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2011-01-12KVM: Clean up vm creation and releaseJan Kiszka1-17/+6
IA64 support forces us to abstract the allocation of the kvm structure. But instead of mixing this up with arch-specific initialization and doing the same on destruction, split both steps. This allows to move generic destruction calls into generic code. It also fixes error clean-up on failures of kvm_create_vm for IA64. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-25[S390] cleanup facility list handlingMartin Schwidefsky1-1/+1
Store the facility list once at system startup with stfl/stfle and reuse the result for all facility tests. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-25[S390] kvm: Enable z196 instruction facilitiesChristian Borntraeger1-1/+1
Enable PFPO, floating point extension, distinct-operands, fast-BCR-serialization, high-word, interlocked-access, load/store- on-condition, and population-count facilities for guests. (bits 37, 44 and 45). Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-08-01KVM: Remove memory alias supportAvi Kivity1-5/+0
As advertised in feature-removal-schedule.txt. Equivalent support is provided by overlapping memory regions. Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01KVM: s390: Don't exit SIE on SIGP sense runningChristian Borntraeger1-1/+3
Newer (guest) kernels use sigp sense running in their spinlock implementation to check if the other cpu is running before yielding the processor. This revealed some wrong guest settings, causing unnecessary exits for every sigp sense running. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01KVM: s390: Fix build failure due to centralized vcpu locking patchesChristian Borntraeger1-1/+1
This patch fixes ERROR: "__kvm_s390_vcpu_store_status" [arch/s390/kvm/kvm.ko] undefined! triggered by commit 3268c56840dcee78c3e928336550f4e1861504c4 (kvm.git) Author: Avi Kivity <avi@redhat.com> Date: Thu May 13 12:21:46 2010 +0300 KVM: s390: Centrally lock arch specific vcpu ioctls Reported-by: Sachin Sant <sachinp@in.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01KVM: Consolidate arch specific vcpu ioctl lockingAvi Kivity1-7/+6
Now that all arch specific ioctls have centralized locking, it is easy to move it to the central dispatcher. Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01KVM: s390: Centrally lock arch specific vcpu ioctlsAvi Kivity1-23/+17
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01KVM: move vcpu locking to dispatcher for generic vcpu ioctlsAvi Kivity1-16/+0
All vcpu ioctls need to be locked, so instead of locking each one specifically we lock at the generic dispatcher. This patch only updates generic ioctls and leaves arch specific ioctls alone. Signed-off-by: Avi Kivity <avi@redhat.com>
2010-06-08[S390] appldata/extmem/kvm: add missing GFP_KERNEL flagHeiko Carstens1-1/+1
Add missing GFP flag to memory allocations. The part in cio only changes a comment. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-05-19KVM: Let vcpu structure alignment be determined at runtimeAvi Kivity1-1/+1
vmx and svm vcpus have different contents and therefore may have different alignmment requirements. Let each specify its required alignment. Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: s390: Fix possible memory leak of in kvm_arch_vcpu_create()Wei Yongjun1-1/+3
This patch fixed possible memory leak in kvm_arch_vcpu_create() under s390, which would happen when kvm_arch_vcpu_create() fails. Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Acked-by: Carsten Otte <cotte@de.ibm.com> Cc: stable@kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
2010-03-01KVM: fix cleanup_srcu_struct on vm destructionMarcelo Tosatti1-0/+1
cleanup_srcu_struct on VM destruction remains broken: BUG: unable to handle kernel paging request at ffffffffffffffff IP: [<ffffffff802533d2>] srcu_read_lock+0x16/0x21 RIP: 0010:[<ffffffff802533d2>] [<ffffffff802533d2>] srcu_read_lock+0x16/0x21 Call Trace: [<ffffffffa05354c4>] kvm_arch_vcpu_uninit+0x1b/0x48 [kvm] [<ffffffffa05339c6>] kvm_vcpu_uninit+0x9/0x15 [kvm] [<ffffffffa0569f7d>] vmx_free_vcpu+0x7f/0x8f [kvm_intel] [<ffffffffa05357b5>] kvm_arch_destroy_vm+0x78/0x111 [kvm] [<ffffffffa053315b>] kvm_put_kvm+0xd4/0xfe [kvm] Move it to kvm_arch_destroy_vm. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
2010-03-01KVM: split kvm_arch_set_memory_region into prepare and commitMarcelo Tosatti1-9/+16
Required for SRCU convertion later. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-02-26[S390] Cleanup struct _lowcore usage and defines.Heiko Carstens1-0/+1
Use asm offsets to make sure the offset defines to struct _lowcore and its layout don't get out of sync. Also add a BUILD_BUG_ON() which checks that the size of the structure is sane. And while being at it change those sites which use odd casts to access the current lowcore. These should use S390_lowcore instead. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26[S390] Replace ENOTSUPP usage with EOPNOTSUPPHeiko Carstens1-1/+1
ENOTSUPP is not supposed to leak to userspace so lets just use EOPNOTSUPP everywhere. Doesn't fix a bug, but makes future reviews easier. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26[S390] zfcpdump: remove cross arch dump supportHeiko Carstens1-10/+10
Remove support to be able to dump 31 bit systems with a 64 bit dumper. This is mostly useless since no distro ships 31 bit kernels together with a 64 bit dumper. We also get rid of a bit of hacky code. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-03KVM: s390: Make psw available on all exits, not just a subsetCarsten Otte1-8/+17
This patch moves s390 processor status word into the base kvm_run struct and keeps it up-to date on all userspace exits. The userspace ABI is broken by this, however there are no applications in the wild using this. A capability check is provided so users can verify the updated API exists. Cc: stable@kernel.org Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03KVM: Activate Virtualization On DemandAlexander Graf1-1/+2
X86 CPUs need to have some magic happening to enable the virtualization extensions on them. This magic can result in unpleasant results for users, like blocking other VMMs from working (vmx) or using invalid TLB entries (svm). Currently KVM activates virtualization when the respective kernel module is loaded. This blocks us from autoloading KVM modules without breaking other VMMs. To circumvent this problem at least a bit, this patch introduces on demand activation of virtualization. This means, that instead virtualization is enabled on creation of the first virtual machine and disabled on destruction of the last one. So using this, KVM can be easily autoloaded, while keeping other hypervisors usable. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03KVM: Return -ENOTTY on unrecognized ioctlsAvi Kivity1-1/+1
Not the incorrect -EINVAL. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Use macro to iterate over vcpus.Gleb Natapov1-16/+15
[christian: remove unused variables on s390] Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: s390: streamline memslot handlingChristian Ehrhardt1-34/+16
This patch relocates the variables kvm-s390 uses to track guest mem addr/size. As discussed dropping the variables at struct kvm_arch level allows to use the common vcpu->request based mechanism to reload guest memory if e.g. changes via set_memory_region. The kick mechanism introduced in this series is used to ensure running vcpus leave guest state to catch the update. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: s390: fix signal handlingChristian Ehrhardt1-1/+3
If signal pending is true we exit without updating kvm_run, userspace currently just does nothing and jumps to kvm_run again. Since we did not set an exit_reason we might end up with a random one (whatever was the last exit). Therefore it was possible to e.g. jump to the psw position the last real interruption set. Setting the INTR exit reason ensures that no old psw data is swapped in on reentry. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: s390: infrastructure to kick vcpus out of guest stateChristian Ehrhardt1-0/+5
To ensure vcpu's come out of guest context in certain cases this patch adds a s390 specific way to kick them out of guest context. Currently it kicks them out to rerun the vcpu_run path in the s390 code, but the mechanism itself is expandable and with a new flag we could also add e.g. kicks to userspace etc. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-28KVM: s390: Allow stfle instruction in the guestChristian Borntraeger1-1/+22
2.6.31-rc introduced an architecture level set checker based on facility bits. e.g. if the kernel is compiled to run only on z9, several facility bits are checked very early and the kernel refuses to boot if a z9 specific facility is missing. Until now kvm on s390 did not implement the store facility extended (STFLE) instruction. A 2.6.31-rc kernel that was compiled for z9 or higher did not boot in kvm. This patch implements stfle. This patch should go in before 2.6.31. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-12[S390] uaccess: use might_fault() instead of might_sleep()Heiko Carstens1-1/+1
Adds more checking in case lockdep is turned on. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-10KVM: s390: Verify memory in kvm runCarsten Otte1-0/+6
This check verifies that the guest we're trying to run in KVM_RUN has some memory assigned to it. It enters an endless exception loop if this is not the case. Reported-by: Mijo Safradin <mijo@linux.vnet.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: s390: Unlink vcpu on destroy - v2Carsten Otte1-2/+8
This patch makes sure we do unlink a vcpu's sie control block from the system control area in kvm_arch_vcpu_destroy. This prevents illegal accesses to the sie control block from other virtual cpus after free. Reported-by: Mijo Safradin <mijo@linux.vnet.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: s390: optimize float int lock: spin_lock_bh --> spin_lockChristian Borntraeger1-2/+2
The floating interrupt lock is only taken in process context. We can replace all spin_lock_bh with standard spin_lock calls. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: s390: use hrtimer for clock wakeup from idle - v2Christian Borntraeger1-2/+5
This patch reworks the s390 clock comparator wakeup to hrtimer. The clock comparator is a per-cpu value that is compared against the TOD clock. If ckc <= TOD an external interrupt 1004 is triggered. Since the clock comparator and the TOD clock have a much higher resolution than jiffies we should use hrtimers to trigger the wakeup. This speeds up guest nanosleep for small values. Since hrtimers callbacks run in hard-irq context, I added a tasklet to do the actual work with enabled interrupts. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: s390: Fix memory slot versus run - v3Carsten Otte1-5/+31
This patch fixes an incorrectness in the kvm backend for s390. In case virtual cpus are being created before the corresponding memory slot is being registered, we need to update the sie control blocks for the virtual cpus. *updates in v3* In consideration of the s390 memslot constraints locking was changed to trylock. These locks should never be held, as vcpu's can't run without the single memslot we just assign when running this code. To ensure this never deadlocks in case other code changes the code uses trylocks and bail out if it can't get all locks. Additionally most of the discussed special conditions for s390 like only one memslot and no user_alloc are now checked for validity in kvm_arch_set_memory_region. Reported-by: Mijo Safradin <mijo@linux.vnet.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-26Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6Linus Torvalds1-4/+2
* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6: (81 commits) [S390] remove duplicated #includes [S390] cpumask: use mm_cpumask() wrapper [S390] cpumask: Use accessors code. [S390] cpumask: prepare for iterators to only go to nr_cpu_ids/nr_cpumask_bits. [S390] cpumask: remove cpu_coregroup_map [S390] fix clock comparator save area usage [S390] Add hwcap flag for the etf3 enhancement facility [S390] Ensure that ipl panic notifier is called late. [S390] fix dfp elf hwcap/facility bit detection [S390] smp: perform initial cpu reset before starting a cpu [S390] smp: fix memory leak on __cpu_up [S390] ipl: Improve checking logic and remove switch defaults. [S390] s390dbf: Remove needless check for NULL pointer. [S390] s390dbf: Remove redundant initilizations. [S390] use kzfree() [S390] BUG to BUG_ON changes [S390] zfcpdump: Prevent zcore from beeing built as a kernel module. [S390] Use csum_partial in checksum.h [S390] cleanup lowcore.h [S390] eliminate ipl_device from lowcore ...
2009-03-26[S390] split/move machine check handler codeHeiko Carstens1-3/+1
Split machine check handler code and move it to cio and kernel code where it belongs to. No functional change. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26[S390] Fix hypervisor detection for KVMChristian Borntraeger1-1/+1
Currently we use the cpuid (via STIDP instruction) to recognize LPAR, z/VM and KVM. The architecture states, that bit 0-7 of STIDP returns all zero, and if STIDP is executed in a virtual machine, the VM operating system will replace bits 0-7 with FF. KVM should not use FE to distinguish z/VM from KVM for interested guests. The proper way to detect the hypervisor is the STSI (Store System Information) instruction, which return information about the hypervisors via function code 3, selector1=2, selector2=2. This patch changes the detection routine of Linux to use STSI instead of STIDP. This detection is earlier than bootmem, we have to use a static buffer. Since STSI expects a 4kb block (4kb aligned) this patch also changes the init.data alignment for s390. As this section will be freed during boot, this should be no problem. Patch is tested with LPAR, z/VM, KVM on LPAR, and KVM under z/VM. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-24KVM: New guest debug interfaceJan Kiszka1-2/+2
This rips out the support for KVM_DEBUG_GUEST and introduces a new IOCTL instead: KVM_SET_GUEST_DEBUG. The IOCTL payload consists of a generic part, controlling the "main switch" and the single-step feature. The arch specific part adds an x86 interface for intercepting both types of debug exceptions separately and re-injecting them when the host was not interested. Moveover, the foundation for guest debugging via debug registers is layed. To signal breakpoint events properly back to userland, an arch-specific data block is now returned along KVM_EXIT_DEBUG. For x86, the arch block contains the PC, the debug exception, and relevant debug registers to tell debug events properly apart. The availability of this new interface is signaled by KVM_CAP_SET_GUEST_DEBUG. Empty stubs for not yet supported archs are provided. Note that both SVM and VTX are supported, but only the latter was tested yet. Based on the experience with all those VTX corner case, I would be fairly surprised if SVM will work out of the box. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-02-15KVM: Add kvm_arch_sync_events to sync with asynchronize eventsSheng Yang1-0/+4
kvm_arch_sync_events is introduced to quiet down all other events may happen contemporary with VM destroy process, like IRQ handler and work struct for assigned device. For kvm_arch_sync_events is called at the very beginning of kvm_destroy_vm(), so the state of KVM here is legal and can provide a environment to quiet down other events. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31KVM: Consolidate userspace memory capability reporting into common codeAvi Kivity1-2/+0
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31KVM: s390: Fix memory leak of vcpu->runChristian Borntraeger1-2/+2
The s390 backend of kvm never calls kvm_vcpu_uninit. This causes a memory leak of vcpu->run pages. Lets call kvm_vcpu_uninit in kvm_arch_vcpu_destroy to free the vcpu->run. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31KVM: s390: Fix refcounting and allow module unloadChristian Borntraeger1-14/+21
Currently it is impossible to unload the kvm module on s390. This patch fixes kvm_arch_destroy_vm to release all cpus. This make it possible to unload the module. In addition we stop messing with the module refcount in arch code. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2008-07-27KVM: s390: Fix instruction naming for lctlgChristian Borntraeger1-1/+1
Lets fix the name for the lctlg instruction... Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27KVM: s390: Advertise KVM_CAP_USER_MEMORYCarsten Otte1-1/+6
KVM_CAP_USER_MEMORY is used by s390, therefore, we should advertise it. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20KVM: MMU: nuke shadowed pgtable pages and ptes on memslot destructionMarcelo Tosatti1-0/+4
Flush the shadow mmu before removing regions to avoid stale entries. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20KVM: s390: rename private structuresChristian Borntraeger1-1/+2
While doing some tests with our lcrash implementation I have seen a naming conflict with prefix_info in kvm_host.h vs. addrconf.h To avoid future conflicts lets rename private definitions in asm/kvm_host.h by adding the kvm_s390 prefix. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20KVM: s390: Set guest storage limit and offset to sane valuesChristian Borntraeger1-2/+7
Some machines do not accept 16EB as guest storage limit. Lets change the default for the guest storage limit to a sane value. We also should set the guest_origin to what userspace thinks it is. This allows guests starting at an address != 0. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20KVM: Fix memory leak on guest exitCarsten Otte1-0/+1
This patch fixes a memory leak, we want to free the physmem when destroying the vm. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20KVM: Remove decache_vcpus_on_cpu() and related callbacksAvi Kivity1-4/+0
Obsoleted by the vmx-specific per-cpu list. Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-06KVM: s390: Send program check on access errorCarsten Otte1-1/+4
If the guest accesses non-existing memory, the sie64a function returns -EFAULT. We must check the return value and send a program check to the guest if the sie instruction faulted, otherwise the guest will loop at the faulting code. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-06KVM: s390: fix interrupt deliveryCarsten Otte1-1/+2
The current code delivers pending interrupts before it checks for need_resched. On a busy host, this can lead to a longer interrupt latency if the interrupt is injected while the process is scheduled away. This patch moves delivering the interrupt _after_ schedule(), which makes more sense. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-06KVM: s390: handle machine checks when guest is runningChristian Borntraeger1-0/+5
The low-level interrupt handler on s390 checks for _TIF_WORK_INT and exits the guest context, if work is pending. TIF_WORK_INT is defined as_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING. Currently the sie loop checks for signals and reschedule, but it does not check for machine checks. That means that we exit the guest context if a machine check is pending, but we do not handle the machine check. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> CC: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-05-07[S390] s390-kvm: leave sie context on work. Removes preemption requirementChristian Borntraeger1-4/+1
From: Martin Schwidefsky <schwidefsky@de.ibm.com> This patch fixes a bug with cpu bound guest on kvm-s390. Sometimes it was impossible to deliver a signal to a spinning guest. We used preemption as a circumvention. The preemption notifiers called vcpu_load, which checked for pending signals and triggered a host intercept. But even with preemption, a sigkill was not delivered immediately. This patch changes the low level host interrupt handler to check for the SIE instruction, if TIF_WORK is set. In that case we change the instruction pointer of the return PSW to rerun the vcpu_run loop. The kvm code sees an intercept reason 0 if that happens. This patch adds accounting for these types of intercept as well. The advantages: - works with and without preemption - signals are delivered immediately - much better host latencies without preemption Acked-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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