Stat data, not accessed from path walking",
      but in fact some of inode fields we use for the common stat data was way
      down at the end of the inode, causing unnecessary cache misses for the
      common stat operations.
      
      The inode structure is pretty big, and this can change padding depending
      on field width, but at least on the common 64-bit configurations this
      doesn't change the size.  Some of our inode layout has historically been
      to tro to avoid unnecessary padding fields, but cache locality is at
      least as important for layout, if not more.
      
      Noticed by looking at kernel profiles, and noticing that the "i_blkbits"
      access stood out like a sore thumb.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2f9d3df8
    • Linus Torvalds's avatar
      Linux 3.5-rc1 · f8f5701b
      Linus Torvalds authored
      f8f5701b