- 20 Mar, 2012 1 commit
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Marcelo Tosatti authored
Upon resume from hibernation, CPU 0's hvclock area contains the old values for system_time and tsc_timestamp. It is necessary for the hypervisor to update these values with uptodate ones before the CPU uses them. Abstract TSC's save/restore sched_clock_state functions and use restore_state to write to KVM_SYSTEM_TIME MSR, forcing an update. Also move restore_sched_clock_state before __restore_processor_state, since the later calls CONFIG_LOCK_STAT's lockstat_clock (also for TSC). Thanks to Igor Mammedov for tracking it down. Fixes suspend-to-disk with kvmclock. Reviewed-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
Avi Kivity <avi@redhat.com>
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- 08 Mar, 2012 37 commits
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Nadav Har'El authored
The code which checks whether to inject a pagefault to L1 or L2 (in nested VMX) was wrong, incorrect in how it checked the PF_VECTOR bit. Thanks to Dan Carpenter for spotting this. Signed-off-by:
Nadav Har'El <nyh@il.ibm.com> Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Nicolae Mogoreanu authored
When CPUID Fn8000_0001_EAX reports 0x00100f22 Windows 7 x64 guest tries to set bit 3 in MSRC001_0015 in nt!KiDisableCacheErrataSource and fails. This patch will ignore this step and allow things to move on without having to fake CPUID value. Signed-off-by:
Nicolae Mogoreanu <mogoreanu@gmail.com> Signed-off-by:
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Davidlohr Bueso authored
The reset_rsvds_bits_mask() function can use the guest walker's root level number instead of using a separate 'level' variable. Signed-off-by:
Davidlohr Bueso <dave@gnu.org> Signed-off-by:
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Gleb Natapov authored
Currently pmu emulation emulates fixed counter 2 as bus cycles architectural counter, but since commit 9c1497ea perf has pseudo encoding for it. Use it. Signed-off-by:
Gleb Natapov <gleb@redhat.com> Signed-off-by:
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Gleb Natapov authored
If eventsel has EDGE, INV or CMASK set we should create raw counter for it, but the check is done on a wrong variable. Fix it. Signed-off-by:
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Gleb Natapov authored
Print warning once if pin control bit is set in eventsel msr since emulation does not support it yet. Signed-off-by:
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Avi Kivity authored
Shared MSRs (MSR_*STAR and related) are stored in both vmx->guest_msrs and in the CPU registers, but vmx_set_msr() only updated memory. Prior to 46199f33, this didn't matter, since we called vmx_load_host_state(), which scheduled a vmx_save_host_state(), which re-synchronized the CPU state, but now we don't, so the CPU state will not be synchronized until the next exit to host userspace. This mostly affects nested vmx workloads, which play with these MSRs a lot. Fix by loading the MSR eagerly. Signed-off-by:
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Alex Shi authored
Using 'int' type is not suitable for a 'long' object. So, correct it. Signed-off-by:
Alex Shi <alex.shi@intel.com> Signed-off-by:
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Jan Kiszka authored
PCI 2.3 allows to generically disable IRQ sources at device level. This enables us to share legacy IRQs of such devices with other host devices when passing them to a guest. The new IRQ sharing feature introduced here is optional, user space has to request it explicitly. Moreover, user space can inform us about its view of PCI_COMMAND_INTX_DISABLE so that we can avoid unmasking the interrupt and signaling it if the guest masked it via the virtualized PCI config space. Signed-off-by:
Jan Kiszka <jan.kiszka@siemens.com> Acked-by:
Alex Williamson <alex.williamson@redhat.com> Acked-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
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Avi Kivity authored
If some vcpus are created before KVM_CREATE_IRQCHIP, then irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading to potential NULL pointer dereferences. Fix by: - ensuring that no vcpus are installed when KVM_CREATE_IRQCHIP is called - ensuring that a vcpu has an apic if it is installed after KVM_CREATE_IRQCHIP This is somewhat long winded because vcpu->arch.apic is created without kvm->lock held. Based on earlier patch by Michael Ellerman. Signed-off-by:
Michael Ellerman <michael@ellerman.id.au> Signed-off-by:
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Kevin Wolf authored
Task switches can switch between Protected Mode and VM86. The current mode must be updated during the task switch emulation so that the new segment selectors are interpreted correctly. In order to let privilege checks succeed, rflags needs to be updated in the vcpu struct as this causes a CPL update. Signed-off-by:
Kevin Wolf <kwolf@redhat.com> Signed-off-by:
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Kevin Wolf authored
Keep CPL at 0 in real mode and at 3 in VM86. In protected/long mode, use RPL rather than DPL of the code segment. Signed-off-by:
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Kevin Wolf authored
Setting the segment DPL to 0 for at least the VM86 code segment makes the VM entry fail on VMX. Signed-off-by:
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Kevin Wolf authored
Currently, all task switches check privileges against the DPL of the TSS. This is only correct for jmp/call to a TSS. If a task gate is used, the DPL of this take gate is used for the check instead. Exceptions, external interrupts and iret shouldn't perform any check. [avi: kill kvm-kmod remnants] Signed-off-by:
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Danny Kukawka authored
arch/powerpc/kvm/book3s_hv.c: included 'linux/sched.h' twice, remove the duplicate. Signed-off-by:
Danny Kukawka <danny.kukawka@bisect.de> Signed-off-by:
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Gleb Natapov authored
Signed-off-by:
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Takuya Yoshikawa authored
Other threads may process the same page in that small window and skip TLB flush and then return before these functions do flush. Signed-off-by:
Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by:
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Takuya Yoshikawa authored
Some members of kvm_memory_slot are not used by every architecture. This patch is the first step to make this difference clear by introducing kvm_memory_slot::arch; lpage_info is moved into it. Signed-off-by:
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Takuya Yoshikawa authored
Narrow down the controlled text inside the conditional so that it will include lpage_info and rmap stuff only. For this we change the way we check whether the slot is being created from "if (npages && !new.rmap)" to "if (npages && !old.npages)". We also stop checking if lpage_info is NULL when we create lpage_info because we do it from inside the slot creation code block. Signed-off-by:
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Takuya Yoshikawa authored
This makes it easy to make lpage_info architecture specific. Signed-off-by:
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Takuya Yoshikawa authored
This patch cleans up the code and removes the "(void)level;" warning suppressor. Note that we can also use this for PT_PAGE_TABLE_LEVEL to treat every level uniformly later. Signed-off-by:
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Christian Borntraeger authored
There are several cases were we need the control registers for userspace. Lets also provide those in kvm_run. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by:
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Jens Freimann authored
When we do a stop and store status we need to pass ACTION_STOP_ON_STOP flag to __sigp_stop(). Signed-off-by:
Jens Freimann <jfrei@linux.vnet.ibm.com> Signed-off-by:
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Jens Freimann authored
In __inject_sigp_stop() do nothing when the CPU is already in stopped state. Signed-off-by:
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Jens Freimann authored
On reboot the guest sends in smp_send_stop() a sigp stop to all CPUs except for current CPU. Then the guest switches to the IPL cpu by sending a restart to the IPL CPU, followed by a sigp stop to the current cpu. Since restart is handled by userspace it's possible that the restart is delivered before the old stop. This means that the IPL CPU isn't restarted and we have no running CPUs. So let's make sure that there is no stop action pending when we do the restart. Signed-off-by:
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Jens Freimann authored
In handle_stop() handle the stop bit before doing the store status as described for "Stop and Store Status" in the Principles of Operation. We have to give up the local_int.lock before calling kvm store status since it calls gmap_fault() which might sleep. Since local_int.lock only protects local_int.* and not guest memory we can give up the lock. Signed-off-by:
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Christian Borntraeger authored
commit 7eef87dc (KVM: s390: fix register setting) added a load of the floating point control register to the KVM_SET_FPU path. Lets make sure that the fpc is valid. Signed-off-by:
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Takuya Yoshikawa authored
This patch fixes a race introduced by: commit 95d4c16c KVM: Optimize dirty logging by rmap_write_protect() During protecting pages for dirty logging, other threads may also try to protect a page in mmu_sync_children() or kvm_mmu_get_page(). In such a case, because get_dirty_log releases mmu_lock before flushing TLB's, the following race condition can happen: A (get_dirty_log) B (another thread) lock(mmu_lock) clear pte.w unlock(mmu_lock) lock(mmu_lock) pte.w is already cleared unlock(mmu_lock) skip TLB flush return ... TLB flush Though thread B assumes the page has already been protected when it returns, the remaining TLB entry will break that assumption. This patch fixes this problem by making get_dirty_log hold the mmu_lock until it flushes the TLB's. Signed-off-by:
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Raghavendra K T authored
yield_on_hlt was introduced for CPU bandwidth capping. Now it is redundant with CFS hardlimit. yield_on_hlt also complicates the scenario in paravirtual environment, that needs to trap halt. for e.g. paravirtualized ticket spinlocks. Acked-by:
Anthony Liguori <aliguori@us.ibm.com> Signed-off-by:
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Signed-off-by:
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Zachary Amsden authored
This allows us to track the original nanosecond and counter values at each phase of TSC writing by the guest. This gets us perfect offset matching for stable TSC systems, and perfect software computed TSC matching for machines with unstable TSC. Signed-off-by:
Zachary Amsden <zamsden@gmail.com> Signed-off-by:
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Zachary Amsden authored
During a host suspend, TSC may go backwards, which KVM interprets as an unstable TSC. Technically, KVM should not be marking the TSC unstable, which causes the TSC clocksource to go bad, but we need to be adjusting the TSC offsets in such a case. Dealing with this issue is a little tricky as the only place we can reliably do it is before much of the timekeeping infrastructure is up and running. On top of this, we are not in a KVM thread context, so we may not be able to safely access VCPU fields. Instead, we compute our best known hardware offset at power-up and stash it to be applied to all VCPUs when they actually start running. Signed-off-by:
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Marcelo Tosatti authored
Redefine the API to take a parameter indicating whether an adjustment is in host or guest cycles. Signed-off-by:
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Zachary Amsden authored
The variable last_host_tsc was removed from upstream code. I am adding it back for two reasons. First, it is unnecessary to use guest TSC computation to conclude information about the host TSC. The guest may set the TSC backwards (this case handled by the previous patch), but the computation of guest TSC (and fetching an MSR) is significanlty more work and complexity than simply reading the hardware counter. In addition, we don't actually need the guest TSC for any part of the computation, by always recomputing the offset, we can eliminate the need to deal with the current offset and any scaling factors that may apply. The second reason is that later on, we are going to be using the host TSC value to restore TSC offsets after a host S4 suspend, so we need to be reading the host values, not the guest values here. Signed-off-by:
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Zachary Amsden authored
The variable last_guest_tsc was being used as an ad-hoc indicator that guest TSC has been initialized and recorded correctly. However, it may not have been, it could be that guest TSC has been set to some large value, the back to a small value (by, say, a software reboot). This defeats the logic and causes KVM to falsely assume that the guest TSC has gone backwards, marking the host TSC unstable, which is undesirable behavior. In addition, rather than try to compute an offset adjustment for the TSC on unstable platforms, just recompute the whole offset. This allows us to get rid of one callsite for adjust_tsc_offset, which is problematic because the units it takes are in guest units, but here, the computation was originally being done in host units. Doing this, and also recording last_guest_tsc when the TSC is written allow us to remove the tricky logic which depended on last_guest_tsc being zero to indicate a reset of uninitialized value. Instead, we now have the guarantee that the guest TSC offset is always at least something which will get us last_guest_tsc. Signed-off-by:
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Zachary Amsden authored
Currently, when the TSC is written by the guest, the variable ns is updated to force the current write to appear to have taken place at the time of the first write in this sync phase. This leaves a cliff at the end of the match window where updates will fall of the end. There are two scenarios where this can be a problem in practe - first, on a system with a large number of VCPUs, the sync period may last for an extended period of time. The second way this can happen is if the VM reboots very rapidly and we catch a VCPU TSC synchronization just around the edge. We may be unaware of the reboot, and thus the first VCPU might synchronize with an old set of the timer (at, say 0.97 seconds ago, when first powered on). The second VCPU can come in 0.04 seconds later to try to synchronize, but it misses the window because it is just over the threshold. Instead, stop doing this artificial setback of the ns variable and just update it with every write of the TSC. It may be observed that doing so causes values computed by compute_guest_tsc to diverge slightly across CPUs - note that the last_tsc_ns and last_tsc_write variable are used here, and now they last_tsc_ns will be different for each VCPU, reflecting the actual time of the update. However, compute_guest_tsc is used only for guests which already have TSC stability issues, and further, note that the previous patch has caused last_tsc_write to be incremented by the difference in nanoseconds, converted back into guest cycles. As such, only boundary rounding errors should be visible, which given the resolution in nanoseconds, is going to only be a few cycles and only visible in cross-CPU consistency tests. The problem can be fixed by adding a new set of variables to track the start offset and start write value for the current sync cycle. Signed-off-by:
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Zachary Amsden authored
There are a few improvements that can be made to the TSC offset matching code. First, we don't need to call the 128-bit multiply (especially on a constant number), the code works much nicer to do computation in nanosecond units. Second, the way everything is setup with software TSC rate scaling, we currently have per-cpu rates. Obviously this isn't too desirable to use in practice, but if for some reason we do change the rate of all VCPUs at runtime, then reset the TSCs, we will only want to match offsets for VCPUs running at the same rate. Finally, for the case where we have an unstable host TSC, but rate scaling is being done in hardware, we should call the platform code to compute the TSC offset, so the math is reorganized to recompute the base instead, then transform the base into an offset using the existing API. [avi: fix 64-bit division on i386] Signed-off-by:
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Zachary Amsden authored
This requires some restructuring; rather than use 'virtual_tsc_khz' to indicate whether hardware rate scaling is in effect, we consider each VCPU to always have a virtual TSC rate. Instead, there is new logic above the vendor-specific hardware scaling that decides whether it is even necessary to use and updates all rate variables used by common code. This means we can simply query the virtual rate at any point, which is needed for software rate scaling. There is also now a threshold added to the TSC rate scaling; minor differences and variations of measured TSC rate can accidentally provoke rate scaling to be used when it is not needed. Instead, we have a tolerance variable called tsc_tolerance_ppm, which is the maximum variation from user requested rate at which scaling will be used. The default is 250ppm, which is the half the threshold for NTP adjustment, allowing for some hardware variation. In the event that hardware rate scaling is not available, we can kludge a bit by forcing TSC catchup to turn on when a faster than hardware speed has been requested, but there is nothing available yet for the reverse case; this requires a trap and emulate software implementation for RDTSC, which is still forthcoming. [avi: fix 64-bit division on i386] Signed-off-by:
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- 05 Mar, 2012 2 commits
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Marcelo Tosatti authored
Increase recommended max vcpus from 64 to 160 (tested internally at Red Hat). Signed-off-by:
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Igor Mammedov authored
When kvm guest uses kvmclock, it may hang on vcpu hot-plug. This is caused by an overflow in pvclock_get_nsec_offset, u64 delta = tsc - shadow->tsc_timestamp; which in turn is caused by an undefined values from percpu hv_clock that hasn't been initialized yet. Uninitialized clock on being booted cpu is accessed from start_secondary -> smp_callin -> smp_store_cpu_info -> identify_secondary_cpu -> mtrr_ap_init -> mtrr_restore -> stop_machine_from_inactive_cpu -> queue_stop_cpus_work ... -> sched_clock -> kvm_clock_read which is well before x86_cpuinit.setup_percpu_clockev call in start_secondary, where percpu clock is initialized. This patch introduces a hook that allows to setup/initialize per_cpu clock early and avoid overflow due to reading - undefined values - old values if cpu was offlined and then onlined again Another possible early user of this clock source is ftrace that accesses it to get timestamps for ring buffer entries. So if mtrr_ap_init is moved from identify_secondary_cpu to past x86_cpuinit.setup_percpu_clockev in start_secondary, ftrace may cause the same overflow/hang on cpu hot-plug anyway. More complete description of the problem: https://lkml.org/lkml/2012/2/2/101 Credits to Marcelo Tosatti <mtosatti@redhat.com> for hook idea. Acked-by:Igor Mammedov <imammedo@redhat.com> Signed-off-by:
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