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2016-03-08KVM: MMU: simplify last_pte_bitmapPaolo Bonzini1-24/+26
Branch-free code is fun and everybody knows how much Avi loves it, but last_pte_bitmap takes it a bit to the extreme. Since the code is simply doing a range check, like (level == 1 || ((gpte & PT_PAGE_SIZE_MASK) && level < N) we can make it branch-free without storing the entire truth table; it is enough to cache N. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: coalesce more page zapping in mmu_sync_childrenPaolo Bonzini1-4/+11
mmu_sync_children can only process up to 16 pages at a time. Check if we need to reschedule, and do not bother zapping the pages until that happens. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: move zap/flush to kvm_mmu_get_pagePaolo Bonzini1-20/+20
kvm_mmu_get_page is the only caller of kvm_sync_page_transient and kvm_sync_pages. Moving the handling of the invalid_list there removes the need for the underdocumented kvm_sync_page_transient function. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: invert return value of mmu.sync_page and *kvm_sync_page*Paolo Bonzini2-19/+16
Return true if the page was synced (and the TLB must be flushed) and false if the page was zapped. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: cleanup __kvm_sync_page and its callersPaolo Bonzini1-6/+4
Calling kvm_unlink_unsync_page in the middle of __kvm_sync_page makes things unnecessarily tricky. If kvm_mmu_prepare_zap_page is called, it will call kvm_unlink_unsync_page too. So kvm_unlink_unsync_page can be called just as well at the beginning or the end of __kvm_sync_page... which means that we might do it in kvm_sync_page too and remove the parameter. kvm_sync_page ends up being the same code that kvm_sync_pages used to have before the previous patch. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: use kvm_sync_page in kvm_sync_pagesPaolo Bonzini1-2/+1
If the last argument is true, kvm_unlink_unsync_page is called anyway in __kvm_sync_page (either by kvm_mmu_prepare_zap_page or by __kvm_sync_page itself). Therefore, kvm_sync_pages can just call kvm_sync_page, instead of going through kvm_unlink_unsync_page+__kvm_sync_page. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: move TLB flush out of __kvm_sync_pagePaolo Bonzini1-29/+24
By doing this, kvm_sync_pages can use __kvm_sync_page instead of reinventing it. Because of kvm_mmu_flush_or_zap, the code does not end up being more complex than before, and more cleanups to kvm_sync_pages will come in the next patches. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: introduce kvm_mmu_flush_or_zapPaolo Bonzini1-9/+10
This is a generalization of mmu_pte_write_flush_tlb, that also takes care of calling kvm_mmu_commit_zap_page. The next patches will introduce more uses. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: drop local copy of mul_u64_u32_divPaolo Bonzini1-23/+3
A function that does the same as i8254.c's muldiv64 has been added (for KVM's own use, in fact!) in include/linux/math64.h. Use it instead of muldiv64. Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: MMU: check kvm_mmu_pages and mmu_page_path indicesXiao Guangrong1-1/+6
Give a special invalid index to the root of the walk, so that we can check the consistency of kvm_mmu_pages and mmu_page_path. Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Extracted from a bigger patch proposed by Guangrong. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: MMU: Fix ubsan warningsPaolo Bonzini1-24/+33
kvm_mmu_pages_init is doing some really yucky stuff. It is setting up a sentinel for mmu_page_clear_parents; however, because of a) the way levels are numbered starting from 1 and b) the way mmu_page_path sizes its arrays with PT64_ROOT_LEVEL-1 elements, the access can be out of bounds. This is harmless because the code overwrites up to the first two elements of parents->idx and these are initialized, and because the sentinel is not needed in this case---mmu_page_clear_parents exits anyway when it gets to the end of the array. However ubsan complains, and everyone else should too. This fix does three things. First it makes the mmu_page_path arrays PT64_ROOT_LEVEL elements in size, so that we can write to them without checking the level in advance. Second it disintegrates kvm_mmu_pages_init between mmu_unsync_walk (to reset the struct kvm_mmu_pages) and for_each_sp (to place the NULL sentinel at the end of the current path). This is okay because the mmu_page_path is only used in mmu_pages_clear_parents; mmu_pages_clear_parents itself is called within a for_each_sp iterator, and hence always after a call to mmu_pages_next. Third it changes mmu_pages_clear_parents to just use the sentinel to stop iteration, without checking the bounds on level. Reported-by: Sasha Levin <sasha.levin@oracle.com> Reported-by: Mike Krinkin <krinkin.m.u@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: MMU: cleanup handle_abnormal_pfnPaolo Bonzini1-6/+2
The goto and temporary variable are unnecessary, just use return statements. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: VMX: use vmcs_clear/set_bits for debug register exitsPaolo Bonzini1-11/+3
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: turn kvm_kpit_state.reinject into atomic_tRadim Krčmář2-5/+5
Document possible races between readers and concurrent update to the ioctl. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: move PIT timer function initializationRadim Krčmář1-2/+1
We can do it just once. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: don't assume layout of kvm_kpit_stateRadim Krčmář1-4/+8
channels has offset 0 and correct size now, but that can change. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: remove pointless dereference of PITRadim Krčmář1-2/+2
PIT is known at that point. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: remove pit and kvm from kvm_kpit_stateRadim Krčmář2-7/+9
kvm isn't ever used and pit can be accessed with container_of. If you *really* need kvm, pit_state_to_pit(ps)->kvm. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: refactor kvm_free_pitRadim Krčmář1-13/+11
Could be easier to read, but git history will become deeper. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: refactor kvm_create_pitRadim Krčmář1-15/+12
Locks are gone, so we don't need to duplicate error paths. Use goto everywhere. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: remove notifiers from PIT discard policyRadim Krčmář3-13/+38
Discard policy doesn't rely on information from notifiers, so we don't need to register notifiers unconditionally. We kept correct counts in case userspace switched between policies during runtime, but that can be avoided by reseting the state. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: remove unnecessary uses of PIT state lockRadim Krčmář3-14/+8
- kvm_create_pit had to lock only because it exposed kvm->arch.vpit very early, but initialization doesn't use kvm->arch.vpit since the last patch, so we can drop locking. - kvm_free_pit is only run after there are no users of KVM and therefore is the sole actor. - Locking in kvm_vm_ioctl_reinject doesn't do anything, because reinject is only protected at that place. - kvm_pit_reset isn't used anywhere and its locking can be dropped if we hide it. Removing useless locking allows to see what actually is being protected by PIT state lock (values accessible from the guest). Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: pass struct kvm_pit instead of kvm in PITRadim Krčmář3-72/+70
This patch passes struct kvm_pit into internal PIT functions. Those functions used to get PIT through kvm->arch.vpit, even though most of them never used *kvm for other purposes. Another benefit is that we don't need to set kvm->arch.vpit during initialization. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: tone down WARN_ON pit.state_lockRadim Krčmář1-14/+3
If the guest could hit this, it would hang the host kernel, bacause of sheer number of those reports. Internal callers have to be sensible anyway, so we now only check for it in an API function. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: use atomic_t instead of pit.inject_lockRadim Krčmář2-35/+24
The lock was an overkill, the same can be done with atomics. A mb() was added in kvm_pit_ack_irq, to pair with implicit barrier between pit_timer_fn and pit_do_work. The mb() prevents a race that could happen if pending == 0 and irq_ack == 0: kvm_pit_ack_irq: | pit_timer_fn: p = atomic_read(&ps->pending); | | atomic_inc(&ps->pending); | queue_work(pit_do_work); | pit_do_work: | atomic_xchg(&ps->irq_ack, 0); | return; atomic_set(&ps->irq_ack, 1); | if (p == 0) return; | where the interrupt would not be delivered in this tick of pit_timer_fn. PIT would have eventually delivered the interrupt, but we sacrifice perofmance to make sure that interrupts are not needlessly delayed. sfence isn't enough: atomic_dec_if_positive does atomic_read first and x86 can reorder loads before stores. lfence isn't enough: store can pass lfence, turning it into a nop. A compiler barrier would be more than enough as CPU needs to stall for unbelievably long to use fences. This patch doesn't do anything in kvm_pit_reset_reinject, because any order of resets can race, but the result differs by at most one interrupt, which is ok, because it's the same result as if the reset happened at a slightly different time. (Original code didn't protect the reset path with a proper lock, so users have to be robust.) Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: add kvm_pit_reset_reinjectRadim Krčmář1-8/+10
pit_state.pending and pit_state.irq_ack are always reset at the same time. Create a function for them. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: simplify atomics in kvm_pit_ack_irqRadim Krčmář1-11/+1
We already have a helper that does the same thing. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-04KVM: i8254: change PIT discard tick policyRadim Krčmář1-5/+7
Discard policy uses ack_notifiers to prevent injection of PIT interrupts before EOI from the last one. This patch changes the policy to always try to deliver the interrupt, which makes a difference when its vector is in ISR. Old implementation would drop the interrupt, but proposed one injects to IRR, like real hardware would. The old policy breaks legacy NMI watchdogs, where PIT is used through virtual wire (LVT0): PIT never sends an interrupt before receiving EOI, thus a guest deadlock with disabled interrupts will stop NMIs. Note that NMI doesn't do EOI, so PIT also had to send a normal interrupt through IOAPIC. (KVM's PIT is deeply rotten and luckily not used much in modern systems.) Even though there is a chance of regressions, I think we can fix the LVT0 NMI bug without introducing a new tick policy. Cc: <stable@vger.kernel.org> Reported-by: Yuki Shibuya <shibuya.yk@ncos.nec.co.jp> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: apply page track notifierXiao Guangrong2-4/+19
Register the notifier to receive write track event so that we can update our shadow page table It makes kvm_mmu_pte_write() be the callback of the notifier, no function is changed Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: simplify mmu_need_write_protectXiao Guangrong1-22/+7
Now, all non-leaf shadow page are page tracked, if gfn is not tracked there is no non-leaf shadow page of gfn is existed, we can directly make the shadow page of gfn to unsync Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: use page track for non-leaf shadow pagesXiao Guangrong1-5/+21
non-leaf shadow pages are always write protected, it can be the user of page track Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: page track: add notifier supportXiao Guangrong2-0/+74
Notifier list is introduced so that any node wants to receive the track event can register to the list Two APIs are introduced here: - kvm_page_track_register_notifier(): register the notifier to receive track event - kvm_page_track_unregister_notifier(): stop receiving track event by unregister the notifier The callback, node->track_write() is called when a write access on the write tracked page happens Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: clear write-flooding on the fast path of tracked pageXiao Guangrong2-3/+23
If the page fault is caused by write access on write tracked page, the real shadow page walking is skipped, we lost the chance to clear write flooding for the page structure current vcpu is using Fix it by locklessly waking shadow page table to clear write flooding on the shadow page structure out of mmu-lock. So that we change the count to atomic_t Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: let page fault handler be aware tracked pageXiao Guangrong3-7/+55
The page fault caused by write access on the write tracked page can not be fixed, it always need to be emulated. page_fault_handle_page_track() is the fast path we introduce here to skip holding mmu-lock and shadow page table walking However, if the page table is not present, it is worth making the page table entry present and readonly to make the read access happy mmu_need_write_protect() need to be cooked to avoid page becoming writable when making page table present or sync/prefetch shadow page table entries Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: page track: introduce kvm_slot_page_track_{add,remove}_pageXiao Guangrong1-0/+85
These two functions are the user APIs: - kvm_slot_page_track_add_page(): add the page to the tracking pool after that later specified access on that page will be tracked - kvm_slot_page_track_remove_page(): remove the page from the tracking pool, the specified access on the page is not tracked after the last user is gone Both of these are called under the protection both of mmu-lock and kvm->srcu or kvm->slots_lock Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: page track: add the framework of guest page trackingXiao Guangrong3-1/+59
The array, gfn_track[mode][gfn], is introduced in memory slot for every guest page, this is the tracking count for the gust page on different modes. If the page is tracked then the count is increased, the page is not tracked after the count reaches zero We use 'unsigned short' as the tracking count which should be enough as shadow page table only can use 2^14 (2^3 for level, 2^1 for cr4_pae, 2^2 for quadrant, 2^3 for access, 2^1 for nxe, 2^1 for cr0_wp, 2^1 for smep_andnot_wp, 2^1 for smap_andnot_wp, and 2^1 for smm) at most, there is enough room for other trackers Two callbacks, kvm_page_track_create_memslot() and kvm_page_track_free_memslot() are implemented in this patch, they are internally used to initialize and reclaim the memory of the array Currently, only write track mode is supported Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: introduce kvm_mmu_slot_gfn_write_protectXiao Guangrong2-5/+13
Split rmap_write_protect() and introduce the function to abstract the write protection based on the slot This function will be used in the later patch Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: introduce kvm_mmu_gfn_{allow,disallow}_lpageXiao Guangrong2-13/+28
Abstract the common operations from account_shadowed() and unaccount_shadowed(), then introduce kvm_mmu_gfn_disallow_lpage() and kvm_mmu_gfn_allow_lpage() These two functions will be used by page tracking in the later patch Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: rename has_wrprotected_page to mmu_gfn_lpage_is_disallowedXiao Guangrong2-18/+21
kvm_lpage_info->write_count is used to detect if the large page mapping for the gfn on the specified level is allowed, rename it to disallow_lpage to reflect its purpose, also we rename has_wrprotected_page() to mmu_gfn_lpage_is_disallowed() to make the code more clearer Later we will extend this mechanism for page tracking: if the gfn is tracked then large mapping for that gfn on any level is not allowed. The new name is more straightforward Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03kvm: x86: Check dest_map->vector to match eoi signals for rtcJoerg Roedel1-3/+14
Using the vector stored at interrupt delivery makes the eoi matching safe agains irq migration in the ioapic. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03kvm: x86: Track irq vectors in ioapic->rtc_status.dest_mapJoerg Roedel2-1/+10
This allows backtracking later in case the rtc irq has been moved to another vcpu/vector. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03kvm: x86: Convert ioapic->rtc_status.dest_map to a structJoerg Roedel5-16/+26
Currently this is a bitmap which tracks which CPUs we expect an EOI from. Move this bitmap to a struct so that we can track additional information there. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-02kvm: x86: Update tsc multiplier on change.Owen Hofmann1-5/+9
vmx.c writes the TSC_MULTIPLIER field in vmx_vcpu_load, but only when a vcpu has migrated physical cpus. Record the last value written and update in vmx_vcpu_load on any change, otherwise a cpu migration must occur for TSC frequency scaling to take effect. Cc: stable@vger.kernel.org Fixes: ff2c3a1803775cc72dc6f624b59554956396b0ee Signed-off-by: Owen Hofmann <osh@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-29Merge branch 'sched/urgent' into sched/core, to pick up fixes before applying new changesIngo Molnar3-3/+4
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-26KVM: x86: fix root cause for missed hardware breakpointsPaolo Bonzini1-5/+4
Commit 172b2386ed16 ("KVM: x86: fix missed hardware breakpoints", 2016-02-10) worked around a case where the debug registers are not loaded correctly on preemption and on the first entry to KVM_RUN. However, Xiao Guangrong pointed out that the root cause must be that KVM_DEBUGREG_BP_ENABLED is not being set correctly. This can indeed happen due to the lazy debug exit mechanism, which does not call kvm_update_dr7. Fix it by replacing the existing loop (more or less equivalent to kvm_update_dr0123) with calls to all the kvm_update_dr* functions. Cc: stable@vger.kernel.org # 4.1+ Fixes: 172b2386ed16a9143d9a456aae5ec87275c61489 Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-25KVM: Use simple waitqueue for vcpu->wqMarcelo Tosatti1-3/+3
The problem: On -rt, an emulated LAPIC timer instances has the following path: 1) hard interrupt 2) ksoftirqd is scheduled 3) ksoftirqd wakes up vcpu thread 4) vcpu thread is scheduled This extra context switch introduces unnecessary latency in the LAPIC path for a KVM guest. The solution: Allow waking up vcpu thread from hardirq context, thus avoiding the need for ksoftirqd to be scheduled. Normal waitqueues make use of spinlocks, which on -RT are sleepable locks. Therefore, waking up a waitqueue waiter involves locking a sleeping lock, which is not allowed from hard interrupt context. cyclictest command line: This patch reduces the average latency in my tests from 14us to 11us. Daniel writes: Paolo asked for numbers from kvm-unit-tests/tscdeadline_latency benchmark on mainline. The test was run 1000 times on tip/sched/core 4.4.0-rc8-01134-g0905f04: ./x86-run x86/tscdeadline_latency.flat -cpu host with idle=poll. The test seems not to deliver really stable numbers though most of them are smaller. Paolo write: "Anything above ~10000 cycles means that the host went to C1 or lower---the number means more or less nothing in that case. The mean shows an improvement indeed." Before: min max mean std count 1000.000000 1000.000000 1000.000000 1000.000000 mean 5162.596000 2019270.084000 5824.491541 20681.645558 std 75.431231 622607.723969 89.575700 6492.272062 min 4466.000000 23928.000000 5537.926500 585.864966 25% 5163.000000 1613252.750000 5790.132275 16683.745433 50% 5175.000000 2281919.000000 5834.654000 23151.990026 75% 5190.000000 2382865.750000 5861.412950 24148.206168 max 5228.000000 4175158.000000 6254.827300 46481.048691 After min max mean std count 1000.000000 1000.00000 1000.000000 1000.000000 mean 5143.511000 2076886.10300 5813.312474 21207.357565 std 77.668322 610413.09583 86.541500 6331.915127 min 4427.000000 25103.00000 5529.756600 559.187707 25% 5148.000000 1691272.75000 5784.889825 17473.518244 50% 5160.000000 2308328.50000 5832.025000 23464.837068 75% 5172.000000 2393037.75000 5853.177675 24223.969976 max 5222.000000 3922458.00000 6186.720500 42520.379830 [Patch was originaly based on the swait implementation found in the -rt tree. Daniel ported it to mainline's version and gathered the benchmark numbers for tscdeadline_latency test.] Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-rt-users@vger.kernel.org Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1455871601-27484-4-git-send-email-wagi@monom.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-02-25KVM: x86: MMU: fix ubsan index-out-of-range warningMike Krinkin1-1/+1
Ubsan reports the following warning due to a typo in update_accessed_dirty_bits template, the patch fixes the typo: [ 168.791851] ================================================================================ [ 168.791862] UBSAN: Undefined behaviour in arch/x86/kvm/paging_tmpl.h:252:15 [ 168.791866] index 4 is out of range for type 'u64 [4]' [ 168.791871] CPU: 0 PID: 2950 Comm: qemu-system-x86 Tainted: G O L 4.5.0-rc5-next-20160222 #7 [ 168.791873] Hardware name: LENOVO 23205NG/23205NG, BIOS G2ET95WW (2.55 ) 07/09/2013 [ 168.791876] 0000000000000000 ffff8801cfcaf208 ffffffff81c9f780 0000000041b58ab3 [ 168.791882] ffffffff82eb2cc1 ffffffff81c9f6b4 ffff8801cfcaf230 ffff8801cfcaf1e0 [ 168.791886] 0000000000000004 0000000000000001 0000000000000000 ffffffffa1981600 [ 168.791891] Call Trace: [ 168.791899] [<ffffffff81c9f780>] dump_stack+0xcc/0x12c [ 168.791904] [<ffffffff81c9f6b4>] ? _atomic_dec_and_lock+0xc4/0xc4 [ 168.791910] [<ffffffff81da9e81>] ubsan_epilogue+0xd/0x8a [ 168.791914] [<ffffffff81daafa2>] __ubsan_handle_out_of_bounds+0x15c/0x1a3 [ 168.791918] [<ffffffff81daae46>] ? __ubsan_handle_shift_out_of_bounds+0x2bd/0x2bd [ 168.791922] [<ffffffff811287ef>] ? get_user_pages_fast+0x2bf/0x360 [ 168.791954] [<ffffffffa1794050>] ? kvm_largepages_enabled+0x30/0x30 [kvm] [ 168.791958] [<ffffffff81128530>] ? __get_user_pages_fast+0x360/0x360 [ 168.791987] [<ffffffffa181b818>] paging64_walk_addr_generic+0x1b28/0x2600 [kvm] [ 168.792014] [<ffffffffa1819cf0>] ? init_kvm_mmu+0x1100/0x1100 [kvm] [ 168.792019] [<ffffffff8129e350>] ? debug_check_no_locks_freed+0x350/0x350 [ 168.792044] [<ffffffffa1819cf0>] ? init_kvm_mmu+0x1100/0x1100 [kvm] [ 168.792076] [<ffffffffa181c36d>] paging64_gva_to_gpa+0x7d/0x110 [kvm] [ 168.792121] [<ffffffffa181c2f0>] ? paging64_walk_addr_generic+0x2600/0x2600 [kvm] [ 168.792130] [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90 [ 168.792178] [<ffffffffa17d9a4a>] emulator_read_write_onepage+0x27a/0x1150 [kvm] [ 168.792208] [<ffffffffa1794d44>] ? __kvm_read_guest_page+0x54/0x70 [kvm] [ 168.792234] [<ffffffffa17d97d0>] ? kvm_task_switch+0x160/0x160 [kvm] [ 168.792238] [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90 [ 168.792263] [<ffffffffa17daa07>] emulator_read_write+0xe7/0x6d0 [kvm] [ 168.792290] [<ffffffffa183b620>] ? em_cr_write+0x230/0x230 [kvm] [ 168.792314] [<ffffffffa17db005>] emulator_write_emulated+0x15/0x20 [kvm] [ 168.792340] [<ffffffffa18465f8>] segmented_write+0xf8/0x130 [kvm] [ 168.792367] [<ffffffffa1846500>] ? em_lgdt+0x20/0x20 [kvm] [ 168.792374] [<ffffffffa14db512>] ? vmx_read_guest_seg_ar+0x42/0x1e0 [kvm_intel] [ 168.792400] [<ffffffffa1846d82>] writeback+0x3f2/0x700 [kvm] [ 168.792424] [<ffffffffa1846990>] ? em_sidt+0xa0/0xa0 [kvm] [ 168.792449] [<ffffffffa185554d>] ? x86_decode_insn+0x1b3d/0x4f70 [kvm] [ 168.792474] [<ffffffffa1859032>] x86_emulate_insn+0x572/0x3010 [kvm] [ 168.792499] [<ffffffffa17e71dd>] x86_emulate_instruction+0x3bd/0x2110 [kvm] [ 168.792524] [<ffffffffa17e6e20>] ? reexecute_instruction.part.110+0x2e0/0x2e0 [kvm] [ 168.792532] [<ffffffffa14e9a81>] handle_ept_misconfig+0x61/0x460 [kvm_intel] [ 168.792539] [<ffffffffa14e9a20>] ? handle_pause+0x450/0x450 [kvm_intel] [ 168.792546] [<ffffffffa15130ea>] vmx_handle_exit+0xd6a/0x1ad0 [kvm_intel] [ 168.792572] [<ffffffffa17f6a6c>] ? kvm_arch_vcpu_ioctl_run+0xbdc/0x6090 [kvm] [ 168.792597] [<ffffffffa17f6bcd>] kvm_arch_vcpu_ioctl_run+0xd3d/0x6090 [kvm] [ 168.792621] [<ffffffffa17f6a6c>] ? kvm_arch_vcpu_ioctl_run+0xbdc/0x6090 [kvm] [ 168.792627] [<ffffffff8293b530>] ? __ww_mutex_lock_interruptible+0x1630/0x1630 [ 168.792651] [<ffffffffa17f5e90>] ? kvm_arch_vcpu_runnable+0x4f0/0x4f0 [kvm] [ 168.792656] [<ffffffff811eeb30>] ? preempt_notifier_unregister+0x190/0x190 [ 168.792681] [<ffffffffa17e0447>] ? kvm_arch_vcpu_load+0x127/0x650 [kvm] [ 168.792704] [<ffffffffa178e9a3>] kvm_vcpu_ioctl+0x553/0xda0 [kvm] [ 168.792727] [<ffffffffa178e450>] ? vcpu_put+0x40/0x40 [kvm] [ 168.792732] [<ffffffff8129e350>] ? debug_check_no_locks_freed+0x350/0x350 [ 168.792735] [<ffffffff82946087>] ? _raw_spin_unlock+0x27/0x40 [ 168.792740] [<ffffffff8163a943>] ? handle_mm_fault+0x1673/0x2e40 [ 168.792744] [<ffffffff8129daa8>] ? trace_hardirqs_on_caller+0x478/0x6c0 [ 168.792747] [<ffffffff8129dcfd>] ? trace_hardirqs_on+0xd/0x10 [ 168.792751] [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90 [ 168.792756] [<ffffffff81725a80>] do_vfs_ioctl+0x1b0/0x12b0 [ 168.792759] [<ffffffff817258d0>] ? ioctl_preallocate+0x210/0x210 [ 168.792763] [<ffffffff8174aef3>] ? __fget+0x273/0x4a0 [ 168.792766] [<ffffffff8174acd0>] ? __fget+0x50/0x4a0 [ 168.792770] [<ffffffff8174b1f6>] ? __fget_light+0x96/0x2b0 [ 168.792773] [<ffffffff81726bf9>] SyS_ioctl+0x79/0x90 [ 168.792777] [<ffffffff82946880>] entry_SYSCALL_64_fastpath+0x23/0xc1 [ 168.792780] ================================================================================ Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-24KVM: x86: fix conversion of addresses to linear in 32-bit protected modePaolo Bonzini1-2/+2
Commit e8dd2d2d641c ("Silence compiler warning in arch/x86/kvm/emulate.c", 2015-09-06) broke boot of the Hurd. The bug is that the "default:" case actually could modify "la", but after the patch this change is not reflected in *linear. The bug is visible whenever a non-zero segment base causes the linear address to wrap around the 4GB mark. Fixes: e8dd2d2d641cb2724ee10e76c0ad02e04289c017 Cc: stable@vger.kernel.org Reported-by: Aurelien Jarno <aurelien@aurel32.net> Tested-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-24KVM: x86: fix missed hardware breakpointsPaolo Bonzini1-0/+1
Sometimes when setting a breakpoint a process doesn't stop on it. This is because the debug registers are not loaded correctly on VCPU load. The following simple reproducer from Oleg Nesterov tries using debug registers in two threads. To see the bug, run a 2-VCPU guest with "taskset -c 0" and run "./bp 0 1" inside the guest. #include <unistd.h> #include <signal.h> #include <stdlib.h> #include <stdio.h> #include <sys/wait.h> #include <sys/ptrace.h> #include <sys/user.h> #include <asm/debugreg.h> #include <assert.h> #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) unsigned long encode_dr7(int drnum, int enable, unsigned int type, unsigned int len) { unsigned long dr7; dr7 = ((len | type) & 0xf) << (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE); if (enable) dr7 |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)); return dr7; } int write_dr(int pid, int dr, unsigned long val) { return ptrace(PTRACE_POKEUSER, pid, offsetof (struct user, u_debugreg[dr]), val); } void set_bp(pid_t pid, void *addr) { unsigned long dr7; assert(write_dr(pid, 0, (long)addr) == 0); dr7 = encode_dr7(0, 1, DR_RW_EXECUTE, DR_LEN_1); assert(write_dr(pid, 7, dr7) == 0); } void *get_rip(int pid) { return (void*)ptrace(PTRACE_PEEKUSER, pid, offsetof(struct user, regs.rip), 0); } void test(int nr) { void *bp_addr = &&label + nr, *bp_hit; int pid; printf("test bp %d\n", nr); assert(nr < 16); // see 16 asm nops below pid = fork(); if (!pid) { assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0); kill(getpid(), SIGSTOP); for (;;) { label: asm ( "nop; nop; nop; nop;" "nop; nop; nop; nop;" "nop; nop; nop; nop;" "nop; nop; nop; nop;" ); } } assert(pid == wait(NULL)); set_bp(pid, bp_addr); for (;;) { assert(ptrace(PTRACE_CONT, pid, 0, 0) == 0); assert(pid == wait(NULL)); bp_hit = get_rip(pid); if (bp_hit != bp_addr) fprintf(stderr, "ERR!! hit wrong bp %ld != %d\n", bp_hit - &&label, nr); } } int main(int argc, const char *argv[]) { while (--argc) { int nr = atoi(*++argv); if (!fork()) test(nr); } while (wait(NULL) > 0) ; return 0; } Cc: stable@vger.kernel.org Suggested-by: Nadav Amit <namit@cs.technion.ac.il> Reported-by: Andrey Wagin <avagin@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-24x86: Fix misspellings in commentsAdam Buchbinder3-5/+5
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: trivial@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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