- 16 May, 2014 13 commits
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Paolo Bonzini authored
Merge tag 'kvm-s390-20140516' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next 1. Correct locking for lazy storage key handling A test loop with multiple CPUs triggered a race in the lazy storage key handling as introduced by commit 934bc131 (KVM: s390: Allow skeys to be enabled for the current process). This race should not happen with Linux guests, but let's fix it anyway. Patch touches !/kvm/ code, but is from the s390 maintainer. 2. Better handling of broken guests If we detect a program check loop we stop the guest instead of wasting CPU cycles. 3. Better handling on MVPG emulation The move page handling is improved to be architecturally correct. 3. Trace point rework Let's rework the kvm trace points to have a common header file (for later perf usage) and provided a table based instruction decoder. 4. Interpretive execution of SIGP external call Let the hardware handle most cases of SIGP external call (IPI) and wire up the fixup code for the corner cases. 5. Initial preparations for the IBC facility Prepare the code to handle instruction blocking
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Michael Mueller authored
This patch splits the SIE state guest prefix at offset 4 into a prefix bit field. Additionally it provides the access functions: - kvm_s390_get_prefix() - kvm_s390_set_prefix() to access the prefix per vcpu. Signed-off-by:
Michael Mueller <mimu@linux.vnet.ibm.com> Reviewed-by:
Cornelia Huck <cornelia.huck@de.ibm.com> Acked-by:
Christian Borntraeger <borntraeger@de.ibm.com>
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Michael Mueller authored
The patch adds functionality to retrieve the IBC configuration by means of function sclp_get_ibc(). Signed-off-by:
Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by:
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David Hildenbrand authored
If the sigp interpretation facility is installed, most SIGP EXTERNAL CALL operations will be interpreted instead of intercepted. A partial execution interception will occurr at the sending cpu only if the target cpu is in the wait state ("W" bit in the cpuflags set). Instruction interception will only happen in error cases (e.g. cpu addr invalid). As a sending cpu might set the external call interrupt pending flags at the target cpu at every point in time, we can't handle this kind of interrupt using our kvm interrupt injection mechanism. The injection will be done automatically by the SIE when preparing the start of the target cpu. Signed-off-by:David Hildenbrand <dahi@linux.vnet.ibm.com> Reviewed-by:
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Alexander Yarygin authored
The current trace definition doesn't work very well with the perf tool. Perf shows a "insn_to_mnemonic not found" message. Let's handle the decoding completely in a parseable format. Signed-off-by:
Alexander Yarygin <yarygin@linux.vnet.ibm.com> Acked-by:
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Alexander Yarygin authored
This patch adds a new decoder of SIE intercepted instructions. The decoder implemented as a macro and potentially can be used in both kernelspace and userspace. Note that this simplified instruction decoder is only intended to be used with the subset of instructions that may cause a SIE intercept. Signed-off-by:
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Alexander Yarygin authored
Use the symbolic translation tables from sie.h for decoding diag, sigp and sie exit codes. Signed-off-by:
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Alexander Yarygin authored
This patch defines tables of reasons for exiting from SIE mode in a new sie.h header file. Tables contain SIE intercepted codes, intercepted instructions and program interruptions codes. Signed-off-by:
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Thomas Huth authored
Use the new helper function kvm_arch_fault_in_page() for faulting-in the guest pages and only inject addressing errors when we've really hit a bad address (and return other error codes to userspace instead). Signed-off-by:
Thomas Huth <thuth@linux.vnet.ibm.com> Reviewed-by:
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Thomas Huth authored
Rework the function kvm_arch_fault_in_sync() to become a proper helper function for faulting-in a guest page. Now it takes the guest address as a parameter and does not ignore the possible error code from gmap_fault() anymore (which could cause undetected error conditions before). Signed-off-by:
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Thomas Huth authored
If the new PSW for program interrupts is invalid, the VM ends up in an endless loop of specification exceptions. Since there is not much left we can do in this case, we should better drop to userspace instead so that the crash can be reported to the user. Signed-off-by:
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Thomas Huth authored
As a program status word is also invalid (and thus generates an specification exception) if the instruction address is not even, we should test this in is_valid_psw(), too. This patch also exports the function so that it becomes available for other parts of the S390 KVM code as well. Signed-off-by:
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Martin Schwidefsky authored
Use the mm semaphore to serialize multiple invocations of s390_enable_skey. The second CPU faulting on a storage key operation needs to wait for the completion of the page table update. Taking the mm semaphore writable has the positive side-effect that it prevents any host faults from taking place which does have implications on keys vs PGSTE. Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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- 12 May, 2014 1 commit
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Jan Kiszka authored
Regression of 346874c9: PAE is set in long mode, but that does not mean we have valid PDPTRs. Signed-off-by:
Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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- 08 May, 2014 1 commit
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Gabriel L. Somlo authored
Treat monitor and mwait instructions as nop, which is architecturally correct (but inefficient) behavior. We do this to prevent misbehaving guests (e.g. OS X <= 10.7) from crashing after they fail to check for monitor/mwait availability via cpuid. Since mwait-based idle loops relying on these nop-emulated instructions would keep the host CPU pegged at 100%, do NOT advertise their presence via cpuid, to prevent compliant guests from using them inadvertently. Signed-off-by:
Gabriel L. Somlo <somlo@cmu.edu> Signed-off-by:
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- 07 May, 2014 3 commits
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Michael S. Tsirkin authored
It seems that it's easy to implement the EOI assist on top of the PV EOI feature: simply convert the page address to the format expected by PV EOI. Notes: -"No EOI required" is set only if interrupt injected is edge triggered; this is true because level interrupts are going through IOAPIC which disables PV EOI. In any case, if guest triggers EOI the bit will get cleared on exit. -For migration, set of HV_X64_MSR_APIC_ASSIST_PAGE sets KVM_PV_EOI_EN internally, so restoring HV_X64_MSR_APIC_ASSIST_PAGE seems sufficient In any case, bit is cleared on exit so worst case it's never re-enabled -no handling of PV EOI data is performed at HV_X64_MSR_EOI write; HV_X64_MSR_EOI is a separate optimization - it's an X2APIC replacement that lets you do EOI with an MSR and not IO. Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
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Nadav Amit authored
In long-mode, bit 7 in the PDPTE is not reserved only if 1GB pages are supported by the CPU. Currently the bit is considered by KVM as always reserved. Signed-off-by:
Nadav Amit <namit@cs.technion.ac.il> Signed-off-by:
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Nadav Amit authored
The RSP register is not automatically cached, causing mov DR instruction with RSP to fail. Instead the regular register accessing interface should be used. Signed-off-by:
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- 06 May, 2014 8 commits
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Bandan Das authored
Some checks are common to all, and moreover, according to the spec, the check for whether any bits beyond the physical address width are set are also applicable to all of them Signed-off-by:
Bandan Das <bsd@redhat.com> Signed-off-by:
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Bandan Das authored
The spec mandates that if the vmptrld or vmclear address is equal to the vmxon region pointer, the instruction should fail with error "VMPTRLD with VMXON pointer" or "VMCLEAR with VMXON pointer" Signed-off-by:
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Bandan Das authored
Currently, the vmxon region isn't used in the nested case. However, according to the spec, the vmxon instruction performs additional sanity checks on this region and the associated pointer. Modify emulated vmxon to better adhere to the spec requirements Signed-off-by:
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Bandan Das authored
Our common function for vmptr checks (in 2/4) needs to fetch the memory address Signed-off-by:
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Paolo Bonzini authored
Merge tag 'kvm-s390-20140506' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next 1. Fixes an error return code for the breakpoint setup 2. External interrupt fixes 2.1. Some interrupt conditions like cpu timer or clock comparator stay pending even after the interrupt is injected. If the external new PSW is enabled for interrupts this will result in an endless loop. Usually this indicates a programming error in the guest OS. Lets detect such situations and go to userspace. We will provide a QEMU patch that sets the guest in panicked/crashed state to avoid wasting CPU cycles. 2.2 Resend external interrupts back to the guest if the HW could not do it. -
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Thomas Huth authored
The external interrupt interception can only occur in rare cases, e.g. when the PSW of the interrupt handler has a bad value. The old handler for this interception simply ignored these events (except for increasing the exit_external_interrupt counter), but for proper operation we either have to inject the interrupts manually or we should drop to userspace in case of errors. Signed-off-by:
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Thomas Huth authored
Add an interface to inject clock comparator and CPU timer interrupts into the guest. This is needed for handling the external interrupt interception. Signed-off-by:
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Dan Carpenter authored
When copy_from_user() fails, this code returns the number of bytes remaining instead of a negative error code. The positive number is returned to the user but otherwise it is harmless. Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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- 05 May, 2014 2 commits
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Ulrich Obergfell authored
This patch moves the 'kvm_pio' tracepoint to emulator_pio_in_emulated() and emulator_pio_out_emulated(), and it adds an argument (a pointer to the 'pio_data'). A single 8-bit or 16-bit or 32-bit data item is fetched from 'pio_data' (depending on 'size'), and the value is included in the trace record ('val'). If 'count' is greater than one, this is indicated by the string "(...)" in the trace output. Signed-off-by:Ulrich Obergfell <uobergfe@redhat.com> Reviewed-by:
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by:
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Christian Borntraeger authored
When starting lots of dataplane devices the bootup takes very long on Christian's s390 with irqfd patches. With larger setups he is even able to trigger some timeouts in some components. Turns out that the KVM_SET_GSI_ROUTING ioctl takes very long (strace claims up to 0.1 sec) when having multiple CPUs. This is caused by the synchronize_rcu and the HZ=100 of s390. By changing the code to use a private srcu we can speed things up. This patch reduces the boot time till mounting root from 8 to 2 seconds on my s390 guest with 100 disks. Uses of hlist_for_each_entry_rcu, hlist_add_head_rcu, hlist_del_init_rcu are fine because they do not have lockdep checks (hlist_for_each_entry_rcu uses rcu_dereference_raw rather than rcu_dereference, and write-sides do not do rcu lockdep at all). Note that we're hardly relying on the "sleepable" part of srcu. We just want SRCU's faster detection of grace periods. Testing was done by Andrew Theurer using netperf tests STREAM, MAERTS and RR. The difference between results "before" and "after" the patch has mean -0.2% and standard deviation 0.6%. Using a paired t-test on the data points says that there is a 2.5% probability that the patch is the cause of the performance difference (rather than a random fluctuation). (Restricting the t-test to RR, which is the most likely to be affected, changes the numbers to respectively -0.3% mean, 0.7% stdev, and 8% probability that the numbers actually say something about the patch. The probability increases mostly because there are fewer data points). Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Michael S. Tsirkin <mst@redhat.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> # s390 Reviewed-by:
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- 30 Apr, 2014 1 commit
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Paolo Bonzini authored
Merge tag 'kvm-s390-20140429' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next 1. Guest handling fixes The handling of MVPG, PFMF and Test Block is fixed to better follow the architecture. None of these fixes is critical for any current Linux guests, but let's play safe. 2. Optimization for single CPU guests We can enable the IBS facility if only one VCPU is running (!STOPPED state). We also enable this optimization for guest > 1 VCPU as soon as all but one VCPU is in stopped state. Thus will help guests that have tools like cpuplugd (from s390-utils) that do dynamic offline/ online of CPUs. 3. NOTES There is one non-s390 change in include/linux/kvm_host.h that introduces 2 defines for VCPU requests: define KVM_REQ_ENABLE_IBS 23 define KVM_REQ_DISABLE_IBS 24
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- 29 Apr, 2014 7 commits
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Marcelo Tosatti authored
Invariant TSC is a property of TSC, no additional support code necessary. Signed-off-by:
Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
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David Hildenbrand authored
This patch enables the IBS facility when a single VCPU is running. The facility is dynamically turned on/off as soon as other VCPUs enter/leave the stopped state. When this facility is operating, some instructions can be executed faster for single-cpu guests. Signed-off-by:
Dominik Dingel <dingel@linux.vnet.ibm.com> Reviewed-by:
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David Hildenbrand authored
This patch introduces two new functions to set/clear the CPUSTAT_STOPPED bit and makes use of it at all applicable places. These functions prepare the additional execution of code when starting/stopping a vcpu. The CPUSTAT_STOPPED bit should not be touched outside of these functions. Signed-off-by:
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Thomas Huth authored
TEST BLOCK is also subject to the low-address protection, so we need to check the destination address in our handler. Signed-off-by:
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Thomas Huth authored
Add a check for low-address protection to the PFMF handler and convert real-addresses to absolute if necessary, as it is defined in the Principles of Operations specification. Signed-off-by:
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Thomas Huth authored
The s390 architecture has a special protection mechanism that can be used to prevent write access to the vital data in the low-core memory area. This patch adds a new helper function that can be used to check for such write accesses and in case of protection, it also sets up the exception data accordingly. Signed-off-by:
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Thomas Huth authored
When the guest executes the MVPG instruction with DAT disabled, and the source or destination page is not mapped in the host, the so-called partial execution interception occurs. We need to handle this event by setting up a mapping for the corresponding user pages. Signed-off-by:
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- 28 Apr, 2014 2 commits
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Oleg Nesterov authored
async_pf_execute() passes tsk == current to gup(), this is doesn't hurt but unnecessary and misleading. "tsk" is only used to account the number of faults and current is the random workqueue thread. Signed-off-by:
Oleg Nesterov <oleg@redhat.com> Suggested-by:
Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Oleg Nesterov authored
async_pf_execute() has no reasons to adopt apf->mm, gup(current, mm) should work just fine even if current has another or NULL ->mm. Recently kvm_async_page_present_sync() was added insedie the "use_mm" section, but it seems that it doesn't need current->mm too. Signed-off-by:
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- 23 Apr, 2014 2 commits
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Xiao Guangrong authored
Now we can flush all the TLBs out of the mmu lock without TLB corruption when write-proect the sptes, it is because: - we have marked large sptes readonly instead of dropping them that means we just change the spte from writable to readonly so that we only need to care the case of changing spte from present to present (changing the spte from present to nonpresent will flush all the TLBs immediately), in other words, the only case we need to care is mmu_spte_update() - in mmu_spte_update(), we haved checked SPTE_HOST_WRITEABLE | PTE_MMU_WRITEABLE instead of PT_WRITABLE_MASK, that means it does not depend on PT_WRITABLE_MASK anymore Acked-by:
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Xiao Guangrong authored
Relax the tlb flush condition since we will write-protect the spte out of mmu lock. Note lockless write-protection only marks the writable spte to readonly and the spte can be writable only if both SPTE_HOST_WRITEABLE and SPTE_MMU_WRITEABLE are set (that are tested by spte_is_locklessly_modifiable) This patch is used to avoid this kind of race: VCPU 0 VCPU 1 lockless wirte protection: set spte.w = 0 lock mmu-lock write protection the spte to sync shadow page, see spte.w = 0, then without flush tlb unlock mmu-lock !!! At this point, the shadow page can still be writable due to the corrupt tlb entry Flush all TLB Reviewed-by:
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