- 04 Mar, 2016 15 commits
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Radim Krčmář authored
Document possible races between readers and concurrent update to the ioctl. Suggested-by:
Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com> Signed-off-by:
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Radim Krčmář authored
We can do it just once. Reviewed-by:
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Radim Krčmář authored
channels has offset 0 and correct size now, but that can change. Reviewed-by:
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Radim Krčmář authored
PIT is known at that point. Reviewed-by:
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Radim Krčmář authored
kvm isn't ever used and pit can be accessed with container_of. If you *really* need kvm, pit_state_to_pit(ps)->kvm. Reviewed-by:
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Radim Krčmář authored
Could be easier to read, but git history will become deeper. Reviewed-by:
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Radim Krčmář authored
Locks are gone, so we don't need to duplicate error paths. Use goto everywhere. Reviewed-by:
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Radim Krčmář authored
Discard policy doesn't rely on information from notifiers, so we don't need to register notifiers unconditionally. We kept correct counts in case userspace switched between policies during runtime, but that can be avoided by reseting the state. Signed-off-by:
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Radim Krčmář authored
- kvm_create_pit had to lock only because it exposed kvm->arch.vpit very early, but initialization doesn't use kvm->arch.vpit since the last patch, so we can drop locking. - kvm_free_pit is only run after there are no users of KVM and therefore is the sole actor. - Locking in kvm_vm_ioctl_reinject doesn't do anything, because reinject is only protected at that place. - kvm_pit_reset isn't used anywhere and its locking can be dropped if we hide it. Removing useless locking allows to see what actually is being protected by PIT state lock (values accessible from the guest). Signed-off-by:
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Radim Krčmář authored
This patch passes struct kvm_pit into internal PIT functions. Those functions used to get PIT through kvm->arch.vpit, even though most of them never used *kvm for other purposes. Another benefit is that we don't need to set kvm->arch.vpit during initialization. Signed-off-by:
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Radim Krčmář authored
If the guest could hit this, it would hang the host kernel, bacause of sheer number of those reports. Internal callers have to be sensible anyway, so we now only check for it in an API function. Signed-off-by:
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Radim Krčmář authored
The lock was an overkill, the same can be done with atomics. A mb() was added in kvm_pit_ack_irq, to pair with implicit barrier between pit_timer_fn and pit_do_work. The mb() prevents a race that could happen if pending == 0 and irq_ack == 0: kvm_pit_ack_irq: | pit_timer_fn: p = atomic_read(&ps->pending); | | atomic_inc(&ps->pending); | queue_work(pit_do_work); | pit_do_work: | atomic_xchg(&ps->irq_ack, 0); | return; atomic_set(&ps->irq_ack, 1); | if (p == 0) return; | where the interrupt would not be delivered in this tick of pit_timer_fn. PIT would have eventually delivered the interrupt, but we sacrifice perofmance to make sure that interrupts are not needlessly delayed. sfence isn't enough: atomic_dec_if_positive does atomic_read first and x86 can reorder loads before stores. lfence isn't enough: store can pass lfence, turning it into a nop. A compiler barrier would be more than enough as CPU needs to stall for unbelievably long to use fences. This patch doesn't do anything in kvm_pit_reset_reinject, because any order of resets can race, but the result differs by at most one interrupt, which is ok, because it's the same result as if the reset happened at a slightly different time. (Original code didn't protect the reset path with a proper lock, so users have to be robust.) Signed-off-by: -
Radim Krčmář authored
pit_state.pending and pit_state.irq_ack are always reset at the same time. Create a function for them. Signed-off-by:
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Radim Krčmář authored
We already have a helper that does the same thing. Signed-off-by:
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Radim Krčmář authored
Discard policy uses ack_notifiers to prevent injection of PIT interrupts before EOI from the last one. This patch changes the policy to always try to deliver the interrupt, which makes a difference when its vector is in ISR. Old implementation would drop the interrupt, but proposed one injects to IRR, like real hardware would. The old policy breaks legacy NMI watchdogs, where PIT is used through virtual wire (LVT0): PIT never sends an interrupt before receiving EOI, thus a guest deadlock with disabled interrupts will stop NMIs. Note that NMI doesn't do EOI, so PIT also had to send a normal interrupt through IOAPIC. (KVM's PIT is deeply rotten and luckily not used much in modern systems.) Even though there is a chance of regressions, I think we can fix the LVT0 NMI bug without introducing a new tick policy. Cc: <stable@vger.kernel.org> Reported-by:
Yuki Shibuya <shibuya.yk@ncos.nec.co.jp> Reviewed-by:
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- 03 Mar, 2016 15 commits
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Xiao Guangrong authored
Register the notifier to receive write track event so that we can update our shadow page table It makes kvm_mmu_pte_write() be the callback of the notifier, no function is changed Signed-off-by:
Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by:
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Xiao Guangrong authored
Now, all non-leaf shadow page are page tracked, if gfn is not tracked there is no non-leaf shadow page of gfn is existed, we can directly make the shadow page of gfn to unsync Signed-off-by:
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Xiao Guangrong authored
non-leaf shadow pages are always write protected, it can be the user of page track Signed-off-by:
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Xiao Guangrong authored
Notifier list is introduced so that any node wants to receive the track event can register to the list Two APIs are introduced here: - kvm_page_track_register_notifier(): register the notifier to receive track event - kvm_page_track_unregister_notifier(): stop receiving track event by unregister the notifier The callback, node->track_write() is called when a write access on the write tracked page happens Signed-off-by:
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Xiao Guangrong authored
If the page fault is caused by write access on write tracked page, the real shadow page walking is skipped, we lost the chance to clear write flooding for the page structure current vcpu is using Fix it by locklessly waking shadow page table to clear write flooding on the shadow page structure out of mmu-lock. So that we change the count to atomic_t Signed-off-by:
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Xiao Guangrong authored
The page fault caused by write access on the write tracked page can not be fixed, it always need to be emulated. page_fault_handle_page_track() is the fast path we introduce here to skip holding mmu-lock and shadow page table walking However, if the page table is not present, it is worth making the page table entry present and readonly to make the read access happy mmu_need_write_protect() need to be cooked to avoid page becoming writable when making page table present or sync/prefetch shadow page table entries Signed-off-by:
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Xiao Guangrong authored
These two functions are the user APIs: - kvm_slot_page_track_add_page(): add the page to the tracking pool after that later specified access on that page will be tracked - kvm_slot_page_track_remove_page(): remove the page from the tracking pool, the specified access on the page is not tracked after the last user is gone Both of these are called under the protection both of mmu-lock and kvm->srcu or kvm->slots_lock Signed-off-by:
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Xiao Guangrong authored
The array, gfn_track[mode][gfn], is introduced in memory slot for every guest page, this is the tracking count for the gust page on different modes. If the page is tracked then the count is increased, the page is not tracked after the count reaches zero We use 'unsigned short' as the tracking count which should be enough as shadow page table only can use 2^14 (2^3 for level, 2^1 for cr4_pae, 2^2 for quadrant, 2^3 for access, 2^1 for nxe, 2^1 for cr0_wp, 2^1 for smep_andnot_wp, 2^1 for smap_andnot_wp, and 2^1 for smm) at most, there is enough room for other trackers Two callbacks, kvm_page_track_create_memslot() and kvm_page_track_free_memslot() are implemented in this patch, they are internally used to initialize and reclaim the memory of the array Currently, only write track mode is supported Signed-off-by:
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Xiao Guangrong authored
Split rmap_write_protect() and introduce the function to abstract the write protection based on the slot This function will be used in the later patch Reviewed-by:
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Xiao Guangrong authored
Abstract the common operations from account_shadowed() and unaccount_shadowed(), then introduce kvm_mmu_gfn_disallow_lpage() and kvm_mmu_gfn_allow_lpage() These two functions will be used by page tracking in the later patch Reviewed-by:
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Xiao Guangrong authored
kvm_lpage_info->write_count is used to detect if the large page mapping for the gfn on the specified level is allowed, rename it to disallow_lpage to reflect its purpose, also we rename has_wrprotected_page() to mmu_gfn_lpage_is_disallowed() to make the code more clearer Later we will extend this mechanism for page tracking: if the gfn is tracked then large mapping for that gfn on any level is not allowed. The new name is more straightforward Reviewed-by:
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Joerg Roedel authored
Using the vector stored at interrupt delivery makes the eoi matching safe agains irq migration in the ioapic. Signed-off-by:
Joerg Roedel <jroedel@suse.de> Signed-off-by:
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Joerg Roedel authored
This allows backtracking later in case the rtc irq has been moved to another vcpu/vector. Signed-off-by:
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Joerg Roedel authored
Currently this is a bitmap which tracks which CPUs we expect an EOI from. Move this bitmap to a struct so that we can track additional information there. Signed-off-by:
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Paolo Bonzini authored
Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD The highlights are: * Enable VFIO device on PowerPC, from David Gibson * Optimizations to speed up IPIs between vcpus in HV KVM, from Suresh Warrier (who is also Suresh E. Warrier) * In-kernel handling of IOMMU hypercalls, and support for dynamic DMA windows (DDW), from Alexey Kardashevskiy. Signed-off-by:
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- 01 Mar, 2016 4 commits
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Alexey Kardashevskiy authored
The existing KVM_CREATE_SPAPR_TCE only supports 32bit windows which is not enough for directly mapped windows as the guest can get more than 4GB. This adds KVM_CREATE_SPAPR_TCE_64 ioctl and advertises it via KVM_CAP_SPAPR_TCE_64 capability. The table size is checked against the locked memory limit. Since 64bit windows are to support Dynamic DMA windows (DDW), let's add @bus_offset and @page_shift which are also required by DDW. Signed-off-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by:
Paul Mackerras <paulus@samba.org>
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Alexey Kardashevskiy authored
This enables userspace view of TCE tables to start from non-zero offset on a bus. This will be used for huge DMA windows. This only changes the internal structure, the user interface needs to change in order to use an offset. Signed-off-by:
David Gibson <david@gibson.dropbear.id.au> Signed-off-by:
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Alexey Kardashevskiy authored
At the moment the kvmppc_spapr_tce_table struct can only describe 4GB windows and handle fixed size (4K) pages. Dynamic DMA windows support more so these limits need to be extended. This replaces window_size (in bytes, 4GB max) with page_shift (32bit) and size (64bit, in pages). This should cause no behavioural change as this is changing the internal structures only - the user interface still only allows one to create a 32-bit table with 4KiB pages at this stage. Signed-off-by:
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Alexey Kardashevskiy authored
This adds a capability number for 64-bit TCE tables support. Signed-off-by:
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- 29 Feb, 2016 6 commits
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Suresh E. Warrier authored
Redirecting the wakeup of a VCPU from the H_IPI hypercall to a core running in the host is usually a good idea, most workloads seemed to benefit. However, in one heavily interrupt-driven SMT1 workload, some regression was observed. This patch adds a kvm_hv module parameter called h_ipi_redirect to control this feature. The default value for this tunable is 1 - that is enable the feature. Signed-off-by:
Suresh Warrier <warrier@linux.vnet.ibm.com> Signed-off-by:
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Suresh E. Warrier authored
This patch adds support to real-mode KVM to search for a core running in the host partition and send it an IPI message with VCPU to be woken. This avoids having to switch to the host partition to complete an H_IPI hypercall when the VCPU which is the target of the the H_IPI is not loaded (is not running in the guest). The patch also includes the support in the IPI handler running in the host to do the wakeup by calling kvmppc_xics_ipi_action for the PPC_MSG_RM_HOST_ACTION message. When a guest is being destroyed, we need to ensure that there are no pending IPIs waiting to wake up a VCPU before we free the VCPUs of the guest. This is accomplished by: - Forces a PPC_MSG_CALL_FUNCTION IPI to be completed by all CPUs before freeing any VCPUs in kvm_arch_destroy_vm(). - Any PPC_MSG_RM_HOST_ACTION messages must be executed first before any other PPC_MSG_CALL_FUNCTION messages. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
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Suresh Warrier authored
This patch adds the support for the kick VCPU operation for kvmppc_host_rm_ops. The kvmppc_xics_ipi_action() function provides the function to be invoked for a host side operation when poked by the real mode KVM. This is initiated by KVM by sending an IPI to any free host core. KVM real mode must set the rm_action to XICS_RM_KICK_VCPU and rm_data to point to the VCPU to be woken up before sending the IPI. Note that we have allocated one kvmppc_host_rm_core structure per core. The above values need to be set in the structure corresponding to the core to which the IPI will be sent. Signed-off-by:
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Suresh Warrier authored
The kvmppc_host_rm_ops structure keeps track of which cores are are in the host by maintaining a bitmask of active/runnable online CPUs that have not entered the guest. This patch adds support to manage the bitmask when a CPU is offlined or onlined in the host. Signed-off-by:
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Suresh Warrier authored
Update the core host state in kvmppc_host_rm_ops whenever the primary thread of the core enters the guest or returns back. Signed-off-by:
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Suresh Warrier authored
This patch defines the data structures to support the setting up of host side operations while running in real mode in the guest, and also the functions to allocate and free it. The operations are for now limited to virtual XICS operations. Currently, we have only defined one operation in the data structure: - Wake up a VCPU sleeping in the host when it receives a virtual interrupt The operations are assigned at the core level because PowerKVM requires that the host run in SMT off mode. For each core, we will need to manage its state atomically - where the state is defined by: 1. Is the core running in the host? 2. Is there a Real Mode (RM) operation pending on the host? Currently, core state is only managed at the whole-core level even when the system is in split-core mode. This just limits the number of free or "available" cores in the host to perform any host-side operations. The kvmppc_host_rm_core.rm_data allows any data to be passed by KVM in real mode to the host core along with the operation to be performed. The kvmppc_host_rm_ops structure is allocated the very first time a guest VM is started. Initial core state is also set - all online cores are in the host. This structure is never deleted, not even when there are no active guests. However, it needs to be freed when the module is unloaded because the kvmppc_host_rm_ops_hv can contain function pointers to kvm-hv.ko functions for the different supported host operations. Signed-off-by:
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