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| * | KVM: s390: protect VCPU cpu timer with a seqcountDavid Hildenbrand2016-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For now, only the owning VCPU thread (that has loaded the VCPU) can get a consistent cpu timer value when calculating the delta. However, other threads might also be interested in a more recent, consistent value. Of special interest will be the timer callback of a VCPU that executes without having the VCPU loaded and could run in parallel with the VCPU thread. The cpu timer has a nice property: it is only updated by the owning VCPU thread. And speaking about accounting, a consistent value can only be calculated by looking at cputm_start and the cpu timer itself in one shot, otherwise the result might be wrong. As we only have one writing thread at a time (owning VCPU thread), we can use a seqcount instead of a seqlock and retry if the VCPU refreshed its cpu timer. This avoids any heavy locking and only introduces a counter update/check plus a handful of smp_wmb(). The owning VCPU thread should never have to retry on reads, and also for other threads this might be a very rare scenario. Please note that we have to use the raw_* variants for locking the seqcount as lockdep will produce false warnings otherwise. The rq->lock held during vcpu_load/put is also acquired from hardirq context. Lockdep cannot know that we avoid potential deadlocks by disabling preemption and thereby disable concurrent write locking attempts (via vcpu_put/load). Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: step VCPU cpu timer during kvm_run ioctlDavid Hildenbrand2016-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Architecturally we should only provide steal time if we are scheduled away, and not if the host interprets a guest exit. We have to step the guest CPU timer in these cases. In the first shot, we will step the VCPU timer only during the kvm_run ioctl. Therefore all time spent e.g. in interception handlers or on irq delivery will be accounted for that VCPU. We have to take care of a few special cases: - Other VCPUs can test for pending irqs. We can only report a consistent value for the VCPU thread itself when adding the delta. - We have to take care of STP sync, therefore we have to extend kvm_clock_sync() and disable preemption accordingly - During any call to disable/enable/start/stop we could get premeempted and therefore get start/stop calls. Therefore we have to make sure we don't get into an inconsistent state. Whenever a VCPU is scheduled out, sleeping, in user space or just about to enter the SIE, the guest cpu timer isn't stepped. Please note that all primitives are prepared to be called from both environments (cpu timer accounting enabled or not), although not completely used in this patch yet (e.g. kvm_s390_set_cpu_timer() will never be called while cpu timer accounting is enabled). Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: abstract access to the VCPU cpu timerDavid Hildenbrand2016-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | We want to manually step the cpu timer in certain scenarios in the future. Let's abstract any access to the cpu timer, so we can hide the complexity internally. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: store cpu id in vcpu->cpu when scheduled inDavid Hildenbrand2016-03-08
| | | | | | | | | | | | | | | | | | | | | | | | By storing the cpu id, we have a way to verify if the current cpu is owning a VCPU. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: bail out early on fatal signal in dirty loggingChristian Borntraeger2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A KVM_GET_DIRTY_LOG ioctl might take a long time. This can result in fatal signals seemingly being ignored. Lets bail out during the dirty bit sync, if a fatal signal is pending. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: do not block CPU on dirty loggingChristian Borntraeger2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When doing dirty logging on huge guests (e.g.600GB) we sometimes get rcu stall timeouts with backtraces like [ 2753.194083] ([<0000000000112fb2>] show_trace+0x12a/0x130) [ 2753.194092] [<0000000000113024>] show_stack+0x6c/0xe8 [ 2753.194094] [<00000000001ee6a8>] rcu_pending+0x358/0xa48 [ 2753.194099] [<00000000001f20cc>] rcu_check_callbacks+0x84/0x168 [ 2753.194102] [<0000000000167654>] update_process_times+0x54/0x80 [ 2753.194107] [<00000000001bdb5c>] tick_sched_handle.isra.16+0x4c/0x60 [ 2753.194113] [<00000000001bdbd8>] tick_sched_timer+0x68/0x90 [ 2753.194115] [<0000000000182a88>] __run_hrtimer+0x88/0x1f8 [ 2753.194119] [<00000000001838ba>] hrtimer_interrupt+0x122/0x2b0 [ 2753.194121] [<000000000010d034>] do_extint+0x16c/0x170 [ 2753.194123] [<00000000005e206e>] ext_skip+0x38/0x3e [ 2753.194129] [<000000000012157c>] gmap_test_and_clear_dirty+0xcc/0x118 [ 2753.194134] ([<00000000001214ea>] gmap_test_and_clear_dirty+0x3a/0x118) [ 2753.194137] [<0000000000132da4>] kvm_vm_ioctl_get_dirty_log+0xd4/0x1b0 [ 2753.194143] [<000000000012ac12>] kvm_vm_ioctl+0x21a/0x548 [ 2753.194146] [<00000000002b57f6>] do_vfs_ioctl+0x30e/0x518 [ 2753.194149] [<00000000002b5a9c>] SyS_ioctl+0x9c/0xb0 [ 2753.194151] [<00000000005e1ae6>] sysc_tracego+0x14/0x1a [ 2753.194153] [<000003ffb75f3972>] 0x3ffb75f3972 We should do a cond_resched in here. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: do not take mmap_sem on dirty log queryChristian Borntraeger2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dirty log query can take a long time for huge guests. Holding the mmap_sem for very long times can cause some unwanted latencies. Turns out that we do not need to hold the mmap semaphore. We hold the slots_lock for gfn->hva translation and walk the page tables with that address, so no need to look at the VMAs. KVM also holds a reference to the mm, which should prevent other things going away. During the walk we take the necessary ptl locks. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: instruction-fetching exceptions on SIE faultsDavid Hildenbrand2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On instruction-fetch exceptions, we have to forward the PSW by any valid ilc and correctly use that ilc when injecting the irq. Injection will already take care of rewinding the PSW if we injected a nullifying program irq, so we don't need special handling prior to injection. Until now, autodetection would have guessed an ilc of 0. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: provide prog irq ilc on SIE faultsDavid Hildenbrand2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On SIE faults, the ilc cannot be detected automatically, as the icptcode is 0. The ilc indicated in the program irq will always be 0. Therefore we have to manually specify the ilc in order to tell the guest which ilen was used when forwarding the PSW. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: read the correct opcode on SIE faultsDavid Hildenbrand2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | Let's use our fresh new function read_guest_instr() to access guest storage via the correct addressing schema. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: gaccess: introduce access modesDavid Hildenbrand2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We will need special handling when fetching instructions, so let's introduce new guest access modes GACC_FETCH and GACC_STORE instead of a write flag. An additional patch will then introduce GACC_IFETCH. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: PSW forwarding / rewinding / ilc reworkDavid Hildenbrand2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have some confusion about ilc vs. ilen in our current code. So let's correctly use the term ilen when dealing with (ilc << 1). Program irq injection didn't take care of the correct ilc in case of irqs triggered by EXECUTE functions, let's provide one function kvm_s390_get_ilen() to take care of all that. Also, manually specifying in intercept handlers the size of the instruction (and sometimes overwriting that value for EXECUTE internally) doesn't make too much sense. So also provide the functions: - kvm_s390_retry_instr to retry the currently intercepted instruction - kvm_s390_rewind_psw to rewind the PSW without internal overwrites - kvm_s390_forward_psw to forward the PSW Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: sync of fp registers via kvm_runDavid Hildenbrand2016-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As we already store the floating point registers in the vector save area in floating point register format when we don't have MACHINE_HAS_VX, we can directly expose them to user space using a new sync flag. The floating point registers will be valid when KVM_SYNC_FPRS is set. The fpc will also be valid when KVM_SYNC_FPRS is set. Either KVM_SYNC_FPRS or KVM_SYNC_VRS will be enabled, never both. Let's also change two positions where we access vrs, making the code easier to read and one comment superfluous. Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: allow sync of fp registers via vregsDavid Hildenbrand2016-02-10
| |/ | | | | | | | | | | | | | | | | | | | | | | | | If we have MACHINE_HAS_VX, the floating point registers are stored in the vector register format, event if the guest isn't enabled for vector registers. So we can allow KVM_SYNC_VRS as soon as MACHINE_HAS_VX is available. This can in return be used by user space to support floating point registers via struct kvm_run when the machine has vector registers. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* / KVM: s390: correct fprs on SIGP (STOP AND) STORE STATUSDavid Hildenbrand2016-03-08
|/ | | | | | | | | | | | | | | | | | | | | | With MACHINE_HAS_VX, we convert the floating point registers from the vector registeres when storing the status. For other VCPUs, these are stored to vcpu->run->s.regs.vrs, but we are using current->thread.fpu.vxrs, which resolves to the currently loaded VCPU. So kvm_s390_store_status_unloaded() currently writes the wrong floating point registers (converted from the vector registers) when called from another VCPU on a z13. This is only the case for old user space not handling SIGP STORE STATUS and SIGP STOP AND STORE STATUS, but relying on the kernel implementation. All other calls come from the loaded VCPU via kvm_s390_store_status(). Fixes: 9abc2a08a7d6 (KVM: s390: fix memory overwrites when vx is disabled) Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: s390: fix memory overwrites when vx is disabledDavid Hildenbrand2016-01-26
| | | | | | | | | | | | | | | | | | | | | | | | | | The kernel now always uses vector registers when available, however KVM has special logic if support is really enabled for a guest. If support is disabled, guest_fpregs.fregs will only contain memory for the fpu. The kernel, however, will store vector registers into that area, resulting in crazy memory overwrites. Simply extending that area is not enough, because the format of the registers also changes. We would have to do additional conversions, making the code even more complex. Therefore let's directly use one place for the vector/fpu registers + fpc (in kvm_run). We just have to convert the data properly when accessing it. This makes current code much easier. Please note that vector/fpu registers are now always stored to vcpu->run->s.regs.vrs. Although this data is visible to QEMU and used for migration, we only guarantee valid values to user space when KVM_SYNC_VRS is set. As that is only the case when we have vector register support, we are on the safe side. Fixes: b5510d9b68c3 ("s390/fpu: always enable the vector facility if it is available") Cc: stable@vger.kernel.org # v4.4 d9a3a09af54d s390/kvm: remove dependency on struct save_area definition Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> [adopt to d9a3a09af54d]
* KVM: s390: fix guest fprs memory leakDavid Hildenbrand2016-01-26
| | | | | | | | | | | | fprs is never freed, therefore resulting in a memory leak if kvm_vcpu_init() fails or the vcpu is destroyed. Fixes: 9977e886cbbc ("s390/kernel: lazy restore fpu registers") Cc: stable@vger.kernel.org # v4.3+ Reported-by: Eric Farman <farman@linux.vnet.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2016-01-13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Martin Schwidefsky: "Among the traditional bug fixes and cleanups are some improvements: - A tool to generated the facility lists, generating the bit fields by hand has been a source of bugs in the past - The spinlock loop is reordered to avoid bursts of hypervisor calls - Add support for the open-for-business interface to the service element - The get_cpu call is added to the vdso - A set of tracepoints is defined for the common I/O layer - The deprecated sclp_cpi module is removed - Update default configuration" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (56 commits) s390/sclp: fix possible control register corruption s390: fix normalization bug in exception table sorting s390/configs: update default configurations s390/vdso: optimize getcpu system call s390: drop smp_mb in vdso_init s390: rename struct _lowcore to struct lowcore s390/mem_detect: use unsigned longs s390/ptrace: get rid of long longs in psw_bits s390/sysinfo: add missing SYSIB 1.2.2 multithreading fields s390: get rid of CONFIG_SCHED_MC and CONFIG_SCHED_BOOK s390/Kconfig: remove pointless 64 bit dependencies s390/dasd: fix failfast for disconnected devices s390/con3270: testing return kzalloc retval s390/hmcdrv: constify hmcdrv_ftp_ops structs s390/cio: add NULL test s390/cio: Change I/O instructions from inline to normal functions s390/cio: Introduce common I/O layer tracepoints s390/cio: Consolidate inline assemblies and related data definitions s390/cio: Fix incorrect xsch opcode specification s390/cio: Remove unused inline assemblies ...
| * s390/kvm: remove dependency on struct save_area definitionMartin Schwidefsky2015-11-27
| | | | | | | | | | | | | | Replace the offsets based on the struct area_area with the offset constants from asm-offsets.c based on the struct _lowcore. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | KVM: s390: implement the RI support of guestFan Zhang2016-01-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds runtime instrumentation support for KVM guest. We need to setup a save area for the runtime instrumentation-controls control block(RICCB) and implement the necessary interfaces to live migrate the guest settings. We setup the sie control block in a way, that the runtime instrumentation instructions of a guest are handled by hardware. We also add a capability KVM_CAP_S390_RI to make this feature opt-in as it needs migration support. Signed-off-by: Fan Zhang <zhangfan@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | kvm/s390: drop unpaired smp_mbMichael S. Tsirkin2016-01-07
| | | | | | | | | | | | | | | | | | | | | | smp_mb on vcpu destroy isn't paired with anything, violating pairing rules, and seems to be useless. Drop it. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <1452010811-25486-1-git-send-email-mst@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: consider system MHA for guest storageGuenther Hutzl2015-12-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Verify that the guest maximum storage address is below the MHA (maximum host address) value allowed on the host. Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> [adopt to match recent limit,size changes] Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: fix mismatch between user and in-kernel guest limitDominik Dingel2015-12-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While the userspace interface requests the maximum size the gmap code expects to get a maximum address. This error resulted in bigger page tables than necessary for some guest sizes, e.g. a 2GB guest used 3 levels instead of 2. At the same time we introduce KVM_S390_NO_MEM_LIMIT, which allows in a bright future that a guest spans the complete 64 bit address space. We also switch to TASK_MAX_SIZE for the initial memory size, this is a cosmetic change as the previous size also resulted in a 4 level pagetable creation. Reported-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: obey kptr_restrict in tracesChristian Borntraeger2015-12-15
| | | | | | | | | | | | | | | | | | | | | | The s390dbf and trace events provide a debugfs interface. If kptr_restrict is active, we should not expose kernel pointers. We can fence the debugfs output by using %pK instead of %p. Cc: Kees Cook <keescook@chromium.org> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: use assignment instead of memcpyChristian Borntraeger2015-12-15
| | | | | | | | | | | | | | | | | | Replace two memcpy with proper assignment. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: remove redudant assigment of error codeChristian Borntraeger2015-11-30
| | | | | | | | | | | | | | | | rc already contains -ENOMEM, no need to assign it twice. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
* | KVM: s390: remove pointless test_facility(2) checkHeiko Carstens2015-11-30
| | | | | | | | | | | | | | | | This evaluates always to 'true'. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: don't load kvm without virtualization supportDavid Hildenbrand2015-11-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we don't have support for virtualization (SIE), e.g. when running under a hypervisor not supporting execution of the SIE instruction, we should immediately abort loading the kvm module, as the SIE instruction cannot be enabled dynamically. Currently, the SIE instructions fails with an exception on a non-SIE host, resulting in the guest making no progress, instead of failing hard. Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: don't switch to ESCA for ucontrolDavid Hildenbrand2015-11-30
| | | | | | | | | | | | | | | | | | | | | | | | sca_add_vpcu is not called for ucontrol guests. We must also not apply the sca checking for sca_can_add_vcpu as ucontrol guests do not have to follow the sca limits. As common code already checks that id < KVM_MAX_VCPUS all other data structures are safe as well. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: cleanup sca_add_vcpuDavid Hildenbrand2015-11-30
| | | | | | | | | | | | | | | | Now that we already have kvm and the VCPU id set for the VCPU, we can convert sda_add_vcpu to look much more like sda_del_vcpu. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: always set/clear the SCA sda fieldDavid Hildenbrand2015-11-30
| | | | | | | | | | | | | | | | | | | | Let's always set and clear the sda when enabling/disabling a VCPU. Dealing with sda being set to something else makes no sense anymore as we enable a VCPU in the SCA now after it has been registered at the VM. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: fix SCA related races and double useDavid Hildenbrand2015-11-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If something goes wrong in kvm_arch_vcpu_create, the VCPU has already been added to the sca but will never be removed. Trying to create VCPUs with duplicate ids (e.g. after a failed attempt) is problematic. Also, when creating multiple VCPUs in parallel, we could theoretically forget to set the correct SCA when the switch to ESCA happens just before the VCPU is registered. Let's add the VCPU to the SCA in kvm_arch_vcpu_postcreate, where we can be sure that no duplicate VCPU with the same id is around and the VCPU has already been registered at the VM. We also have to make sure to update ECB at that point. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: we always have a SCADavid Hildenbrand2015-11-30
| | | | | | | | | | | | | | | | | | | | Having no sca can never happen, even when something goes wrong when switching to ESCA. Otherwise we would have a serious bug. Let's remove this superfluous check. Acked-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: Enable up to 248 VCPUs per VMEugene (jno) Dvurechenski2015-11-30
| | | | | | | | | | | | | | | | | | This patch allows s390 to have more than 64 VCPUs for a guest (up to 248 for memory usage considerations), if supported by the underlaying hardware (sclp.has_esca). Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: Introduce switching codeEugene (jno) Dvurechenski2015-11-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds code that performs transparent switch to Extended SCA on addition of 65th VCPU in a VM. Disposal of ESCA is added too. The entier ESCA functionality, however, is still not enabled. The enablement will be provided in a separate patch. This patch also uses read/write lock protection of SCA and its subfields for possible disposal at the BSCA-to-ESCA transition. While only Basic SCA needs such a protection (for the swap), any SCA access is now guarded. Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: Make provisions for ESCA utilizationEugene (jno) Dvurechenski2015-11-30
| | | | | | | | | | | | | | | | | | | | | | This patch updates the routines (sca_*) to provide transparent access to and manipulation on the data for both Basic and Extended SCA in use. The kvm.arch.sca is generalized to (void *) to handle BSCA/ESCA cases. Also the kvm.arch.use_esca flag is provided. The actual functionality is kept the same. Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: Introduce new structuresEugene (jno) Dvurechenski2015-11-30
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds new structures and updates some existing ones to provide the base for Extended SCA functionality. The old sca_* structures were renamed to bsca_* to keep things uniform. The access to fields of SIGP controls were turned into bitfields instead of hardcoded bitmasks. Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: Provide SCA-aware helpers for VCPU add/delEugene (jno) Dvurechenski2015-11-30
| | | | | | | | | | | | | | | | | | This patch provides SCA-aware helpers to create/delete a VCPU. This is to prepare for upcoming introduction of Extended SCA support. Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | KVM: s390: rewrite vcpu_post_run and drop out earlyDavid Hildenbrand2015-11-30
|/ | | | | | | | | | | | | | Let's rewrite this function to better reflect how we actually handle exit_code. By dropping out early we can save a few cycles. This especially speeds up sie exits caused by host irqs. Also, let's move the special -EOPNOTSUPP for intercepts to the place where it belongs and convert it to -EREMOTE. Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* KVM: s390: enable SIMD only when no VCPUs were createdDavid Hildenbrand2015-11-19
| | | | | | | | | | | | | | | | We should never allow to enable/disable any facilities for the guest when other VCPUs were already created. kvm_arch_vcpu_(load|put) relies on SIMD not changing during runtime. If somebody would create and run VCPUs and then decides to enable SIMD, undefined behaviour could be possible (e.g. vector save area not being set up). Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: stable@vger.kernel.org # 4.1+
* Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2015-11-05
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull KVM updates from Paolo Bonzini: "First batch of KVM changes for 4.4. s390: A bunch of fixes and optimizations for interrupt and time handling. PPC: Mostly bug fixes. ARM: No big features, but many small fixes and prerequisites including: - a number of fixes for the arch-timer - introducing proper level-triggered semantics for the arch-timers - a series of patches to synchronously halt a guest (prerequisite for IRQ forwarding) - some tracepoint improvements - a tweak for the EL2 panic handlers - some more VGIC cleanups getting rid of redundant state x86: Quite a few changes: - support for VT-d posted interrupts (i.e. PCI devices can inject interrupts directly into vCPUs). This introduces a new component (in virt/lib/) that connects VFIO and KVM together. The same infrastructure will be used for ARM interrupt forwarding as well. - more Hyper-V features, though the main one Hyper-V synthetic interrupt controller will have to wait for 4.5. These will let KVM expose Hyper-V devices. - nested virtualization now supports VPID (same as PCID but for vCPUs) which makes it quite a bit faster - for future hardware that supports NVDIMM, there is support for clflushopt, clwb, pcommit - support for "split irqchip", i.e. LAPIC in kernel + IOAPIC/PIC/PIT in userspace, which reduces the attack surface of the hypervisor - obligatory smattering of SMM fixes - on the guest side, stable scheduler clock support was rewritten to not require help from the hypervisor" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (123 commits) KVM: VMX: Fix commit which broke PML KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0() KVM: x86: allow RSM from 64-bit mode KVM: VMX: fix SMEP and SMAP without EPT KVM: x86: move kvm_set_irq_inatomic to legacy device assignment KVM: device assignment: remove pointless #ifdefs KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic KVM: x86: zero apic_arb_prio on reset drivers/hv: share Hyper-V SynIC constants with userspace KVM: x86: handle SMBASE as physical address in RSM KVM: x86: add read_phys to x86_emulate_ops KVM: x86: removing unused variable KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configs KVM: arm/arm64: Merge vgic_set_lr() and vgic_sync_lr_elrsr() KVM: arm/arm64: Clean up vgic_retire_lr() and surroundings KVM: arm/arm64: Optimize away redundant LR tracking KVM: s390: use simple switch statement as multiplexer KVM: s390: drop useless newline in debugging data KVM: s390: SCA must not cross page boundaries KVM: arm: Do not indent the arguments of DECLARE_BITMAP ...
| * KVM: s390: drop useless newline in debugging dataChristian Borntraeger2015-10-29
| | | | | | | | | | | | | | | | the s390 debug feature does not need newlines. In fact it will result in empty lines. Get rid of 4 leftovers. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
| * KVM: s390: SCA must not cross page boundariesDavid Hildenbrand2015-10-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We seemed to have missed a few corner cases in commit f6c137ff00a4 ("KVM: s390: randomize sca address"). The SCA has a maximum size of 2112 bytes. By setting the sca_offset to some unlucky numbers, we exceed the page. 0x7c0 (1984) -> Fits exactly 0x7d0 (2000) -> 16 bytes out 0x7e0 (2016) -> 32 bytes out 0x7f0 (2032) -> 48 bytes out One VCPU entry is 32 bytes long. For the last two cases, we actually write data to the other page. 1. The address of the VCPU. 2. Injection/delivery/clearing of SIGP externall calls via SIGP IF. Especially the 2. happens regularly. So this could produce two problems: 1. The guest losing/getting external calls. 2. Random memory overwrites in the host. So this problem happens on every 127 + 128 created VM with 64 VCPUs. Cc: stable@vger.kernel.org # v3.15+ Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * KVM: s390: factor out reading of the guest TOD clockDavid Hildenbrand2015-10-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's factor this out and always use get_tod_clock_fast() when reading the guest TOD. STORE CLOCK FAST does not do serialization and, therefore, might result in some fuzziness between different processors in a way that subsequent calls on different CPUs might have time stamps that are earlier. This semantics is fine though for all KVM use cases. To make it obvious that the new function has STORE CLOCK FAST semantics we name it kvm_s390_get_tod_clock_fast. With this patch, we only have a handful of places were we have to care about STP sync (using preempt_disable() logic). Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * KVM: s390: factor out and fix setting of guest TOD clockDavid Hildenbrand2015-10-13
| | | | | | | | | | | | | | | | | | | | | | Let's move that whole logic into one function. We now always use unsigned values when calculating the epoch (to avoid over/underflow defined). Also, we always have to get all VCPUs out of SIE before doing the update to avoid running differing VCPUs with different TODs. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * KVM: s390: switch to get_tod_clock() and fix STP sync racesDavid Hildenbrand2015-10-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nobody except early.c makes use of store_tod_clock() to handle the cc. So if we would get a cc != 0, we would be in more trouble. Let's replace all users with get_tod_clock(). Returning a cc on an ioctl sounded strange either way. We can now also easily move the get_tod_clock() call into the preempt_disable() section. This is in fact necessary to make the STP sync work as expected. Otherwise the host TOD could change and we would end up with a wrong epoch calculation. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | s390/fpu: always enable the vector facility if it is availableHendrik Brueckner2015-10-14
|/ | | | | | | | | | | | | | | | | If the kernel detects that the s390 hardware supports the vector facility, it is enabled by default at an early stage. To force it off, use the novx kernel parameter. Note that there is a small time window, where the vector facility is enabled before it is forced to be off. With enabling the vector facility by default, the FPU save and restore functions can be improved. They do not longer require to manage expensive control register updates to enable or disable the vector enablement control for particular processes. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* KVM: s390: Replace incorrect atomic_or with atomic_andnotJason J. Herne2015-09-16
| | | | | | | | | | | | | | The offending commit accidentally replaces an atomic_clear with an atomic_or instead of an atomic_andnot in kvm_s390_vcpu_request_handled. The symptom is that kvm guests on s390 hang on startup. This patch simply replaces the incorrect atomic_or with atomic_andnot Fixes: 805de8f43c20 (atomic: Replace atomic_{set,clear}_mask() usage) Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: add halt_attempted_poll to VCPU statsPaolo Bonzini2015-09-16
| | | | | | | | | | | | | | | | | This new statistic can help diagnosing VCPUs that, for any reason, trigger bad behavior of halt_poll_ns autotuning. For example, say halt_poll_ns = 480000, and wakeups are spaced exactly like 479us, 481us, 479us, 481us. Then KVM always fails polling and wastes 10+20+40+80+160+320+480 = 1110 microseconds out of every 479+481+479+481+479+481+479 = 3359 microseconds. The VCPU then is consuming about 30% more CPU than it would use without polling. This would show as an abnormally high number of attempted polling compared to the successful polls. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com< Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge branch 'locking-core-for-linus' of ↵Linus Torvalds2015-09-03
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking and atomic updates from Ingo Molnar: "Main changes in this cycle are: - Extend atomic primitives with coherent logic op primitives (atomic_{or,and,xor}()) and deprecate the old partial APIs (atomic_{set,clear}_mask()) The old ops were incoherent with incompatible signatures across architectures and with incomplete support. Now every architecture supports the primitives consistently (by Peter Zijlstra) - Generic support for 'relaxed atomics': - _acquire/release/relaxed() flavours of xchg(), cmpxchg() and {add,sub}_return() - atomic_read_acquire() - atomic_set_release() This came out of porting qwrlock code to arm64 (by Will Deacon) - Clean up the fragile static_key APIs that were causing repeat bugs, by introducing a new one: DEFINE_STATIC_KEY_TRUE(name); DEFINE_STATIC_KEY_FALSE(name); which define a key of different types with an initial true/false value. Then allow: static_branch_likely() static_branch_unlikely() to take a key of either type and emit the right instruction for the case. To be able to know the 'type' of the static key we encode it in the jump entry (by Peter Zijlstra) - Static key self-tests (by Jason Baron) - qrwlock optimizations (by Waiman Long) - small futex enhancements (by Davidlohr Bueso) - ... and misc other changes" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (63 commits) jump_label/x86: Work around asm build bug on older/backported GCCs locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations locking, include/llist: Use linux/atomic.h instead of asm/cmpxchg.h locking/qrwlock: Make use of _{acquire|release|relaxed}() atomics locking/qrwlock: Implement queue_write_unlock() using smp_store_release() locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t' locking, asm-generic: Rework atomic-long.h to avoid bulk code duplication locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic locking/static_keys: Make verify_keys() static jump label, locking/static_keys: Update docs locking/static_keys: Provide a selftest jump_label: Provide a self-test s390/uaccess, locking/static_keys: employ static_branch_likely() x86, tsc, locking/static_keys: Employ static_branch_likely() locking/static_keys: Add selftest locking/static_keys: Add a new static_key interface locking/static_keys: Rework update logic locking/static_keys: Add static_key_{en,dis}able() helpers ...
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