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2018-12-21kvm: Change offset in kvm_write_guest_offset_cached to unsignedJim Mattson1-1/+2
Since the offset is added directly to the hva from the gfn_to_hva_cache, a negative offset could result in an out of bounds write. The existing BUG_ON only checks for addresses beyond the end of the gfn_to_hva_cache, not for addresses before the start of the gfn_to_hva_cache. Note that all current call sites have non-negative offsets. Fixes: 4ec6e8636256 ("kvm: Introduce kvm_write_guest_offset_cached()") Reported-by: Cfir Cohen <cfir@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Cfir Cohen <cfir@google.com> Reviewed-by: Peter Shier <pshier@google.com> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-12-14kvm: introduce manual dirty log reprotectPaolo Bonzini1-0/+5
There are two problems with KVM_GET_DIRTY_LOG. First, and less important, it can take kvm->mmu_lock for an extended period of time. Second, its user can actually see many false positives in some cases. The latter is due to a benign race like this: 1. KVM_GET_DIRTY_LOG returns a set of dirty pages and write protects them. 2. The guest modifies the pages, causing them to be marked ditry. 3. Userspace actually copies the pages. 4. KVM_GET_DIRTY_LOG returns those pages as dirty again, even though they were not written to since (3). This is especially a problem for large guests, where the time between (1) and (3) can be substantial. This patch introduces a new capability which, when enabled, makes KVM_GET_DIRTY_LOG not write-protect the pages it returns. Instead, userspace has to explicitly clear the dirty log bits just before using the content of the page. The new KVM_CLEAR_DIRTY_LOG ioctl can also operate on a 64-page granularity rather than requiring to sync a full memslot; this way, the mmu_lock is taken for small amounts of time, and only a small amount of time will pass between write protection of pages and the sending of their content. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-12-14kvm: rename last argument to kvm_get_dirty_log_protectPaolo Bonzini1-1/+1
When manual dirty log reprotect will be enabled, kvm_get_dirty_log_protect's pointer argument will always be false on exit, because no TLB flush is needed until the manual re-protection operation. Rename it from "is_dirty" to "flush", which more accurately tells the caller what they have to do with it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-12-14kvm: make KVM_CAP_ENABLE_CAP_VM architecture agnosticPaolo Bonzini1-0/+2
The first such capability to be handled in virt/kvm/ will be manual dirty page reprotection. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-09-20kvm: x86: make kvm_{load|put}_guest_fpu() staticSebastian Andrzej Siewior1-2/+0
The functions kvm_load_guest_fpu() kvm_put_guest_fpu() are only used locally, make them static. This requires also that both functions are moved because they are used before their implementation. Those functions were exported (via EXPORT_SYMBOL) before commit e5bb40251a920 ("KVM: Drop kvm_{load,put}_guest_fpu() exports"). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-22mm, oom: distinguish blockable mode for mmu notifiersMichal Hocko1-2/+2
There are several blockable mmu notifiers which might sleep in mmu_notifier_invalidate_range_start and that is a problem for the oom_reaper because it needs to guarantee a forward progress so it cannot depend on any sleepable locks. Currently we simply back off and mark an oom victim with blockable mmu notifiers as done after a short sleep. That can result in selecting a new oom victim prematurely because the previous one still hasn't torn its memory down yet. We can do much better though. Even if mmu notifiers use sleepable locks there is no reason to automatically assume those locks are held. Moreover majority of notifiers only care about a portion of the address space and there is absolutely zero reason to fail when we are unmapping an unrelated range. Many notifiers do really block and wait for HW which is harder to handle and we have to bail out though. This patch handles the low hanging fruit. __mmu_notifier_invalidate_range_start gets a blockable flag and callbacks are not allowed to sleep if the flag is set to false. This is achieved by using trylock instead of the sleepable lock for most callbacks and continue as long as we do not block down the call chain. I think we can improve that even further because there is a common pattern to do a range lookup first and then do something about that. The first part can be done without a sleeping lock in most cases AFAICS. The oom_reaper end then simply retries if there is at least one notifier which couldn't make any progress in !blockable mode. A retry loop is already implemented to wait for the mmap_sem and this is basically the same thing. The simplest way for driver developers to test this code path is to wrap userspace code which uses these notifiers into a memcg and set the hard limit to hit the oom. This can be done e.g. after the test faults in all the mmu notifier managed memory and set the hard limit to something really small. Then we are looking for a proper process tear down. [akpm@linux-foundation.org: coding style fixes] [akpm@linux-foundation.org: minor code simplification] Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp Reported-by: David Rientjes <rientjes@google.com> Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Dennis Dalessandro <dennis.dalessandro@intel.com> Cc: Sudeep Dutt <sudeep.dutt@intel.com> Cc: Ashutosh Dixit <ashutosh.dixit@intel.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-06KVM: x86: Add tlb remote flush callback in kvm_x86_ops.Tianyu Lan1-0/+7
This patch is to provide a way for platforms to register hv tlb remote flush callback and this helps to optimize operation of tlb flush among vcpus for nested virtualization case. Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06KVM: Switch 'requests' to be 64-bit (explicitly)KarimAllah Ahmed1-5/+5
Switch 'requests' to be explicitly 64-bit and update BUILD_BUG_ON check to use the size of "requests" instead of the hard-coded '32'. That gives us a bit more room again for arch-specific requests as we already ran out of space for x86 due to the hard-coded check. The only exception here is ARM32 as it is still 32-bits. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim KrÄmář <rkrcmar@redhat.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-07-13KVM: s390: a utility function for migrationClaudio Imbrenda1-0/+7
Introduce a utility function that will be used later on for storage attributes migration, and use it in kvm_main.c to replace existing code that does the same thing. Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Message-Id: <1525106005-13931-2-git-send-email-imbrenda@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2018-06-01kvm: Make VM ioctl do valloc for some archsMarc Orr1-0/+5
The kvm struct has been bloating. For example, it's tens of kilo-bytes for x86, which turns out to be a large amount of memory to allocate contiguously via kzalloc. Thus, this patch does the following: 1. Uses architecture-specific routines to allocate the kvm struct via vzalloc for x86. 2. Switches arm to __KVM_HAVE_ARCH_VM_ALLOC so that it can use vzalloc when has_vhe() is true. Other architectures continue to default to kalloc, as they have a dependency on kalloc or have a small-enough struct kvm. Signed-off-by: Marc Orr <marcorr@google.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-06-01kvm: Change return type to vm_fault_tSouptick Joarder1-1/+1
Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. commit 1c8f422059ae ("mm: change return type to vm_fault_t") Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-06-01Merge tag 'kvmarm-for-v4.18' of ↵Paolo Bonzini1-0/+9
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/ARM updates for 4.18 - Lazy context-switching of FPSIMD registers on arm64 - Allow virtual redistributors to be part of two or more MMIO ranges
2018-05-26KVM: introduce kvm_make_vcpus_request_mask() APIVitaly Kuznetsov1-0/+3
Hyper-V style PV TLB flush hypercalls inmplementation will use this API. To avoid memory allocation in CONFIG_CPUMASK_OFFSTACK case add cpumask_var_t argument. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-05-25KVM: arm/arm64: Introduce kvm_arch_vcpu_run_pid_changeChristoffer Dall1-0/+9
KVM/ARM differs from other architectures in having to maintain an additional virtual address space from that of the host and the guest, because we split the execution of KVM across both EL1 and EL2. This results in a need to explicitly map data structures into EL2 (hyp) which are accessed from the hyp code. As we are about to be more clever with our FPSIMD handling on arm64, which stores data in the task struct and uses thread_info flags, we will have to map parts of the currently executing task struct into the EL2 virtual address space. However, we don't want to do this on every KVM_RUN, because it is a fairly expensive operation to walk the page tables, and the common execution mode is to map a single thread to a VCPU. By introducing a hook that architectures can select with HAVE_KVM_VCPU_RUN_PID_CHANGE, we do not introduce overhead for other architectures, but have a simple way to only map the data we need when required for arm64. This patch introduces the framework only, and wires it up in the arm/arm64 KVM common code. No functional change. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-05-11KVM: Extend MAX_IRQ_ROUTES to 4096 for all archsWanpeng Li1-7/+1
Our virtual machines make use of device assignment by configuring 12 NVMe disks for high I/O performance. Each NVMe device has 129 MSI-X Table entries: Capabilities: [50] MSI-X: Enable+ Count=129 Masked-Vector table: BAR=0 offset=00002000 The windows virtual machines fail to boot since they will map the number of MSI-table entries that the NVMe hardware reported to the bus to msi routing table, this will exceed the 1024. This patch extends MAX_IRQ_ROUTES to 4096 for all archs, in the future this might be extended again if needed. Reviewed-by: Cornelia Huck <cohuck@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim KrÄmář <rkrcmar@redhat.com> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Tonny Lu <tonnylu@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-02-24kvm: fix warning for non-x86 buildsSebastian Ott1-0/+3
Fix the following sparse warning by moving the prototype of kvm_arch_mmu_notifier_invalidate_range() to linux/kvm_host.h . CHECK arch/s390/kvm/../../../virt/kvm/kvm_main.c arch/s390/kvm/../../../virt/kvm/kvm_main.c:138:13: warning: symbol 'kvm_arch_mmu_notifier_invalidate_range' was not declared. Should it be static? Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-02-24kvm: fix warning for CONFIG_HAVE_KVM_EVENTFD buildsSebastian Ott1-1/+2
Move the kvm_arch_irq_routing_update() prototype outside of ifdef CONFIG_HAVE_KVM_EVENTFD guards to fix the following sparse warning: arch/s390/kvm/../../../virt/kvm/irqchip.c:171:28: warning: symbol 'kvm_arch_irq_routing_update' was not declared. Should it be static? Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-14KVM: introduce kvm_arch_vcpu_async_ioctlPaolo Bonzini1-0/+12
After the vcpu_load/vcpu_put pushdown, the handling of asynchronous VCPU ioctl is already much clearer in that it is obvious that they bypass vcpu_load and vcpu_put. However, it is still not perfect in that the different state of the VCPU mutex is still hidden in the caller. Separate those ioctls into a new function kvm_arch_vcpu_async_ioctl that returns -ENOIOCTLCMD for more "traditional" synchronous ioctls. Cc: James Hogan <jhogan@kernel.org> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Suggested-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-14KVM: Take vcpu->mutex outside vcpu_loadChristoffer Dall1-1/+1
As we're about to call vcpu_load() from architecture-specific implementations of the KVM vcpu ioctls, but yet we access data structures protected by the vcpu->mutex in the generic code, factor this logic out from vcpu_load(). x86 is the only architecture which calls vcpu_load() outside of the main vcpu ioctl function, and these calls will no longer take the vcpu mutex following this patch. However, with the exception of kvm_arch_vcpu_postcreate (see below), the callers are either in the creation or destruction path of the VCPU, which means there cannot be any concurrent access to the data structure, because the file descriptor is not yet accessible, or is already gone. kvm_arch_vcpu_postcreate makes the newly created vcpu potentially accessible by other in-kernel threads through the kvm->vcpus array, and we therefore take the vcpu mutex in this case directly. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-05x86,kvm: move qemu/guest FPU switching out to vcpu_runRik van Riel1-1/+1
Currently, every time a VCPU is scheduled out, the host kernel will first save the guest FPU/xstate context, then load the qemu userspace FPU context, only to then immediately save the qemu userspace FPU context back to memory. When scheduling in a VCPU, the same extraneous FPU loads and saves are done. This could be avoided by moving from a model where the guest FPU is loaded and stored with preemption disabled, to a model where the qemu userspace FPU is swapped out for the guest FPU context for the duration of the KVM_RUN ioctl. This is done under the VCPU mutex, which is also taken when other tasks inspect the VCPU FPU context, so the code should already be safe for this change. That should come as no surprise, given that s390 already has this optimization. This can fix a bug where KVM calls get_user_pages while owning the FPU, and the file system ends up requesting the FPU again: [258270.527947] __warn+0xcb/0xf0 [258270.527948] warn_slowpath_null+0x1d/0x20 [258270.527951] kernel_fpu_disable+0x3f/0x50 [258270.527953] __kernel_fpu_begin+0x49/0x100 [258270.527955] kernel_fpu_begin+0xe/0x10 [258270.527958] crc32c_pcl_intel_update+0x84/0xb0 [258270.527961] crypto_shash_update+0x3f/0x110 [258270.527968] crc32c+0x63/0x8a [libcrc32c] [258270.527975] dm_bm_checksum+0x1b/0x20 [dm_persistent_data] [258270.527978] node_prepare_for_write+0x44/0x70 [dm_persistent_data] [258270.527985] dm_block_manager_write_callback+0x41/0x50 [dm_persistent_data] [258270.527988] submit_io+0x170/0x1b0 [dm_bufio] [258270.527992] __write_dirty_buffer+0x89/0x90 [dm_bufio] [258270.527994] __make_buffer_clean+0x4f/0x80 [dm_bufio] [258270.527996] __try_evict_buffer+0x42/0x60 [dm_bufio] [258270.527998] dm_bufio_shrink_scan+0xc0/0x130 [dm_bufio] [258270.528002] shrink_slab.part.40+0x1f5/0x420 [258270.528004] shrink_node+0x22c/0x320 [258270.528006] do_try_to_free_pages+0xf5/0x330 [258270.528008] try_to_free_pages+0xe9/0x190 [258270.528009] __alloc_pages_slowpath+0x40f/0xba0 [258270.528011] __alloc_pages_nodemask+0x209/0x260 [258270.528014] alloc_pages_vma+0x1f1/0x250 [258270.528017] do_huge_pmd_anonymous_page+0x123/0x660 [258270.528021] handle_mm_fault+0xfd3/0x1330 [258270.528025] __get_user_pages+0x113/0x640 [258270.528027] get_user_pages+0x4f/0x60 [258270.528063] __gfn_to_pfn_memslot+0x120/0x3f0 [kvm] [258270.528108] try_async_pf+0x66/0x230 [kvm] [258270.528135] tdp_page_fault+0x130/0x280 [kvm] [258270.528149] kvm_mmu_page_fault+0x60/0x120 [kvm] [258270.528158] handle_ept_violation+0x91/0x170 [kvm_intel] [258270.528162] vmx_handle_exit+0x1ca/0x1400 [kvm_intel] No performance changes were detected in quick ping-pong tests on my 4 socket system, which is expected since an FPU+xstate load is on the order of 0.1us, while ping-ponging between CPUs is on the order of 20us, and somewhat noisy. Cc: stable@vger.kernel.org Signed-off-by: Rik van Riel <riel@redhat.com> Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [Fixed a bug where reset_vcpu called put_fpu without preceding load_fpu, which happened inside from KVM_CREATE_VCPU ioctl. - Radim] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-11-27KVM: Let KVM_SET_SIGNAL_MASK work as advertisedJan H. Schönherr1-0/+3
KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that "any unblocked signal received [...] will cause KVM_RUN to return with -EINTR" and that "the signal will only be delivered if not blocked by the original signal mask". This, however, is only true, when the calling task has a signal handler registered for a signal. If not, signal evaluation is short-circuited for SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN returning or the whole process is terminated. Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar to that in do_sigtimedwait() to avoid short-circuiting of signals. Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-11-09KVM: s390: vsie: use common code functions for pinningDavid Hildenbrand1-0/+1
We will not see -ENOMEM (gfn_to_hva() will return KVM_ERR_PTR_BAD_PAGE for all errors). So we can also get rid of special handling in the callers of pin_guest_page() and always assume that it is a g2 error. As also kvm_s390_inject_program_int() should never fail, we can simplify pin_scb(), too. Signed-off-by: David Hildenbrand <david@redhat.com> Message-Id: <20170901151143.22714-1-david@redhat.com> Acked-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2017-08-08KVM: add spinlock optimization frameworkLongpeng(Mike)1-1/+2
If a vcpu exits due to request a user mode spinlock, then the spinlock-holder may be preempted in user mode or kernel mode. (Note that not all architectures trap spin loops in user mode, only AMD x86 and ARM/ARM64 currently do). But if a vcpu exits in kernel mode, then the holder must be preempted in kernel mode, so we should choose a vcpu in kernel mode as a more likely candidate for the lock holder. This introduces kvm_arch_vcpu_in_kernel() to decide whether the vcpu is in kernel-mode when it's preempted. kvm_vcpu_on_spin's new argument says the same of the spinning VCPU. Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-07KVM: nVMX: get rid of nested_get_page()David Hildenbrand1-0/+6
nested_get_page() just sounds confusing. All we want is a page from G1. This is even unrelated to nested. Let's introduce kvm_vcpu_gpa_to_page() so we don't get too lengthy lines. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> [Squash pasto fix from Wanpeng Li. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-02KVM: avoid using rcu_dereference_protectedPaolo Bonzini1-2/+4
During teardown, accesses to memslots and buses are using rcu_dereference_protected with an always-true condition because these accesses are done outside the usual mutexes. This is because the last reference is gone and there cannot be any concurrent modifications, but rcu_dereference_protected is ugly and unobvious. Instead, check the refcount in kvm_get_bus and __kvm_memslots. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-07-26KVM: make pid available for uevents without debugfsClaudio Imbrenda1-0/+1
Simplify and improve the code so that the PID is always available in the uevent even when debugfs is not available. This adds a userspace_pid field to struct kvm, as per Radim's suggestion, so that the PID can be retrieved on destruction too. Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com> Fixes: 286de8f6ac9202 ("KVM: trigger uevents when creating or destroying a VM") Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-07-10KVM: use correct accessor function for __kvm_memslotsChristian Borntraeger1-3/+2
kvm memslots are protected by srcu and not by rcu. We must use srcu_dereference_check instead of rcu_dereference_check. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
2017-07-07KVM: mark memory slots as rcuChristian Borntraeger1-1/+1
we access the memslots array via srcu. Mark it as such and use the right access functions also for the freeing of memory slots. Found by sparse: ./include/linux/kvm_host.h:565:16: error: incompatible types in comparison expression (different address spaces) Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2017-07-07KVM: mark kvm->busses as rcu protectedChristian Borntraeger1-1/+7
mark kvm->busses as rcu protected and use the correct access function everywhere. found by sparse virt/kvm/kvm_main.c:3490:15: error: incompatible types in comparison expression (different address spaces) virt/kvm/kvm_main.c:3509:15: error: incompatible types in comparison expression (different address spaces) virt/kvm/kvm_main.c:3561:15: error: incompatible types in comparison expression (different address spaces) virt/kvm/kvm_main.c:3644:15: error: incompatible types in comparison expression (different address spaces) Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2017-07-07KVM: mark vcpu->pid pointer as rcu protectedChristian Borntraeger1-1/+1
We do use rcu to protect the pid pointer. Mark it as such and adopt all code to use the proper access methods. This was detected by sparse. "virt/kvm/kvm_main.c:2248:15: error: incompatible types in comparison expression (different address spaces)" Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2017-06-04KVM: add kvm_request_pendingRadim Krčmář1-0/+5
A first step in vcpu->requests encapsulation. Additionally, we now use READ_ONCE() when accessing vcpu->requests, which ensures we always load vcpu->requests when it's accessed. This is important as other threads can change it any time. Also, READ_ONCE() documents that vcpu->requests is used with other threads, likely requiring memory barriers, which it does. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> [ Documented the new use of READ_ONCE() and converted another check in arch/mips/kvm/vz.c ] Signed-off-by: Andrew Jones <drjones@redhat.com> Acked-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04KVM: improve arch vcpu request definingAndrew Jones1-0/+7
Marc Zyngier suggested that we define the arch specific VCPU request base, rather than requiring each arch to remember to start from 8. That suggestion, along with Radim Krcmar's recent VCPU request flag addition, snowballed into defining something of an arch VCPU request defining API. No functional change. (Looks like x86 is running out of arch VCPU request bits. Maybe someday we'll need to extend to 64.) Signed-off-by: Andrew Jones <drjones@redhat.com> Acked-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-05-10Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-1/+11
Pull more KVM updates from Paolo Bonzini: "ARM: - bugfixes - moved shared 32-bit/64-bit files to virt/kvm/arm - support for saving/restoring virtual ITS state to userspace PPC: - XIVE (eXternal Interrupt Virtualization Engine) support x86: - nVMX improvements, including emulated page modification logging (PML) which brings nice performance improvements on some workloads" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (45 commits) KVM: arm/arm64: vgic-its: Cleanup after failed ITT restore KVM: arm/arm64: Don't call map_resources when restoring ITS tables KVM: arm/arm64: Register ITS iodev when setting base address KVM: arm/arm64: Get rid of its->initialized field KVM: arm/arm64: Register iodevs when setting redist base and creating VCPUs KVM: arm/arm64: Slightly rework kvm_vgic_addr KVM: arm/arm64: Make vgic_v3_check_base more broadly usable KVM: arm/arm64: Refactor vgic_register_redist_iodevs KVM: Add kvm_vcpu_get_idx to get vcpu index in kvm->vcpus nVMX: Advertise PML to L1 hypervisor nVMX: Implement emulated Page Modification Logging kvm: x86: Add a hook for arch specific dirty logging emulation kvm: nVMX: Validate CR3 target count on nested VM-entry KVM: set no_llseek in stat_fops_per_vm KVM: arm/arm64: vgic: Rename kvm_vgic_vcpu_init to kvm_vgic_vcpu_enable KVM: arm/arm64: Clarification and relaxation to ITS save/restore ABI KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES KVM: arm64: vgic-its: Fix pending table sync KVM: arm64: vgic-its: ITT save and restore KVM: arm64: vgic-its: Device table save/restore ...
2017-05-10Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes are: - Debloat RCU headers - Parallelize SRCU callback handling (plus overlapping patches) - Improve the performance of Tree SRCU on a CPU-hotplug stress test - Documentation updates - Miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits) rcu: Open-code the rcu_cblist_n_lazy_cbs() function rcu: Open-code the rcu_cblist_n_cbs() function rcu: Open-code the rcu_cblist_empty() function rcu: Separately compile large rcu_segcblist functions srcu: Debloat the <linux/rcu_segcblist.h> header srcu: Adjust default auto-expediting holdoff srcu: Specify auto-expedite holdoff time srcu: Expedite first synchronize_srcu() when idle srcu: Expedited grace periods with reduced memory contention srcu: Make rcutorture writer stalls print SRCU GP state srcu: Exact tracking of srcu_data structures containing callbacks srcu: Make SRCU be built by default srcu: Fix Kconfig botch when SRCU not selected rcu: Make non-preemptive schedule be Tasks RCU quiescent state srcu: Expedite srcu_schedule_cbs_snp() callback invocation srcu: Parallelize callback handling kvm: Move srcu_struct fields to end of struct kvm rcu: Fix typo in PER_RCU_NODE_PERIOD header comment rcu: Use true/false in assignment to bool rcu: Use bool value directly ...
2017-05-09Merge tag 'kvm-arm-for-v4.12-round2' of ↵Paolo Bonzini1-0/+11
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD Second round of KVM/ARM Changes for v4.12. Changes include: - A fix related to the 32-bit idmap stub - A fix to the bitmask used to deode the operands of an AArch32 CP instruction - We have moved the files shared between arch/arm/kvm and arch/arm64/kvm to virt/kvm/arm - We add support for saving/restoring the virtual ITS state to userspace
2017-05-09KVM: Add kvm_vcpu_get_idx to get vcpu index in kvm->vcpusChristoffer Dall1-0/+11
There are occasional needs to use the index of vcpu in the kvm->vcpus array to map something related to a VCPU. For example, unlike the vcpu->vcpu_id, the vcpu index is guaranteed to not be sparse across all vcpus which is useful when allocating a memory area for each vcpu. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Eric Auger <eric.auger@redhat.com>
2017-05-09Merge branch 'kvm-ppc-next' of ↵Paolo Bonzini1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD The main thing here is a new implementation of the in-kernel XICS interrupt controller emulation for POWER9 machines, from Ben Herrenschmidt. POWER9 has a new interrupt controller called XIVE (eXternal Interrupt Virtualization Engine) which is able to deliver interrupts directly to guest virtual CPUs in hardware without hypervisor intervention. With this new code, the guest still sees the old XICS interface but performance is better because the XICS emulation in the host uses the XIVE directly rather than going through a XICS emulation in firmware. Conflicts: arch/powerpc/kernel/cpu_setup_power.S [cherry-picked fix] arch/powerpc/kvm/book3s_xive.c [include asm/debugfs.h]
2017-05-09Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-2/+0
Merge more updates from Andrew Morton: - the rest of MM - various misc things - procfs updates - lib/ updates - checkpatch updates - kdump/kexec updates - add kvmalloc helpers, use them - time helper updates for Y2038 issues. We're almost ready to remove current_fs_time() but that awaits a btrfs merge. - add tracepoints to DAX * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits) drivers/staging/ccree/ssi_hash.c: fix build with gcc-4.4.4 selftests/vm: add a test for virtual address range mapping dax: add tracepoint to dax_insert_mapping() dax: add tracepoint to dax_writeback_one() dax: add tracepoints to dax_writeback_mapping_range() dax: add tracepoints to dax_load_hole() dax: add tracepoints to dax_pfn_mkwrite() dax: add tracepoints to dax_iomap_pte_fault() mtd: nand: nandsim: convert to memalloc_noreclaim_*() treewide: convert PF_MEMALLOC manipulations to new helpers mm: introduce memalloc_noreclaim_{save,restore} mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC mm/huge_memory.c: deposit a pgtable for DAX PMD faults when required mm/huge_memory.c: use zap_deposited_table() more time: delete CURRENT_TIME_SEC and CURRENT_TIME gfs2: replace CURRENT_TIME with current_time apparmorfs: replace CURRENT_TIME with current_time() lustre: replace CURRENT_TIME macro fs: ubifs: replace CURRENT_TIME_SEC with current_time fs: ufs: use ktime_get_real_ts64() for birthtime ...
2017-05-09mm: introduce kv[mz]alloc helpersMichal Hocko1-2/+0
Patch series "kvmalloc", v5. There are many open coded kmalloc with vmalloc fallback instances in the tree. Most of them are not careful enough or simply do not care about the underlying semantic of the kmalloc/page allocator which means that a) some vmalloc fallbacks are basically unreachable because the kmalloc part will keep retrying until it succeeds b) the page allocator can invoke a really disruptive steps like the OOM killer to move forward which doesn't sound appropriate when we consider that the vmalloc fallback is available. As it can be seen implementing kvmalloc requires quite an intimate knowledge if the page allocator and the memory reclaim internals which strongly suggests that a helper should be implemented in the memory subsystem proper. Most callers, I could find, have been converted to use the helper instead. This is patch 6. There are some more relying on __GFP_REPEAT in the networking stack which I have converted as well and Eric Dumazet was not opposed [2] to convert them as well. [1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org [2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com This patch (of 9): Using kmalloc with the vmalloc fallback for larger allocations is a common pattern in the kernel code. Yet we do not have any common helper for that and so users have invented their own helpers. Some of them are really creative when doing so. Let's just add kv[mz]alloc and make sure it is implemented properly. This implementation makes sure to not make a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also to not warn about allocation failures. This also rules out the OOM killer as the vmalloc is a more approapriate fallback than a disruptive user visible action. This patch also changes some existing users and removes helpers which are specific for them. In some cases this is not possible (e.g. ext4_kvmalloc, libcfs_kvzalloc) because those seems to be broken and require GFP_NO{FS,IO} context which is not vmalloc compatible in general (note that the page table allocation is GFP_KERNEL). Those need to be fixed separately. While we are at it, document that __vmalloc{_node} about unsupported gfp mask because there seems to be a lot of confusion out there. kvmalloc_node will warn about GFP_KERNEL incompatible (which are not superset) flags to catch new abusers. Existing ones would have to die slowly. [sfr@canb.auug.org.au: f2fs fixup] Link: http://lkml.kernel.org/r/20170320163735.332e64b7@canb.auug.org.au Link: http://lkml.kernel.org/r/20170306103032.2540-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Reviewed-by: Andreas Dilger <adilger@dilger.ca> [ext4 part] Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: John Hubbard <jhubbard@nvidia.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03Revert "KVM: Support vCPU-based gfn->hva cache"Paolo Bonzini1-8/+8
This reverts commit bbd6411513aa8ef3ea02abab61318daf87c1af1e. I've been sitting on this revert for too long and it unfortunately missed 4.11. It's also the reason why I haven't merged ring-based dirty tracking for 4.12. Using kvm_vcpu_memslots in kvm_gfn_to_hva_cache_init and kvm_vcpu_write_guest_offset_cached means that the MSR value can now be used to access SMRAM, simply by making it point to an SMRAM physical address. This is problematic because it lets the guest OS overwrite memory that it shouldn't be able to touch. Cc: stable@vger.kernel.org Fixes: bbd6411513aa8ef3ea02abab61318daf87c1af1e Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-05-02KVM: x86: don't hold kvm->lock in KVM_SET_GSI_ROUTINGDavid Hildenbrand1-0/+1
We needed the lock to avoid racing with creation of the irqchip on x86. As kvm_set_irq_routing() calls srcu_synchronize_expedited(), this lock might be held for a longer time. Let's introduce an arch specific callback to check if we can actually add irq routes. For x86, all we have to do is check if we have an irqchip in the kernel. We don't need kvm->lock at that point as the irqchip is marked as inititalized only when actually fully created. Reported-by: Steve Rutherford <srutherford@google.com> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Fixes: 1df6ddede10a ("KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP") Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-28Merge remote-tracking branch 'remotes/powerpc/topic/xive' into kvm-ppc-nextPaul Mackerras1-1/+0
This merges in the powerpc topic/xive branch to bring in the code for the in-kernel XICS interrupt controller emulation to use the new XIVE (eXternal Interrupt Virtualization Engine) hardware in the POWER9 chip directly, rather than via a XICS emulation in firmware. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-04-27KVM: mark requests that need synchronizationPaolo Bonzini1-4/+5
kvm_make_all_requests() provides a synchronization that waits until all kicked VCPUs have acknowledged the kick. This is important for KVM_REQ_MMU_RELOAD as it prevents freeing while lockless paging is underway. This patch adds the synchronization property into all requests that are currently being used with kvm_make_all_requests() in order to preserve the current behavior and only introduce a new framework. Removing it from requests where it is not necessary is left for future patches. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-27KVM: return if kvm_vcpu_wake_up() did wake up the VCPURadim Krčmář1-1/+1
No need to kick a VCPU that we have just woken up. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-27KVM: add explicit barrier to kvm_vcpu_kickAndrew Jones1-0/+6
kvm_vcpu_kick() must issue a general memory barrier prior to reading vcpu->mode in order to ensure correctness of the mutual-exclusion memory barrier pattern used with vcpu->requests. While the cmpxchg called from kvm_vcpu_kick(): kvm_vcpu_kick kvm_arch_vcpu_should_kick kvm_vcpu_exiting_guest_mode cmpxchg implies general memory barriers before and after the operation, that implication is only valid when cmpxchg succeeds. We need an explicit barrier for when it fails, otherwise a VCPU thread on its entry path that reads zero for vcpu->requests does not exclude the possibility the requesting thread sees !IN_GUEST_MODE when it reads vcpu->mode. kvm_make_all_cpus_request already had a barrier, so we remove it, as now it would be redundant. Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-27KVM: mark requests that do not need a wakeupRadim Krčmář1-5/+7
Some operations must ensure that the guest is not running with stale data, but if the guest is halted, then the update can wait until another event happens. kvm_make_all_requests() currently doesn't wake up, so we can mark all requests used with it. First 8 bits were arbitrarily reserved for request numbers. Most uses of requests have the request type as a constant, so a compiler will optimize the '&'. An alternative would be to have an inline function that would return whether the request needs a wake-up or not, but I like this one better even though it might produce worse assembly. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-27KVM: add kvm_{test,clear}_request to replace {test,clear}_bitRadim Krčmář1-2/+12
Users were expected to use kvm_check_request() for testing and clearing, but request have expanded their use since then and some users want to only test or do a faster clear. Make sure that requests are not directly accessed with bit operations. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-27KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controllerBenjamin Herrenschmidt1-1/+0
This patch makes KVM capable of using the XIVE interrupt controller to provide the standard PAPR "XICS" style hypercalls. It is necessary for proper operations when the host uses XIVE natively. This has been lightly tested on an actual system, including PCI pass-through with a TG3 device. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [mpe: Cleanup pr_xxx(), unsplit pr_xxx() strings, etc., fix build failures by adding KVM_XIVE which depends on KVM_XICS and XIVE, and adding empty stubs for the kvm_xive_xxx() routines, fixup subject, integrate fixes from Paul for building PR=y HV=n] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-23Merge branch 'for-mingo' of ↵Ingo Molnar1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Documentation updates. - Miscellaneous fixes. - Parallelize SRCU callback handling (plus overlapping patches). Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-21kvm: Move srcu_struct fields to end of struct kvmPaul E. McKenney1-2/+2
Parallelizing SRCU callback handling will increase the size of srcu_struct, which will move the kvm structure's kvm_arch field out of reach of powerpc's current assembly code, which will result in the following sort of build error: arch/powerpc/kvm/book3s_hv_rmhandlers.S:617: Error: operand out of range (0x000000000000b328 is not between 0xffffffffffff8000 and 0x0000000000007fff) This commit moves the srcu_struct fields in the kvm structure to follow the kvm_arch field, which will allow powerpc's assembly code to continue to be able to reach the kvm_arch field. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: Michael Ellerman <michaele@au1.ibm.com> Reported-by: kbuild test robot <fengguang.wu@intel.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Paolo Bonzini <pbonzini@redhat.com> [ paulmck: Moved this commit to precede SRCU callback parallelization, and reworded the commit log into future tense, all in the name of bisectability. ]