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* KVM: change KVM to use IOMMU APIJoerg Roedel2009-01-031-1/+1
| | | | Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
* Deassign device in kvm_free_assgined_deviceWeidong Han2009-01-031-0/+1
| | | | | | | In kvm_iommu_unmap_memslots(), assigned_dev_head is already empty. Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
* KVM: support device deassignmentWeidong Han2009-01-031-0/+42
| | | | | | | Support device deassignment, it can be used in device hotplug. Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
* KVM: use the new intel iommu APIsWeidong Han2009-01-031-1/+6
| | | | | | | | | intel iommu APIs are updated, use the new APIs. In addition, change kvm_iommu_map_guest() to just create the domain, let kvm_iommu_assign_device() assign device. Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
* KVM: fix handling of ACK from shared guest IRQMark McLoughlin2008-12-311-1/+14
| | | | | | | | | | | | | | | | | | | If an assigned device shares a guest irq with an emulated device then we currently interpret an ack generated by the emulated device as originating from the assigned device leading to e.g. "Unbalanced enable for IRQ 4347" from the enable_irq() in kvm_assigned_dev_ack_irq(). The fix is fairly simple - don't enable the physical device irq unless it was previously disabled. Of course, this can still lead to a situation where a non-assigned device ACK can cause the physical device irq to be reenabled before the device was serviced. However, being level sensitive, the interrupt will merely be regenerated. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Consolidate userspace memory capability reporting into common codeAvi Kivity2008-12-311-0/+1
| | | | Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Advertise the bug in memory region destruction as fixedAvi Kivity2008-12-311-1/+12
| | | | | | Userspace might need to act differently. Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: use cpumask_var_t for cpus_hardware_enabledRusty Russell2008-12-311-6/+14
| | | | | | | | This changes cpus_hardware_enabled from a cpumask_t to a cpumask_var_t: equivalent for CONFIG_CPUMASKS_OFFSTACK=n, otherwise dynamically allocated. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: use modern cpumask primitives, no cpumask_t on stackRusty Russell2008-12-311-9/+14
| | | | | | | | | | | | | | | | We're getting rid on on-stack cpumasks for large NR_CPUS. 1) Use cpumask_var_t/alloc_cpumask_var. 2) smp_call_function_mask -> smp_call_function_many 3) cpus_clear, cpus_empty, cpu_set -> cpumask_clear, cpumask_empty, cpumask_set_cpu. This actually generates slightly smaller code than the old one with CONFIG_CPUMASKS_OFFSTACK=n. (gcc knows that cpus cannot be NULL in that case, where cpumask_var_t is cpumask_t[1]). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Extract core of kvm_flush_remote_tlbs/kvm_reload_remote_mmusRusty Russell2008-12-311-29/+15
| | | | | | | | | | Avi said: > Wow, code duplication from Rusty. Things must be bad. Something about glass houses comes to mind. But instead, a patch. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: set owner of cpu and vm file operationsChristian Borntraeger2008-12-311-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a race between a "close of the file descriptors" and module unload in the kvm module. You can easily trigger this problem by applying this debug patch: >--- kvm.orig/virt/kvm/kvm_main.c >+++ kvm/virt/kvm/kvm_main.c >@@ -648,10 +648,14 @@ void kvm_free_physmem(struct kvm *kvm) > kvm_free_physmem_slot(&kvm->memslots[i], NULL); > } > >+#include <linux/delay.h> > static void kvm_destroy_vm(struct kvm *kvm) > { > struct mm_struct *mm = kvm->mm; > >+ printk("off1\n"); >+ msleep(5000); >+ printk("off2\n"); > spin_lock(&kvm_lock); > list_del(&kvm->vm_list); > spin_unlock(&kvm_lock); and killing the userspace, followed by an rmmod. The problem is that kvm_destroy_vm can run while the module count is 0. That means, you can remove the module while kvm_destroy_vm is running. But kvm_destroy_vm is part of the module text. This causes a kerneloops. The race exists without the msleep but is much harder to trigger. This patch requires the fix for anon_inodes (anon_inodes: use fops->owner for module refcount). With this patch, we can set the owner of all anonymous KVM inodes file operations. The VFS will then control the KVM module refcount as long as there is an open file. kvm_destroy_vm will be called by the release function of the last closed file - before the VFS drops the module refcount. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Really remove a slot when a user ask us soGlauber Costa2008-12-311-1/+4
| | | | | | | | | | | | | | | | | Right now, KVM does not remove a slot when we do a register ioctl for size 0 (would be the expected behaviour). Instead, we only mark it as empty, but keep all bitmaps and allocated data structures present. It completely nullifies our chances of reusing that same slot again for mapping a different piece of memory. In this patch, we destroy rmaps, and vfree() the pointers that used to hold the dirty bitmap, rmap and lpage_info structures. Signed-off-by: Glauber Costa <glommer@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: split out kvm_free_assigned_irq()Mark McLoughlin2008-12-311-7/+22
| | | | | | | | Split out the logic corresponding to undoing assign_irq() and clean it up a bit. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: don't free an unallocated irq source idMark McLoughlin2008-12-311-2/+5
| | | | | | | | Set assigned_dev->irq_source_id to -1 so that we can avoid freeing a source ID which we never allocated. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: fix sparse warningHannes Eder2008-12-311-1/+1
| | | | | | | | | Impact: make global function static virt/kvm/kvm_main.c:85:6: warning: symbol 'kvm_rebooting' was not declared. Should it be static? Signed-off-by: Hannes Eder <hannes@hanneseder.net> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MSI to INTx translateSheng Yang2008-12-311-16/+54
| | | | | | | | | | | | | | | | | | Now we use MSI as default one, and translate MSI to INTx when guest need INTx rather than MSI. For legacy device, we provide support for non-sharing host IRQ. Provide a parameter msi2intx for this method. The value is true by default in x86 architecture. We can't guarantee this mode can work on every device, but for most of us tested, it works. If your device encounter some trouble with this mode, you can try set msi2intx modules parameter to 0. If the device is OK with msi2intx=0, then please report it to KVM mailing list or me. We may prepare a blacklist for the device that can't work in this mode. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Enable MSI for device assignmentSheng Yang2008-12-311-6/+75
| | | | | | | | | | | | | We enable guest MSI and host MSI support in this patch. The userspace want to enable MSI should set KVM_DEV_IRQ_ASSIGN_ENABLE_MSI in the assigned_irq's flag. Function would return -ENOTTY if can't enable MSI, userspace shouldn't set MSI Enable bit when KVM_ASSIGN_IRQ return -ENOTTY with KVM_DEV_IRQ_ASSIGN_ENABLE_MSI. Userspace can tell the support of MSI device from #ifdef KVM_CAP_DEVICE_MSI. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Add assigned_device_msi_dispatch()Sheng Yang2008-12-311-0/+55
| | | | | | | | The function is used to dispatch MSI to lapic according to MSI message address and message data. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Clean up assigned_device_update_irqSheng Yang2008-12-311-6/+4
| | | | | Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Replace irq_requested with more generic irq_requested_typeSheng Yang2008-12-311-4/+5
| | | | | | | | Separate guest irq type and host irq type, for we can support guest using INTx with host using MSI (but not opposite combination). Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Separate update irq to a single functionSheng Yang2008-12-311-30/+38
| | | | | | | | Separate INTx enabling part to a independence function, so that we can add MSI enabling part easily. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Move ack notifier register and IRQ sourcd ID requestSheng Yang2008-12-311-11/+19
| | | | | | | | Distinguish common part for device assignment and INTx part, perparing for refactor later. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Fix kernel allocated memory slotSheng Yang2008-12-311-1/+1
| | | | | | | | | Commit 7fd49de9773fdcb7b75e823b21c1c5dc1e218c14 "KVM: ensure that memslot userspace addresses are page-aligned" broke kernel space allocated memory slot, for the userspace_addr is invalid. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: ensure that memslot userspace addresses are page-alignedHollis Blanchard2008-12-311-0/+2
| | | | | | | | | | Bad page translation and silent guest failure ensue if the userspace address is not page-aligned. I hit this problem using large (host) pages with qemu, because qemu currently has a hardcoded 4096-byte alignment for guest memory allocations. Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Fix aliased gfns treated as unaliasedIzik Eidus2008-12-311-4/+5
| | | | | | | | | | | Some areas of kvm x86 mmu are using gfn offset inside a slot without unaliasing the gfn first. This patch makes sure that the gfn will be unaliased and add gfn_to_memslot_unaliased() to save the calculating of the gfn unaliasing in case we have it unaliased already. Signed-off-by: Izik Eidus <ieidus@redhat.com> Acked-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Enable Function Level Reset for assigned deviceSheng Yang2008-12-311-0/+5
| | | | | | | | | | | | | | | | | | Ideally, every assigned device should in a clear condition before and after assignment, so that the former state of device won't affect later work. Some devices provide a mechanism named Function Level Reset, which is defined in PCI/PCI-e document. We should execute it before and after device assignment. (But sadly, the feature is new, and most device on the market now don't support it. We are considering using D0/D3hot transmit to emulate it later, but not that elegant and reliable as FLR itself.) [Update: Reminded by Xiantao, execute FLR after we ensure that the device can be assigned to the guest.] Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: IRQ ACK notifier should be used with in-kernel irqchipSheng Yang2008-12-311-1/+1
| | | | | | | Also remove unnecessary parameter of unregister irq ack notifier. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Fix guest shared interrupt with in-kernel irqchipSheng Yang2008-10-281-4/+8
| | | | | | | | | | | | | | | | | | | | | | Every call of kvm_set_irq() should offer an irq_source_id, which is allocated by kvm_request_irq_source_id(). Based on irq_source_id, we identify the irq source and implement logical OR for shared level interrupts. The allocated irq_source_id can be freed by kvm_free_irq_source_id(). Currently, we support at most sizeof(unsigned long) different irq sources. [Amit: - rebase to kvm.git HEAD - move definition of KVM_USERSPACE_IRQ_SOURCE_ID to common file - move kvm_request_irq_source_id to the update_irq ioctl] [Xiantao: - Add kvm/ia64 stuff and make it work for kvm/ia64 guests] Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Change is_mmio_pfn to kvm_is_mmio_pfn, and make it common for all archsXiantao Zhang2008-10-151-8/+8
| | | | | | | Add a kvm_ prefix to avoid polluting kernel's name space. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Move device assignment logic to common codeXiantao Zhang2008-10-151-2/+266
| | | | | | | | To share with other archs, this patch moves device assignment logic to common parts. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Device Assignment: Map mmio pages into VT-d page tableWeidong Han2008-10-151-1/+1
| | | | | | | | Assigned device could DMA to mmio pages, so also need to map mmio pages into VT-d page table. Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Remove useless intel-iommu.h header inclusionWeidong Han2008-10-151-1/+0
| | | | | | | | Currently "#include <linux/intel-iommu.h>" is not needed in virt/kvm/kvm_main.c. Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Don't destroy vcpu in case vcpu_setup failsGlauber Costa2008-10-151-3/+2
| | | | | | | | | | | | | One of vcpu_setup responsibilities is to do mmu initialization. However, in case we fail in kvm_arch_vcpu_reset, before we get the chance to init mmu. OTOH, vcpu_destroy will attempt to destroy mmu, triggering a bug. Keeping track of whether or not mmu is initialized would unnecessarily complicate things. Rather, we just make return, making sure any needed uninitialization is done before we return, in case we fail. Signed-off-by: Glauber Costa <glommer@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: switch to get_user_pages_fastMarcelo Tosatti2008-10-151-5/+5
| | | | | | | | | Convert gfn_to_pfn to use get_user_pages_fast, which can do lockless pagetable lookups on x86. Kernel compilation on 4-way guest is 3.7% faster on VMX. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: opencode gfn_to_page in kvm_vm_faultMarcelo Tosatti2008-10-151-7/+12
| | | | | | | | | kvm_vm_fault is invoked with mmap_sem held in read mode. Since gfn_to_page will be converted to get_user_pages_fast, which requires this lock NOT to be held, switch to opencoded get_user_pages. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Device Assignment with VT-dBen-Ami Yassour2008-10-151-1/+8
| | | | | | | | | | | | | | | | | | | Based on a patch by: Kay, Allen M <allen.m.kay@intel.com> This patch enables PCI device assignment based on VT-d support. When a device is assigned to the guest, the guest memory is pinned and the mapping is updated in the VT-d IOMMU. [Amit: Expose KVM_CAP_IOMMU so we can check if an IOMMU is present and also control enable/disable from userspace] Signed-off-by: Kay, Allen M <allen.m.kay@intel.com> Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Amit Shah <amit.shah@qumranet.com> Acked-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: x86: do not execute halted vcpusMarcelo Tosatti2008-10-151-5/+5
| | | | | | | | | | | | | | Offline or uninitialized vcpu's can be executed if requested to perform userspace work. Follow Avi's suggestion to handle halted vcpu's in the main loop, simplifying kvm_emulate_halt(). Introduce a new vcpu->requests bit to indicate events that promote state from halted to running. Also standardize vcpu wake sites. Signed-off-by: Marcelo Tosatti <mtosatti <at> redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Don't call get_user_pages(.force = 1)Avi Kivity2008-10-151-1/+1
| | | | | | | | This is esoteric and only needed to break COW on MAP_SHARED mappings. Since KVM no longer does these sorts of mappings, breaking COW on them is no longer necessary. Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Reduce stack usage in kvm_vcpu_ioctl()Dave Hansen2008-10-151-18/+28
| | | | | Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: direct mmio pfn checkBen-Ami Yassour2008-10-151-7/+15
| | | | | | | | | | Userspace may specify memory slots that are backed by mmio pages rather than normal RAM. In some cases it is not enough to identify these mmio pages by pfn_valid(). This patch adds checking the PageReserved as well. Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Synchronize guest physical memory map to host virtual memory mapAndrea Arcangeli2008-07-291-0/+135
| | | | | | | | | | Synchronize changes to host virtual addresses which are part of a KVM memory slot to the KVM shadow mmu. This allows pte operations like swapping, page migration, and madvise() to transparently work with KVM. Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Allow browsing memslots with mmu_lockAndrea Arcangeli2008-07-291-4/+16
| | | | | | | | This allows reading memslots with only the mmu_lock hold for mmu notifiers that runs in atomic context and with mmu_lock held. Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* flag parameters: anon_inode_getfd extensionUlrich Drepper2008-07-241-2/+2
| | | | | | | | | | | | | | | This patch just extends the anon_inode_getfd interface to take an additional parameter with a flag value. The flag value is passed on to get_unused_fd_flags in anticipation for a use with the O_CLOEXEC flag. No actual semantic changes here, the changed callers all pass 0 for now. [akpm@linux-foundation.org: KVM fix] Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* KVM: Adjust smp_call_function_mask() callers to new requirementsAvi Kivity2008-07-201-6/+12
| | | | | | | smp_call_function_mask() now complains when called in a preemptible context; adjust its callers accordingly. Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: MMU: nuke shadowed pgtable pages and ptes on memslot destructionMarcelo Tosatti2008-07-201-0/+3
| | | | | | | Flush the shadow mmu before removing regions to avoid stale entries. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: s390: dont allocate dirty bitmapCarsten Otte2008-07-201-0/+2
| | | | | | | | | | | This patch #ifdefs the bitmap array for dirty tracking. We don't have dirty tracking on s390 today, and we'd love to use our storage keys to store the dirty information for migration. Therefore, we won't need this array at all, and due to our limited amount of vmalloc space this limits the amount of guests we can run. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Add coalesced MMIO support (common part)Laurent Vivier2008-07-201-0/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds all needed structures to coalesce MMIOs. Until an architecture uses it, it is not compiled. Coalesced MMIO introduces two ioctl() to define where are the MMIO zones that can be coalesced: - KVM_REGISTER_COALESCED_MMIO registers a coalesced MMIO zone. It requests one parameter (struct kvm_coalesced_mmio_zone) which defines a memory area where MMIOs can be coalesced until the next switch to user space. The maximum number of MMIO zones is KVM_COALESCED_MMIO_ZONE_MAX. - KVM_UNREGISTER_COALESCED_MMIO cancels all registered zones inside the given bounds (bounds are also given by struct kvm_coalesced_mmio_zone). The userspace client can check kernel coalesced MMIO availability by asking ioctl(KVM_CHECK_EXTENSION) for the KVM_CAP_COALESCED_MMIO capability. The ioctl() call to KVM_CAP_COALESCED_MMIO will return 0 if not supported, or the page offset where will be stored the ring buffer. The page offset depends on the architecture. After an ioctl(KVM_RUN), the first page of the KVM memory mapped points to a kvm_run structure. The offset given by KVM_CAP_COALESCED_MMIO is an offset to the coalesced MMIO ring expressed in PAGE_SIZE relatively to the address of the start of th kvm_run structure. The MMIO ring buffer is defined by the structure kvm_coalesced_mmio_ring. [akio: fix oops during guest shutdown] Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: kvm_io_device: extend in_range() to manage len and write attributeLaurent Vivier2008-07-201-2/+3
| | | | | | | | | | Modify member in_range() of structure kvm_io_device to pass length and the type of the I/O (write or read). This modification allows to use kvm_io_device with coalesced MMIO. Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Remove decache_vcpus_on_cpu() and related callbacksAvi Kivity2008-07-201-1/+0
| | | | | | Obsoleted by the vmx-specific per-cpu list. Signed-off-by: Avi Kivity <avi@qumranet.com>
* KVM: Handle virtualization instruction #UD faults during rebootAvi Kivity2008-07-201-0/+15
| | | | | | | | | | | | | | | KVM turns off hardware virtualization extensions during reboot, in order to disassociate the memory used by the virtualization extensions from the processor, and in order to have the system in a consistent state. Unfortunately virtual machines may still be running while this goes on, and once virtualization extensions are turned off, any virtulization instruction will #UD on execution. Fix by adding an exception handler to virtualization instructions; if we get an exception during reboot, we simply spin waiting for the reset to complete. If it's a true exception, BUG() so we can have our stack trace. Signed-off-by: Avi Kivity <avi@qumranet.com>