- 30 Jan, 2013 1 commit
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Christian Borntraeger authored
On store status we need to copy the current state of registers into a save area. Currently we might save stale versions: The sie state descriptor doesnt have fields for guest ACRS,FPRS, those registers are simply stored in the host registers. The host program must copy these away if needed. We do that in vcpu_put/load. If we now do a store status in KVM code between vcpu_put/load, the saved values are not up-to-date. Lets collect the ACRS/FPRS before saving them. This also fixes some strange problems with hotplug and virtio-ccw, since the low level machine check handler (on hotplug a machine check will happen) will revalidate all registers with the content of the save area. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> CC: stable@vger.kernel.org Signed-off-by:
Gleb Natapov <gleb@redhat.com>
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- 29 Jan, 2013 5 commits
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Raghavendra K T authored
yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three successive failures of yield_to we assume we are in potential undercommit case and abort from PLE handler. The assumption is backed by low probability of wrong decision for even worst case scenarios such as average runqueue length between 1 and 2. More detail on rationale behind using three tries: if p is the probability of finding rq length one on a particular cpu, and if we do n tries, then probability of exiting ple handler is: p^(n+1) [ because we would have come across one source with rq length 1 and n target cpu rqs with length 1 ] so num tries: probability of aborting ple handler (1.5x overcommit) 1 1/4 2 1/8 3 1/16 We can increase this probability with more tries, but the problem is the overhead. Also, If we have tried three times that means we would have iterated over 3 good eligible vcpus along with many non-eligible candidates. In worst case if we iterate all the vcpus, we reduce 1x performance and overcommit performance get hit. note that we do not update last boosted vcpu in failure cases. Thank Avi for raising question on aborting after first fail from yield_to. Reviewed-by:
Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by:
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Tested-by:
Chegu Vinod <chegu_vinod@hp.com> Signed-off-by:
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Peter Zijlstra authored
In case of undercomitted scenarios, especially in large guests yield_to overhead is significantly high. when run queue length of source and target is one, take an opportunity to bail out and return -ESRCH. This return condition can be further exploited to quickly come out of PLE handler. (History: Raghavendra initially worked on break out of kvm ple handler upon seeing source runqueue length = 1, but it had to export rq length). Peter came up with the elegant idea of return -ESRCH in scheduler core. Signed-off-by:
Peter Zijlstra <peterz@infradead.org> Raghavendra, Checking the rq length of target vcpu condition added.(thanks Avi) Reviewed-by:
Andrew Jones <drjones@redhat.com> Tested-by:
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Yang Zhang authored
Virtual interrupt delivery avoids KVM to inject vAPIC interrupts manually, which is fully taken care of by the hardware. This needs some special awareness into existing interrupr injection path: - for pending interrupt, instead of direct injection, we may need update architecture specific indicators before resuming to guest. - A pending interrupt, which is masked by ISR, should be also considered in above update action, since hardware will decide when to inject it at right time. Current has_interrupt and get_interrupt only returns a valid vector from injection p.o.v. Reviewed-by:
Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
Kevin Tian <kevin.tian@intel.com> Signed-off-by:
Yang Zhang <yang.z.zhang@Intel.com> Signed-off-by:
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Yang Zhang authored
basically to benefit from apicv, we need to enable virtualized x2apic mode. Currently, we only enable it when guest is really using x2apic. Also, clear MSR bitmap for corresponding x2apic MSRs when guest enabled x2apic: 0x800 - 0x8ff: no read intercept for apicv register virtualization, except APIC ID and TMCCT which need software's assistance to get right value. Reviewed-by: -
Yang Zhang authored
- APIC read doesn't cause VM-Exit - APIC write becomes trap-like Reviewed-by:
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- 27 Jan, 2013 3 commits
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Alex Williamson authored
We've been ignoring read-only mappings and programming everything into the iommu as read-write. Fix this to only include the write access flag when read-only is not set. Signed-off-by:
Alex Williamson <alex.williamson@redhat.com> Signed-off-by:
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Alex Williamson authored
Memory slot flags can be altered without changing other parameters of the slot. The read-only attribute is the only one the IOMMU cares about, so generate an un-map, re-map when this occurs. This also avoid unnecessarily re-mapping the slot when no IOMMU visible changes are made. Reviewed-by:
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by:
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Avi Kivity authored
'pushq' doesn't exist on i386. Replace with 'push', which should work since the operand is a register. Signed-off-by:
Avi Kivity <avi.kivity@gmail.com> Signed-off-by:
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- 24 Jan, 2013 17 commits
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Gleb Natapov authored
If emulate_invalid_guest_state=false vmx->emulation_required is never actually used, but it ends up to be always set to true since handle_invalid_guest_state(), the only place it is reset back to false, is never called. This, besides been not very clean, makes vmexit and vmentry path to check emulate_invalid_guest_state needlessly. The patch fixes that by keeping emulation_required coherent with emulate_invalid_guest_state setting. Signed-off-by:
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Gleb Natapov authored
If VMX reports segment as unusable, zero descriptor passed by the emulator before returning. Such descriptor will be considered not present by the emulator. Signed-off-by:
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Gleb Natapov authored
The function deals with code segment too. Signed-off-by:
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Gleb Natapov authored
Usability is returned in unusable field, so not need to clobber entire AR. Callers have to know how to deal with unusable segments already since if emulate_invalid_guest_state=true AR is not zeroed. Signed-off-by:
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Gleb Natapov authored
vmx->rmode.vm86_active is never true is unrestricted guest is enabled. Make it more explicit that neither enter_pmode() nor enter_rmode() is called in this case. Signed-off-by:
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Gleb Natapov authored
There is no reason for it. If state is suitable for vmentry it will be detected during guest entry and no emulation will happen. Signed-off-by:
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Gleb Natapov authored
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Gleb Natapov authored
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Gleb Natapov authored
Since vmx_get_cpl() always returns 0 when VCPU is in real mode it is no longer needed. Also reset CPL cache to zero during transaction to protected mode since transaction may happen while CS.selectors & 3 != 0, but in reality CPL is 0. Signed-off-by:
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Avi Kivity authored
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Avi Kivity authored
Make fastop opcodes usable in other emulations. Reviewed-by:
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Avi Kivity authored
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Avi Kivity authored
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Avi Kivity authored
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Avi Kivity authored
This is a bit of a special case since we don't have the usual byte/word/long/quad switch; instead we switch on the condition code embedded in the instruction. Reviewed-by:
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Avi Kivity authored
SHL, SHR, ROL, ROR, RCL, RCR, SAR, SAL Reviewed-by:
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Avi Kivity authored
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- 22 Jan, 2013 3 commits
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Xiao Guangrong authored
The current reexecute_instruction can not well detect the failed instruction emulation. It allows guest to retry all the instructions except it accesses on error pfn For example, some cases are nested-write-protect - if the page we want to write is used as PDE but it chains to itself. Under this case, we should stop the emulation and report the case to userspace Reviewed-by:
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Xiao Guangrong authored
Currently, reexecute_instruction refused to retry all instructions if tdp is enabled. If nested npt is used, the emulation may be caused by shadow page, it can be fixed by dropping the shadow page. And the only condition that tdp can not retry the instruction is the access fault on error pfn Reviewed-by:
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Xiao Guangrong authored
Little cleanup for reexecute_instruction, also use gpa_to_gfn in retry_instruction Reviewed-by:
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- 17 Jan, 2013 4 commits
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Takuya Yoshikawa authored
One such variable, slot, is enough for holding a pointer temporarily. We also remove another local variable named slot, which is limited in a block, since it is confusing to have the same name in this function. Reviewed-by:
Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by:
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Takuya Yoshikawa authored
Don't need the check for deleting an existing slot or just modifiying the flags. Reviewed-by:
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Takuya Yoshikawa authored
This makes the separation between the sanity checks and the rest of the code a bit clearer. Reviewed-by:
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Cong Ding authored
the variable inti should be freed in the branch CPUSTAT_STOPPED. Signed-off-by:
Cong Ding <dinggnu@gmail.com> Signed-off-by:
Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by:
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- 14 Jan, 2013 7 commits
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Takuya Yoshikawa authored
If the userspace starts dirty logging for a large slot, say 64GB of memory, kvm_mmu_slot_remove_write_access() needs to hold mmu_lock for a long time such as tens of milliseconds. This patch controls the lock hold time by asking the scheduler if we need to reschedule for others. One penalty for this is that we need to flush TLBs before releasing mmu_lock. But since holding mmu_lock for a long time does affect not only the guest, vCPU threads in other words, but also the host as a whole, we should pay for that. In practice, the cost will not be so high because we can protect a fair amount of memory before being rescheduled: on my test environment, cond_resched_lock() was called only once for protecting 12GB of memory even without THP. We can also revisit Avi's "unlocked TLB flush" work later for completely suppressing extra TLB flushes if needed. Reviewed-by:
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Takuya Yoshikawa authored
Better to place mmu_lock handling and TLB flushing code together since this is a self-contained function. Reviewed-by:
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Takuya Yoshikawa authored
No reason to make callers take mmu_lock since we do not need to protect kvm_mmu_change_mmu_pages() and kvm_mmu_slot_remove_write_access() together by mmu_lock in kvm_arch_commit_memory_region(): the former calls kvm_mmu_commit_zap_page() and flushes TLBs by itself. Note: we do not need to protect kvm->arch.n_requested_mmu_pages by mmu_lock as can be seen from the fact that it is read locklessly. Reviewed-by:
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Takuya Yoshikawa authored
Not needed any more. Reviewed-by:
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Takuya Yoshikawa authored
This makes it possible to release mmu_lock and reschedule conditionally in a later patch. Although this may increase the time needed to protect the whole slot when we start dirty logging, the kernel should not allow the userspace to trigger something that will hold a spinlock for such a long time as tens of milliseconds: actually there is no limit since it is roughly proportional to the number of guest pages. Another point to note is that this patch removes the only user of slot_bitmap which will cause some problems when we increase the number of slots further. Reviewed-by:
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Takuya Yoshikawa authored
No longer need to care about the mapping level in this function. Reviewed-by:
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Takuya Yoshikawa authored
Calling kvm_mmu_slot_remove_write_access() for a deleted slot does nothing but search for non-existent mmu pages which have mappings to that deleted memory; this is safe but a waste of time. Since we want to make the function rmap based in a later patch, in a manner which makes it unsafe to be called for a deleted slot, we makes the caller see if the slot is non-zero and being dirty logged. Reviewed-by:
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