- 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:
Paolo Bonzini <pbonzini@redhat.com>
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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:
Thomas Huth <thuth@linux.vnet.ibm.com> Reviewed-by:
David Hildenbrand <dahi@linux.vnet.ibm.com> Reviewed-by:
Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com>
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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 9 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: -
Xiao Guangrong authored
Currently, kvm zaps the large spte if write-protected is needed, the later read can fault on that spte. Actually, we can make the large spte readonly instead of making them un-present, the page fault caused by read access can be avoided The idea is from Avi: | As I mentioned before, write-protecting a large spte is a good idea, | since it moves some work from protect-time to fault-time, so it reduces | jitter. This removes the need for the return value. This version has fixed the issue reported in 6b73a960, the reason of that issue is that fast_page_fault() directly sets the readonly large spte to writable but only dirty the first page into the dirty-bitmap that means other pages are missed. Fixed it by only the normal sptes (on the PT_PAGE_TABLE_LEVEL level) can be fast fixed Reviewed-by:
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Xiao Guangrong authored
Using sp->role.level instead of @level since @level is not got from the page table hierarchy There is no issue in current code since the fast page fault currently only fixes the fault caused by dirty-log that is always on the last level (level = 1) This patch makes the code more readable and avoids potential issue in the further development Reviewed-by:
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Xiao Guangrong authored
This reverts commit 5befdc38. Since we will allow flush tlb out of mmu-lock in the later patch Signed-off-by:
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Nadav Amit authored
If EFER.LMA is off, cs.l does not determine execution mode. Currently, the emulation engine assumes differently. Signed-off-by:
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Nadav Amit authored
The IN instruction is not be affected by REP-prefix as INS is. Therefore, the emulation should ignore the REP prefix as well. The current emulator implementation tries to perform writeback when IN instruction with REP-prefix is emulated. This causes it to perform wrong memory write or spurious #GP exception to be injected to the guest. Signed-off-by:
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Nadav Amit authored
According to Intel specifications, PAE and non-PAE does not have any reserved bits. In long-mode, regardless to PCIDE, only the high bits (above the physical address) are reserved. Signed-off-by:
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Nadav Amit authored
If a guest enables a performance counter but does not enable PMI, the hypervisor currently does not reprogram the performance counter once it overflows. As a result the host performance counter is kept with the original sampling period which was configured according to the value of the guest's counter when the counter was enabled. Such behaviour can cause very bad consequences. The most distrubing one can cause the guest not to make any progress at all, and keep exiting due to host PMI before any guest instructions is exeucted. This situation occurs when the performance counter holds a very high value when the guest enables the performance counter. As a result the host's sampling period is configured to be very short. The host then never reconfigures the sampling period and get stuck at entry->PMI->exit loop. We encountered such a scenario in our experiments. The solution is to reprogram the counter even if the guest does not use PMI. Signed-off-by:
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- 22 Apr, 2014 7 commits
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Bandan Das authored
Some Type 1 hypervisors such as XEN won't enable VMX without it present Signed-off-by:
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Bandan Das authored
This feature emulates the "Acknowledge interrupt on exit" behavior. We can safely emulate it for L1 to run L2 even if L0 itself has it disabled (to run L1). Signed-off-by:
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Bandan Das authored
For single context invalidation, we fall through to global invalidation in handle_invept() except for one case - when the operand supplied by L1 is different from what we have in vmcs12. However, typically hypervisors will only call invept for the currently loaded eptp, so the condition will never be true. Signed-off-by:
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Huw Davies authored
When entering an exception after an ICEBP, the saved instruction pointer should point to after the instruction. This fixes the bug here: https://bugs.launchpad.net/qemu/+bug/1119686Signed-off-by:
Huw Davies <huw@codeweavers.com> Reviewed-by:
Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:
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Marcelo Tosatti authored
Merge tag 'kvm-s390-20140422' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into queue Lazy storage key handling ------------------------- Linux does not use the ACC and F bits of the storage key. Newer Linux versions also do not use the storage keys for dirty and reference tracking. We can optimize the guest handling for those guests for faults as well as page-in and page-out by simply not caring about the guest visible storage key. We trap guest storage key instruction to enable those keys only on demand. Migration bitmap Until now s390 never provided a proper dirty bitmap. Let's provide a proper migration bitmap for s390. We also change the user dirty tracking to a fault based mechanism. This makes the host completely independent from the storage keys. Long term this will allow us to back guest memory with large pages. per-VM device attributes ------------------------ To avoid the introduction of new ioctls, let's provide the attribute semanantic also on the VM-"device". Userspace controlled CMMA ------------------------- The CMMA assist is changed from "always on" to "on if requested" via per-VM device attributes. In addition a callback to reset all usage states is provided. Proper guest DAT handling for intercepts ---------------------------------------- While instructions handled by SIE take care of all addressing aspects, KVM/s390 currently does not care about guest address translation of intercepts. This worked out fine, because - the s390 Linux kernel has a 1:1 mapping between kernel virtual<->real for all pages up to memory size - intercepts happen only for a small amount of cases - all of these intercepts happen to be in the kernel text for current distros Of course we need to be better for other intercepts, kernel modules etc. We provide the infrastructure and rework all in-kernel intercepts to work on logical addresses (paging etc) instead of real ones. The code has been running internally for several months now, so it is time for going public. GDB support ----------- We provide breakpoints, single stepping and watchpoints. Fixes/Cleanups -------------- - Improve program check delivery - Factor out the handling of transactional memory on program checks - Use the existing define __LC_PGM_TDB - Several cleanups in the lowcore structure - Documentation NOTES ----- - All patches touching base s390 are either ACKed or written by the s390 maintainers - One base KVM patch "KVM: add kvm_is_error_gpa() helper" - One patch introduces the notion of VM device attributes Signed-off-by:
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Michael Mueller authored
Factor out the new function handle_itdb(), which copies the ITDB into guest lowcore to fully handle a TX abort. Signed-off-by:
Michael Mueller <mimu@linux.vnet.ibm.com> Acked-by:
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Michael Mueller authored
The generically assembled low core labels already contain the address for the TDB. Signed-off-by:
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