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2020-10-23kvm: x86/mmu: NX largepage recovery for TDP MMUBen Gardon
When KVM maps a largepage backed region at a lower level in order to make it executable (i.e. NX large page shattering), it reduces the TLB performance of that region. In order to avoid making this degradation permanent, KVM must periodically reclaim shattered NX largepages by zapping them and allowing them to be rebuilt in the page fault handler. With this patch, the TDP MMU does not respect KVM's rate limiting on reclaim. It traverses the entire TDP structure every time. This will be addressed in a future patch. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-21-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Don't clear write flooding count for direct rootsBen Gardon
Direct roots don't have a write flooding count because the guest can't affect that paging structure. Thus there's no need to clear the write flooding count on a fast CR3 switch for direct roots. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-20-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Support MMIO in the TDP MMUBen Gardon
In order to support MMIO, KVM must be able to walk the TDP paging structures to find mappings for a given GFN. Support this walk for the TDP MMU. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 v2: Thanks to Dan Carpenter and kernel test robot for finding that root was used uninitialized in get_mmio_spte. Signed-off-by: Ben Gardon <bgardon@google.com> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Message-Id: <20201014182700.2888246-19-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Support write protection for nesting in tdp MMUBen Gardon
To support nested virtualization, KVM will sometimes need to write protect pages which are part of a shadowed paging structure or are not writable in the shadowed paging structure. Add a function to write protect GFN mappings for this purpose. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-18-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Support disabling dirty logging for the tdp MMUBen Gardon
Dirty logging ultimately breaks down MMU mappings to 4k granularity. When dirty logging is no longer needed, these granaular mappings represent a useless performance penalty. When dirty logging is disabled, search the paging structure for mappings that could be re-constituted into a large page mapping. Zap those mappings so that they can be faulted in again at a higher mapping level. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-17-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Support dirty logging for the TDP MMUBen Gardon
Dirty logging is a key feature of the KVM MMU and must be supported by the TDP MMU. Add support for both the write protection and PML dirty logging modes. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-16-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Support changed pte notifier in tdp MMUBen Gardon
In order to interoperate correctly with the rest of KVM and other Linux subsystems, the TDP MMU must correctly handle various MMU notifiers. Add a hook and handle the change_pte MMU notifier. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-15-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Add access tracking for tdp_mmuBen Gardon
In order to interoperate correctly with the rest of KVM and other Linux subsystems, the TDP MMU must correctly handle various MMU notifiers. The main Linux MM uses the access tracking MMU notifiers for swap and other features. Add hooks to handle the test/flush HVA (range) family of MMU notifiers. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-14-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMUBen Gardon
In order to interoperate correctly with the rest of KVM and other Linux subsystems, the TDP MMU must correctly handle various MMU notifiers. Add hooks to handle the invalidate range family of MMU notifiers. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-13-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMUBen Gardon
Attach struct kvm_mmu_pages to every page in the TDP MMU to track metadata, facilitate NX reclaim, and enable inproved parallelism of MMU operations in future patches. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-12-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23kvm: x86/mmu: Add TDP MMU PF handlerBen Gardon
Add functions to handle page faults in the TDP MMU. These page faults are currently handled in much the same way as the x86 shadow paging based MMU, however the ordering of some operations is slightly different. Future patches will add eager NX splitting, a fast page fault handler, and parallel page faults. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-11-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator argBen Gardon
In order to avoid creating executable hugepages in the TDP MMU PF handler, remove the dependency between disallowed_hugepage_adjust and the shadow_walk_iterator. This will open the function up to being used by the TDP MMU PF handler in a future patch. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-10-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Support zapping SPTEs in the TDP MMUBen Gardon
Add functions to zap SPTEs to the TDP MMU. These are needed to tear down TDP MMU roots properly and implement other MMU functions which require tearing down mappings. Future patches will add functions to populate the page tables, but as for this patch there will not be any work for these functions to do. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-8-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Add functions to handle changed TDP SPTEsBen Gardon
The existing bookkeeping done by KVM when a PTE is changed is spread around several functions. This makes it difficult to remember all the stats, bitmaps, and other subsystems that need to be updated whenever a PTE is modified. When a non-leaf PTE is marked non-present or becomes a leaf PTE, page table memory must also be freed. To simplify the MMU and facilitate the use of atomic operations on SPTEs in future patches, create functions to handle some of the bookkeeping required as a result of a change. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Allocate and free TDP MMU rootsBen Gardon
The TDP MMU must be able to allocate paging structure root pages and track the usage of those pages. Implement a similar, but separate system for root page allocation to that of the x86 shadow paging implementation. When future patches add synchronization model changes to allow for parallel page faults, these pages will need to be handled differently from the x86 shadow paging based MMU's root pages. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Init / Uninit the TDP MMUBen Gardon
The TDP MMU offers an alternative mode of operation to the x86 shadow paging based MMU, optimized for running an L1 guest with TDP. The TDP MMU will require new fields that need to be initialized and torn down. Add hooks into the existing KVM MMU initialization process to do that initialization / cleanup. Currently the initialization and cleanup fucntions do not do very much, however more operations will be added in future patches. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20201014182700.2888246-4-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Introduce tdp_iterBen Gardon
The TDP iterator implements a pre-order traversal of a TDP paging structure. This iterator will be used in future patches to create an efficient implementation of the KVM MMU for the TDP case. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: mmu: extract spte.h and spte.cPaolo Bonzini
The SPTE format will be common to both the shadow and the TDP MMU. Extract code that implements the format to a separate module, as a first step towards adding the TDP MMU and putting mmu.c on a diet. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: mmu: Separate updating a PTE from kvm_set_pte_rmappPaolo Bonzini
The TDP MMU's own function for the changed-PTE notifier will need to be update a PTE in the exact same way as the shadow MMU. Rather than re-implementing this logic, factor the SPTE creation out of kvm_set_pte_rmapp. Extracted out of a patch by Ben Gardon. <bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86/mmu: Separate making SPTEs from set_spteBen Gardon
Separate the functions for generating leaf page table entries from the function that inserts them into the paging structure. This refactoring will facilitate changes to the MMU sychronization model to use atomic compare / exchanges (which are not guaranteed to succeed) instead of a monolithic MMU lock. No functional change expected. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This commit introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Shier <pshier@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: mmu: Separate making non-leaf sptes from link_shadow_pageBen Gardon
The TDP MMU page fault handler will need to be able to create non-leaf SPTEs to build up the paging structures. Rather than re-implementing the function, factor the SPTE creation out of link_shadow_page. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20200925212302.3979661-9-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21Merge branch 'kvm-fixes' into 'next'Paolo Bonzini
Pick up bugfixes from 5.9, otherwise various tests fail.
2020-10-21KVM: PPC: Book3S HV: Make struct kernel_param_ops definition constJoe Perches
This should be const, so make it so. Signed-off-by: Joe Perches <joe@perches.com> Message-Id: <d130e88dd4c82a12d979da747cc0365c72c3ba15.1601770305.git.joe@perches.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: Let the guest own CR4.FSGSBASELai Jiangshan
Add FSGSBASE to the set of possible guest-owned CR4 bits, i.e. let the guest own it on VMX. KVM never queries the guest's CR4.FSGSBASE value, thus there is no reason to force VM-Exit on FSGSBASE being toggled. Note, because FSGSBASE is conditionally available, this is dependent on recent changes to intercept reserved CR4 bits and to update the CR4 guest/host mask in response to guest CPUID changes. Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> [sean: added justification in changelog] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200930041659.28181-6-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: VMX: Intercept guest reserved CR4 bits to inject #GP faultSean Christopherson
Intercept CR4 bits that are guest reserved so that KVM correctly injects a #GP fault if the guest attempts to set a reserved bit. If a feature is supported by the CPU but is not exposed to the guest, and its associated CR4 bit is not intercepted by KVM by default, then KVM will fail to inject a #GP if the guest sets the CR4 bit without triggering an exit, e.g. by toggling only the bit in question. Note, KVM doesn't give the guest direct access to any CR4 bits that are also dependent on guest CPUID. Yet. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200930041659.28181-5-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: Move call to update_exception_bitmap() into VMX codeSean Christopherson
Now that vcpu_after_set_cpuid() and update_exception_bitmap() are called back-to-back, subsume the exception bitmap update into the common CPUID update. Drop the SVM invocation entirely as SVM's exception bitmap doesn't vary with respect to guest CPUID. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200930041659.28181-4-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: Invoke vendor's vcpu_after_set_cpuid() after all common updatesSean Christopherson
Move the call to kvm_x86_ops.vcpu_after_set_cpuid() to the very end of kvm_vcpu_after_set_cpuid() to allow the vendor implementation to react to changes made by the common code. In the near future, this will be used by VMX to update its CR4 guest/host masks to account for reserved bits. In the long term, SGX support will update the allowed XCR0 mask for enclaves based on the vCPU's allowed XCR0. vcpu_after_set_cpuid() (nee kvm_update_cpuid()) was originally added by commit 2acf923e38fb ("KVM: VMX: Enable XSAVE/XRSTOR for guest"), and was called separately after kvm_x86_ops.vcpu_after_set_cpuid() (nee kvm_x86_ops->cpuid_update()). There is no indication that the placement of the common code updates after the vendor updates was anything more than a "new function at the end" decision. Inspection of the current code reveals no dependency on kvm_x86_ops' vcpu_after_set_cpuid() in kvm_vcpu_after_set_cpuid() or any of its helpers. The bulk of the common code depends only on the guest's CPUID configuration, kvm_mmu_reset_context() does not consume dynamic vendor state, and there are no collisions between kvm_pmu_refresh() and VMX's update of PT state. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200930041659.28181-3-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: Intercept LA57 to inject #GP fault when it's reservedLai Jiangshan
Unconditionally intercept changes to CR4.LA57 so that KVM correctly injects a #GP fault if the guest attempts to set CR4.LA57 when it's supported in hardware but not exposed to the guest. Long term, KVM needs to properly handle CR4 bits that can be under guest control but also may be reserved from the guest's perspective. But, KVM currently sets the CR4 guest/host mask only during vCPU creation, and reworking flows to change that will take a bit of elbow grease. Even if/when generic support for intercepting reserved bits exists, it's probably not worth letting the guest set CR4.LA57 directly. LA57 can't be toggled while long mode is enabled, thus it's all but guaranteed to be set once (maybe twice, e.g. by BIOS and kernel) during boot and never touched again. On the flip side, letting the guest own CR4.LA57 may incur extra VMREADs. In other words, this temporary "hack" is probably also the right long term fix. Fixes: fd8cb433734e ("KVM: MMU: Expose the LA57 feature to VM.") Cc: stable@vger.kernel.org Cc: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> [sean: rewrote changelog] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200930041659.28181-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: SVM: Initialize prev_ga_tag before useSuravee Suthikulpanit
The function amd_ir_set_vcpu_affinity makes use of the parameter struct amd_iommu_pi_data.prev_ga_tag to determine if it should delete struct amd_iommu_pi_data from a list when not running in AVIC mode. However, prev_ga_tag is initialized only when AVIC is enabled. The non-zero uninitialized value can cause unintended code path, which ends up making use of the struct vcpu_svm.ir_list and ir_list_lock without being initialized (since they are intended only for the AVIC case). This triggers NULL pointer dereference bug in the function vm_ir_list_del with the following call trace: svm_update_pi_irte+0x3c2/0x550 [kvm_amd] ? proc_create_single_data+0x41/0x50 kvm_arch_irq_bypass_add_producer+0x40/0x60 [kvm] __connect+0x5f/0xb0 [irqbypass] irq_bypass_register_producer+0xf8/0x120 [irqbypass] vfio_msi_set_vector_signal+0x1de/0x2d0 [vfio_pci] vfio_msi_set_block+0x77/0xe0 [vfio_pci] vfio_pci_set_msi_trigger+0x25c/0x2f0 [vfio_pci] vfio_pci_set_irqs_ioctl+0x88/0xb0 [vfio_pci] vfio_pci_ioctl+0x2ea/0xed0 [vfio_pci] ? alloc_file_pseudo+0xa5/0x100 vfio_device_fops_unl_ioctl+0x26/0x30 [vfio] ? vfio_device_fops_unl_ioctl+0x26/0x30 [vfio] __x64_sys_ioctl+0x96/0xd0 do_syscall_64+0x37/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Therefore, initialize prev_ga_tag to zero before use. This should be safe because ga_tag value 0 is invalid (see function avic_vm_init). Fixes: dfa20099e26e ("KVM: SVM: Refactor AVIC vcpu initialization into avic_init_vcpu()") Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20201003232707.4662-1-suravee.suthikulpanit@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: nSVM: implement on demand allocation of the nested stateMaxim Levitsky
This way we don't waste memory on VMs which don't use nesting virtualization even when the host enabled it for them. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201001112954.6258-5-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: allow kvm_x86_ops.set_efer to return an error valueMaxim Levitsky
This will be used to signal an error to the userspace, in case the vendor code failed during handling of this msr. (e.g -ENOMEM) Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201001112954.6258-4-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: report negative values from wrmsr emulation to userspaceMaxim Levitsky
This will allow the KVM to report such errors (e.g -ENOMEM) to the userspace. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201001112954.6258-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: xen_hvm_config: cleanup return valuesMaxim Levitsky
Return 1 on errors that are caused by wrong guest behavior (which will inject #GP to the guest) And return a negative error value on issues that are the kernel's fault (e.g -ENOMEM) Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201001112954.6258-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm x86/mmu: Make struct kernel_param_ops definitions constJoe Perches
These should be const, so make it so. Signed-off-by: Joe Perches <joe@perches.com> Message-Id: <ed95eef4f10fc1317b66936c05bc7dd8f943a6d5.1601770305.git.joe@perches.com> Reviewed-by: Ben Gardon <bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: bump KVM_MAX_CPUID_ENTRIESVitaly Kuznetsov
As vcpu->arch.cpuid_entries is now allocated dynamically, the only remaining use for KVM_MAX_CPUID_ENTRIES is to check KVM_SET_CPUID/ KVM_SET_CPUID2 input for sanity. Since it was reported that the current limit (80) is insufficient for some CPUs, bump KVM_MAX_CPUID_ENTRIES and use an arbitrary value '256' as the new limit. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20201001130541.1398392-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: x86: allocate vcpu->arch.cpuid_entries dynamicallyVitaly Kuznetsov
The current limit for guest CPUID leaves (KVM_MAX_CPUID_ENTRIES, 80) is reported to be insufficient but before we bump it let's switch to allocating vcpu->arch.cpuid_entries[] array dynamically. Currently, 'struct kvm_cpuid_entry2' is 40 bytes so vcpu->arch.cpuid_entries is 3200 bytes which accounts for 1/4 of the whole 'struct kvm_vcpu_arch' but having it pre-allocated (for all vCPUs which we also pre-allocate) gives us no real benefits. Another plus of the dynamic allocation is that we now do kvm_check_cpuid() check before we assign anything to vcpu->arch.cpuid_nent/cpuid_entries so no changes are made in case the check fails. Opportunistically remove unneeded 'out' labels from kvm_vcpu_ioctl_set_cpuid()/kvm_vcpu_ioctl_set_cpuid2() and return directly whenever possible. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20201001130541.1398392-3-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
2020-10-21KVM: x86: disconnect kvm_check_cpuid() from vcpu->arch.cpuid_entriesVitaly Kuznetsov
As a preparatory step to allocating vcpu->arch.cpuid_entries dynamically make kvm_check_cpuid() check work with an arbitrary 'struct kvm_cpuid_entry2' array. Currently, when kvm_check_cpuid() fails we reset vcpu->arch.cpuid_nent to 0 and this is kind of weird, i.e. one would expect CPUIDs to remain unchanged when KVM_SET_CPUID[2] call fails. No functional change intended. It would've been possible to move the updated kvm_check_cpuid() in kvm_vcpu_ioctl_set_cpuid2() and check the supplied input before we start updating vcpu->arch.cpuid_entries/nent but we can't do the same in kvm_vcpu_ioctl_set_cpuid() as we'll have to copy 'struct kvm_cpuid_entry' entries first. The change will be made when vcpu->arch.cpuid_entries[] array becomes allocated dynamically. Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20201001130541.1398392-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86: only provide PV features if enabled in guest's CPUIDOliver Upton
KVM unconditionally provides PV features to the guest, regardless of the configured CPUID. An unwitting guest that doesn't check KVM_CPUID_FEATURES before use could access paravirt features that userspace did not intend to provide. Fix this by checking the guest's CPUID before performing any paravirtual operations. Introduce a capability, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, to gate the aforementioned enforcement. Migrating a VM from a host w/o this patch to a host with this patch could silently change the ABI exposed to the guest, warranting that we default to the old behavior and opt-in for the new one. Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Change-Id: I202a0926f65035b872bfe8ad15307c026de59a98 Message-Id: <20200818152429.1923996-4-oupton@google.com> Reviewed-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86: set wall_clock in kvm_write_wall_clock()Oliver Upton
Small change to avoid meaningless duplication in the subsequent patch. No functional change intended. Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Change-Id: I77ab9cdad239790766b7a49d5cbae5e57a3005ea Message-Id: <20200818152429.1923996-3-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21kvm: x86: encapsulate wrmsr(MSR_KVM_SYSTEM_TIME) emulation in helper fnOliver Upton
No functional change intended. Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Reviewed-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Oliver Upton <oupton@google.com> Change-Id: I7cbe71069db98d1ded612fd2ef088b70e7618426 Message-Id: <20200818152429.1923996-2-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21x86/kvm: Update the comment about asynchronous page fault in exc_page_fault()Vitaly Kuznetsov
KVM was switched to interrupt-based mechanism for 'page ready' event delivery in Linux-5.8 (see commit 2635b5c4a0e4 ("KVM: x86: interrupt based APF 'page ready' event delivery")) and #PF (ab)use for 'page ready' event delivery was removed. Linux guest switched to this new mechanism exclusively in 5.9 (see commit b1d405751cd5 ("KVM: x86: Switch KVM guest to using interrupts for page ready APF delivery")) so it is not possible to get #PF for a 'page ready' event even when the guest is running on top of an older KVM (APF mechanism won't be enabled). Update the comment in exc_page_fault() to reflect the new reality. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20201002154313.1505327-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21x86/kvm: hide KVM options from menuconfig when KVM is not compiledMatteo Croce
Let KVM_WERROR depend on KVM, so it doesn't show in menuconfig alone. Signed-off-by: Matteo Croce <mcroce@microsoft.com> Message-Id: <20201001112014.9561-1-mcroce@linux.microsoft.com> Fixes: 4f337faf1c55e ("KVM: allow disabling -Werror") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: VMX: Forbid userspace MSR filters for x2APICPaolo Bonzini
Allowing userspace to intercept reads to x2APIC MSRs when APICV is fully enabled for the guest simply can't work. But more in general, the LAPIC could be set to in-kernel after the MSR filter is setup and allowing accesses by userspace would be very confusing. We could in principle allow userspace to intercept reads and writes to TPR, and writes to EOI and SELF_IPI, but while that could be made it work, it would still be silly. Cc: Alexander Graf <graf@amazon.com> Cc: Aaron Lewis <aaronlewis@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: VMX: Ignore userspace MSR filters for x2APICSean Christopherson
Rework the resetting of the MSR bitmap for x2APIC MSRs to ignore userspace filtering. Allowing userspace to intercept reads to x2APIC MSRs when APICV is fully enabled for the guest simply can't work; the LAPIC and thus virtual APIC is in-kernel and cannot be directly accessed by userspace. To keep things simple we will in fact forbid intercepting x2APIC MSRs altogether, independent of the default_allow setting. Cc: Alexander Graf <graf@amazon.com> Cc: Aaron Lewis <aaronlewis@google.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20201005195532.8674-3-sean.j.christopherson@intel.com> [Modified to operate even if APICv is disabled, adjust documentation. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-20Merge tag 'kvmarm-5.10' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for Linux 5.10 - New page table code for both hypervisor and guest stage-2 - Introduction of a new EL2-private host context - Allow EL2 to have its own private per-CPU variables - Support of PMU event filtering - Complete rework of the Spectre mitigation
2020-10-19KVM: VMX: Fix x2APIC MSR intercept handling on !APICV platformsPeter Xu
Fix an inverted flag for intercepting x2APIC MSRs and intercept writes by default, even when APICV is enabled. Fixes: 3eb900173c71 ("KVM: x86: VMX: Prevent MSR passthrough when MSR access is denied") Co-developed-by: Peter Xu <peterx@redhat.com> [sean: added changelog] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20201005195532.8674-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-03Merge tag 'kvmarm-fixes-5.9-3' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master KVM/arm64 fixes for 5.9, take #3 - Fix synchronization of VTTBR update on TLB invalidation for nVHE systems
2020-10-03KVM: VMX: update PFEC_MASK/PFEC_MATCH together with PF interceptPaolo Bonzini
The PFEC_MASK and PFEC_MATCH fields in the VMCS reverse the meaning of the #PF intercept bit in the exception bitmap when they do not match. This means that, if PFEC_MASK and/or PFEC_MATCH are set, the hypervisor can get a vmexit for #PF exceptions even when the corresponding bit is clear in the exception bitmap. This is unexpected and is promptly detected by a WARN_ON_ONCE. To fix it, reset PFEC_MASK and PFEC_MATCH when the #PF intercept is disabled (as is common with enable_ept && !allow_smaller_maxphyaddr). Reported-by: Qian Cai <cai@redhat.com>> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-02Merge branches 'kvm-arm64/pt-new' and 'kvm-arm64/pmu-5.9' into ↵Marc Zyngier
kvmarm-master/next Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-10-02KVM: arm64: Ensure user_mem_abort() return value is initialisedWill Deacon
If a change in the MMU notifier sequence number forces user_mem_abort() to return early when attempting to handle a stage-2 fault, we return uninitialised stack to kvm_handle_guest_abort(), which could potentially result in the injection of an external abort into the guest or a spurious return to userspace. Neither or these are what we want to do. Initialise 'ret' to 0 in user_mem_abort() so that bailing due to a change in the MMU notrifier sequence number is treated as though the fault was handled. Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20200930102442.16142-1-will@kernel.org
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