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2022-09-01KVM: x86: check validity of argument to KVM_SET_MP_STATEPaolo Bonzini
An invalid argument to KVM_SET_MP_STATE has no effect other than making the vCPU fail to run at the next KVM_RUN. Since it is extremely unlikely that any userspace is relying on it, fail with -EINVAL just like for other architectures. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-01KVM: x86: fix memoryleak in kvm_arch_vcpu_create()Miaohe Lin
When allocating memory for mci_ctl2_banks fails, KVM doesn't release mce_banks leading to memoryleak. Fix this issue by calling kfree() for it when kcalloc() fails. Fixes: 281b52780b57 ("KVM: x86: Add emulation for MSR_IA32_MCx_CTL2 MSRs.") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Message-Id: <20220901122300.22298-1-linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-01KVM: x86: Mask off unsupported and unknown bits of IA32_ARCH_CAPABILITIESJim Mattson
KVM should not claim to virtualize unknown IA32_ARCH_CAPABILITIES bits. When kvm_get_arch_capabilities() was originally written, there were only a few bits defined in this MSR, and KVM could virtualize all of them. However, over the years, several bits have been defined that KVM cannot just blindly pass through to the guest without additional work (such as virtualizing an MSR promised by the IA32_ARCH_CAPABILITES feature bit). Define a mask of supported IA32_ARCH_CAPABILITIES bits, and mask off any other bits that are set in the hardware MSR. Cc: Paolo Bonzini <pbonzini@redhat.com> Fixes: 5b76a3cff011 ("KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Message-Id: <20220830174947.2182144-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19kvm: x86: mmu: Always flush TLBs when enabling dirty loggingJunaid Shahid
When A/D bits are not available, KVM uses a software access tracking mechanism, which involves making the SPTEs inaccessible. However, the clear_young() MMU notifier does not flush TLBs. So it is possible that there may still be stale, potentially writable, TLB entries. This is usually fine, but can be problematic when enabling dirty logging, because it currently only does a TLB flush if any SPTEs were modified. But if all SPTEs are in access-tracked state, then there won't be a TLB flush, which means that the guest could still possibly write to memory and not have it reflected in the dirty bitmap. So just unconditionally flush the TLBs when enabling dirty logging. As an alternative, KVM could explicitly check the MMU-Writable bit when write-protecting SPTEs to decide if a flush is needed (instead of checking the Writable bit), but given that a flush almost always happens anyway, so just making it unconditional seems simpler. Signed-off-by: Junaid Shahid <junaids@google.com> Message-Id: <20220810224939.2611160-1-junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-11Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull more kvm updates from Paolo Bonzini: - Xen timer fixes - Documentation formatting fixes - Make rseq selftest compatible with glibc-2.35 - Fix handling of illegal LEA reg, reg - Cleanup creation of debugfs entries - Fix steal time cache handling bug - Fixes for MMIO caching - Optimize computation of number of LBRs - Fix uninitialized field in guest_maxphyaddr < host_maxphyaddr path * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (26 commits) KVM: x86/MMU: properly format KVM_CAP_VM_DISABLE_NX_HUGE_PAGES capability table Documentation: KVM: extend KVM_CAP_VM_DISABLE_NX_HUGE_PAGES heading underline KVM: VMX: Adjust number of LBR records for PERF_CAPABILITIES at refresh KVM: VMX: Use proper type-safe functions for vCPU => LBRs helpers KVM: x86: Refresh PMU after writes to MSR_IA32_PERF_CAPABILITIES KVM: selftests: Test all possible "invalid" PERF_CAPABILITIES.LBR_FMT vals KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test KVM: selftests: Make rseq compatible with glibc-2.35 KVM: Actually create debugfs in kvm_create_vm() KVM: Pass the name of the VM fd to kvm_create_vm_debugfs() KVM: Get an fd before creating the VM KVM: Shove vcpu stats_id init into kvm_vcpu_init() KVM: Shove vm stats_id init into kvm_create_vm() KVM: x86/mmu: Add sanity check that MMIO SPTE mask doesn't overlap gen KVM: x86/mmu: rename trace function name for asynchronous page fault KVM: x86/xen: Stop Xen timer before changing IRQ KVM: x86/xen: Initialize Xen timer only once KVM: SVM: Disable SEV-ES support if MMIO caching is disable KVM: x86/mmu: Fully re-evaluate MMIO caching when SPTE masks change KVM: x86: Tag kvm_mmu_x86_module_init() with __init ...
2022-08-10KVM: x86: Refresh PMU after writes to MSR_IA32_PERF_CAPABILITIESSean Christopherson
Refresh the PMU if userspace modifies MSR_IA32_PERF_CAPABILITIES. KVM consumes the vCPU's PERF_CAPABILITIES when enumerating PEBS support, but relies on CPUID updates to refresh the PMU. I.e. KVM will do the wrong thing if userspace stuffs PERF_CAPABILITIES _after_ setting guest CPUID. Opportunistically fix a curly-brace indentation. Fixes: c59a1f106f5c ("KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS") Cc: Like Xu <like.xu.linux@gmail.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220727233424.2968356-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: X86: avoid uninitialized 'fault.async_page_fault' from fixed-up #PFYu Zhang
kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( e.g., to add RSVD flag) and inject the #PF to the guest, when guest MAXPHYADDR is smaller than the host one. When it comes to nested, L0 is expected to intercept and fix up the #PF and then inject to L2 directly if - L2.MAXPHYADDR < L0.MAXPHYADDR and - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the same MAXPHYADDR value && L1 is using EPT for L2), instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK and PFEC_MATCH both set to 0 in vmcs02, the interception and injection may happen on all L2 #PFs. However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() may cause the fault.async_page_fault being NOT zeroed, and later the #PF being treated as a nested async page fault, and then being injected to L1. Instead of zeroing 'fault' at the beginning of this function, we mannually set the value of 'fault.async_page_fault', because false is the value we really expect. Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 Reported-by: Yang Lixiao <lixiao.yang@intel.com> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220718074756.53788-1-yu.c.zhang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: do not report preemption if the steal time cache is stalePaolo Bonzini
Commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status", 2021-11-11) open coded the previous call to kvm_map_gfn, but in doing so it dropped the comparison between the cached guest physical address and the one in the MSR. This cause an incorrect cache hit if the guest modifies the steal time address while the memslots remain the same. This can happen with kexec, in which case the preempted bit is written at the address used by the old kernel instead of the old one. Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: stable@vger.kernel.org Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: revalidate steal time cache if MSR value changesPaolo Bonzini
Commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status", 2021-11-11) open coded the previous call to kvm_map_gfn, but in doing so it dropped the comparison between the cached guest physical address and the one in the MSR. This cause an incorrect cache hit if the guest modifies the steal time address while the memslots remain the same. This can happen with kexec, in which case the steal time data is written at the address used by the old kernel instead of the old one. While at it, rename the variable from gfn to gpa since it is a plain physical address and not a right-shifted one. Reported-by: Dave Young <ruyang@redhat.com> Reported-by: Xiaoying Yan <yiyan@redhat.com> Analyzed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: stable@vger.kernel.org Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-06Merge tag 'iommu-updates-v5.20-or-v6.0' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu Pull iommu updates from Joerg Roedel: - The most intrusive patch is small and changes the default allocation policy for DMA addresses. Before the change the allocator tried its best to find an address in the first 4GB. But that lead to performance problems when that space gets exhaused, and since most devices are capable of 64-bit DMA these days, we changed it to search in the full DMA-mask range from the beginning. This change has the potential to uncover bugs elsewhere, in the kernel or the hardware. There is a Kconfig option and a command line option to restore the old behavior, but none of them is enabled by default. - Add Robin Murphy as reviewer of IOMMU code and maintainer for the dma-iommu and iova code - Chaning IOVA magazine size from 1032 to 1024 bytes to save memory - Some core code cleanups and dead-code removal - Support for ACPI IORT RMR node - Support for multiple PCI domains in the AMD-Vi driver - ARM SMMU changes from Will Deacon: - Add even more Qualcomm device-tree compatible strings - Support dumping of IMP DEF Qualcomm registers on TLB sync timeout - Fix reference count leak on device tree node in Qualcomm driver - Intel VT-d driver updates from Lu Baolu: - Make intel-iommu.h private - Optimize the use of two locks - Extend the driver to support large-scale platforms - Cleanup some dead code - MediaTek IOMMU refactoring and support for TTBR up to 35bit - Basic support for Exynos SysMMU v7 - VirtIO IOMMU driver gets a map/unmap_pages() implementation - Other smaller cleanups and fixes * tag 'iommu-updates-v5.20-or-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (116 commits) iommu/amd: Fix compile warning in init code iommu/amd: Add support for AVIC when SNP is enabled iommu/amd: Simplify and Consolidate Virtual APIC (AVIC) Enablement ACPI/IORT: Fix build error implicit-function-declaration drivers: iommu: fix clang -wformat warning iommu/arm-smmu: qcom_iommu: Add of_node_put() when breaking out of loop iommu/arm-smmu-qcom: Add SM6375 SMMU compatible dt-bindings: arm-smmu: Add compatible for Qualcomm SM6375 MAINTAINERS: Add Robin Murphy as IOMMU SUBSYTEM reviewer iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled iommu/amd: Do not support IOMMU_DOMAIN_IDENTITY after SNP is enabled iommu/amd: Set translation valid bit only when IO page tables are in use iommu/amd: Introduce function to check and enable SNP iommu/amd: Globally detect SNP support iommu/amd: Process all IVHDs before enabling IOMMU features iommu/amd: Introduce global variable for storing common EFR and EFR2 iommu/amd: Introduce Support for Extended Feature 2 Register iommu/amd: Change macro for IOMMU control register bit shift to decimal value iommu/exynos: Enable default VM instance on SysMMU v7 iommu/exynos: Add SysMMU v7 register set ...
2022-08-01Merge remote-tracking branch 'kvm/next' into kvm-next-5.20Paolo Bonzini
KVM/s390, KVM/x86 and common infrastructure changes for 5.20 x86: * Permit guests to ignore single-bit ECC errors * Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache * Intel IPI virtualization * Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS * PEBS virtualization * Simplify PMU emulation by just using PERF_TYPE_RAW events * More accurate event reinjection on SVM (avoid retrying instructions) * Allow getting/setting the state of the speaker port data bit * Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent * "Notify" VM exit (detect microarchitectural hangs) for Intel * Cleanups for MCE MSR emulation s390: * add an interface to provide a hypervisor dump for secure guests * improve selftests to use TAP interface * enable interpretive execution of zPCI instructions (for PCI passthrough) * First part of deferred teardown * CPU Topology * PV attestation * Minor fixes Generic: * new selftests API using struct kvm_vcpu instead of a (vm, id) tuple x86: * Use try_cmpxchg64 instead of cmpxchg64 * Bugfixes * Ignore benign host accesses to PMU MSRs when PMU is disabled * Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior * x86/MMU: Allow NX huge pages to be disabled on a per-vm basis * Port eager page splitting to shadow MMU as well * Enable CMCI capability by default and handle injected UCNA errors * Expose pid of vcpu threads in debugfs * x2AVIC support for AMD * cleanup PIO emulation * Fixes for LLDT/LTR emulation * Don't require refcounted "struct page" to create huge SPTEs x86 cleanups: * Use separate namespaces for guest PTEs and shadow PTEs bitmasks * PIO emulation * Reorganize rmap API, mostly around rmap destruction * Do not workaround very old KVM bugs for L0 that runs with nesting enabled * new selftests API for CPUID
2022-07-29Merge branches 'arm/exynos', 'arm/mediatek', 'arm/msm', 'arm/smmu', ↵Joerg Roedel
'virtio', 'x86/vt-d', 'x86/amd' and 'core' into next
2022-07-28KVM: x86: Split kvm_is_valid_cr4() and export only the non-vendor bitsSean Christopherson
Split the common x86 parts of kvm_is_valid_cr4(), i.e. the reserved bits checks, into a separate helper, __kvm_is_valid_cr4(), and export only the inner helper to vendor code in order to prevent nested VMX from calling back into vmx_is_valid_cr4() via kvm_is_valid_cr4(). On SVM, this is a nop as SVM doesn't place any additional restrictions on CR4. On VMX, this is also currently a nop, but only because nested VMX is missing checks on reserved CR4 bits for nested VM-Enter. That bug will be fixed in a future patch, and could simply use kvm_is_valid_cr4() as-is, but nVMX has _another_ bug where VMXON emulation doesn't enforce VMX's restrictions on CR0/CR4. The cleanest and most intuitive way to fix the VMXON bug is to use nested_host_cr{0,4}_valid(). If the CR4 variant routes through kvm_is_valid_cr4(), using nested_host_cr4_valid() won't do the right thing for the VMXON case as vmx_is_valid_cr4() enforces VMX's restrictions if and only if the vCPU is post-VMXON. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220607213604.3346000-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-28KVM: x86: Drop unnecessary goto+label in kvm_arch_init()Sean Christopherson
Return directly if kvm_arch_init() detects an error before doing any real work, jumping through a label obfuscates what's happening and carries the unnecessary risk of leaving 'r' uninitialized. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220715230016.3762909-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-28KVM: x86: Reject loading KVM if host.PAT[0] != WBSean Christopherson
Reject KVM if entry '0' in the host's IA32_PAT MSR is not programmed to writeback (WB) memtype. KVM subtly relies on IA32_PAT entry '0' to be programmed to WB by leaving the PAT bits in shadow paging and NPT SPTEs as '0'. If something other than WB is in PAT[0], at _best_ guests will suffer very poor performance, and at worst KVM will crash the system by breaking cache-coherency expecations (e.g. using WC for guest memory). Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220715230016.3762909-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-19KVM: x86: Protect the unused bits in MSR exiting flagsAaron Lewis
The flags for KVM_CAP_X86_USER_SPACE_MSR and KVM_X86_SET_MSR_FILTER have no protection for their unused bits. Without protection, future development for these features will be difficult. Add the protection needed to make it possible to extend these features in the future. Signed-off-by: Aaron Lewis <aaronlewis@google.com> Message-Id: <20220714161314.1715227-1-aaronlewis@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-15KVM: x86: Remove unnecessary includeLu Baolu
intel-iommu.h is not needed in kvm/x86 anymore. Remove its include. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Steve Wahl <steve.wahl@hpe.com> Link: https://lore.kernel.org/r/20220514014322.2927339-6-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2022-07-14KVM: x86: Fully initialize 'struct kvm_lapic_irq' in kvm_pv_kick_cpu_op()Vitaly Kuznetsov
'vector' and 'trig_mode' fields of 'struct kvm_lapic_irq' are left uninitialized in kvm_pv_kick_cpu_op(). While these fields are normally not needed for APIC_DM_REMRD, they're still referenced by __apic_accept_irq() for trace_kvm_apic_accept_irq(). Fully initialize the structure to avoid consuming random stack memory. Fixes: a183b638b61c ("KVM: x86: make apic_accept_irq tracepoint more generic") Reported-by: syzbot+d6caa905917d353f0d07@syzkaller.appspotmail.com Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220708125147.593975-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-14KVM: x86: Add dedicated helper to get CPUID entry with significant indexSean Christopherson
Add a second CPUID helper, kvm_find_cpuid_entry_index(), to handle KVM queries for CPUID leaves whose index _may_ be significant, and drop the index param from the existing kvm_find_cpuid_entry(). Add a WARN in the inner helper, cpuid_entry2_find(), to detect attempts to retrieve a CPUID entry whose index is significant without explicitly providing an index. Using an explicit magic number and letting callers omit the index avoids confusion by eliminating the myriad cases where KVM specifies '0' as a dummy value. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-14kvm: stats: tell userspace which values are booleanPaolo Bonzini
Some of the statistics values exported by KVM are always only 0 or 1. It can be useful to export this fact to userspace so that it can track them specially (for example by polling the value every now and then to compute a % of time spent in a specific state). Therefore, add "boolean value" as a new "unit". While it is not exactly a unit, it walks and quacks like one. In particular, using the type would be wrong because boolean values could be instantaneous or peak values (e.g. "is the rmap allocated?") or even two-bucket histograms (e.g. "number of posted vs. non-posted interrupt injections"). Suggested-by: Amneesh Singh <natto@weirdnatto.in> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-13KVM: x86: WARN only once if KVM leaves a dangling userspace I/O requestSean Christopherson
Change a WARN_ON() to separate WARN_ON_ONCE() if KVM has an outstanding PIO or MMIO request without an associated callback, i.e. if KVM queued a userspace I/O exit but didn't actually exit to userspace before moving on to something else. Warning on every KVM_RUN risks spamming the kernel if KVM gets into a bad state. Opportunistically split the WARNs so that it's easier to triage failures when a WARN fires. Deliberately do not use KVM_BUG_ON(), i.e. don't kill the VM. While the WARN is all but guaranteed to fire if and only if there's a KVM bug, a dangling I/O request does not present a danger to KVM (that flag is truly truly consumed only in a single emulator path), and any such bug is unlikely to be fatal to the VM (KVM essentially failed to do something it shouldn't have tried to do in the first place). In other words, note the bug, but let the VM keep running. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20220711232750.1092012-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-07-13KVM: x86: Tweak name of MONITOR/MWAIT #UD quirk to make it #UD specificSean Christopherson
Add a "UD" clause to KVM_X86_QUIRK_MWAIT_NEVER_FAULTS to make it clear that the quirk only controls the #UD behavior of MONITOR/MWAIT. KVM doesn't currently enforce fault checks when MONITOR/MWAIT are supported, but that could change in the future. SVM also has a virtualization hole in that it checks all faults before intercepts, and so "never faults" is already a lie when running on SVM. Fixes: bfbcc81bb82c ("KVM: x86: Add a quirk for KVM's "MONITOR/MWAIT are NOPs!" behavior") Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220711225753.1073989-4-seanjc@google.com
2022-07-12KVM: x86/mmu: Replace UNMAPPED_GVA with INVALID_GPA for gva_to_gpa()Hou Wenlong
The result of gva_to_gpa() is physical address not virtual address, it is odd that UNMAPPED_GVA macro is used as the result for physical address. Replace UNMAPPED_GVA with INVALID_GPA and drop UNMAPPED_GVA macro. No functional change intended. Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/6104978956449467d3c68f1ad7f2c2f6d771d0ee.1656667239.git.houwenlong.hwl@antgroup.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-07-08KVM: x86: Fully initialize 'struct kvm_lapic_irq' in kvm_pv_kick_cpu_op()Vitaly Kuznetsov
'vector' and 'trig_mode' fields of 'struct kvm_lapic_irq' are left uninitialized in kvm_pv_kick_cpu_op(). While these fields are normally not needed for APIC_DM_REMRD, they're still referenced by __apic_accept_irq() for trace_kvm_apic_accept_irq(). Fully initialize the structure to avoid consuming random stack memory. Fixes: a183b638b61c ("KVM: x86: make apic_accept_irq tracepoint more generic") Reported-by: syzbot+d6caa905917d353f0d07@syzkaller.appspotmail.com Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220708125147.593975-1-vkuznets@redhat.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-07-08KVM: x86: Fix handling of APIC LVT updates when userspace changes MCG_CAPSean Christopherson
Add a helper to update KVM's in-kernel local APIC in response to MCG_CAP being changed by userspace to fix multiple bugs. First and foremost, KVM needs to check that there's an in-kernel APIC prior to dereferencing vcpu->arch.apic. Beyond that, any "new" LVT entries need to be masked, and the APIC version register needs to be updated as it reports out the number of LVT entries. Fixes: 4b903561ec49 ("KVM: x86: Add Corrected Machine Check Interrupt (CMCI) emulation to lapic.") Reported-by: syzbot+8cdad6430c24f396f158@syzkaller.appspotmail.com Cc: Siddh Raman Pant <code@siddh.me> Cc: Jue Wang <juew@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-07-08Merge branch 'kvm-5.20-msr-eperm'Sean Christopherson
Merge a bug fix and cleanups for {g,s}et_msr_mce() using a base that predates commit 281b52780b57 ("KVM: x86: Add emulation for MSR_IA32_MCx_CTL2 MSRs."), which was written with the intention that it be applied _after_ the bug fix and cleanups. The bug fix in particular needs to be sent to stable trees; give them a stable hash to use.
2022-07-08KVM: x86: Add helpers to identify CTL and STATUS MCi MSRsSean Christopherson
Add helpers to identify CTL (control) and STATUS MCi MSR types instead of open coding the checks using the offset. Using the offset is perfectly safe, but unintuitive, as understanding what the code does requires knowing that the offset calcuation will not affect the lower three bits. Opportunistically comment the STATUS logic to save readers a trip to Intel's SDM or AMD's APM to understand the "data != 0" check. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Link: https://lore.kernel.org/r/20220512222716.4112548-4-seanjc@google.com
2022-07-08KVM: x86: Use explicit case-statements for MCx banks in {g,s}et_msr_mce()Sean Christopherson
Use an explicit case statement to grab the full range of MCx bank MSRs in {g,s}et_msr_mce(), and manually check only the "end" (the number of banks configured by userspace may be less than the max). The "default" trick works, but is a bit odd now, and will be quite odd if/when support for accessing MCx_CTL2 MSRs is added, which has near identical logic. Hoist "offset" to function scope so as to avoid curly braces for the case statement, and because MCx_CTL2 support will need the same variables. Opportunstically clean up the comment about allowing bit 10 to be cleared from bank 4. No functional change intended. Cc: Jue Wang <juew@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Link: https://lore.kernel.org/r/20220512222716.4112548-3-seanjc@google.com
2022-07-08KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS)Sean Christopherson
Return '1', not '-1', when handling an illegal WRMSR to a MCi_CTL or MCi_STATUS MSR. The behavior of "all zeros' or "all ones" for CTL MSRs is architectural, as is the "only zeros" behavior for STATUS MSRs. I.e. the intent is to inject a #GP, not exit to userspace due to an unhandled emulation case. Returning '-1' gets interpreted as -EPERM up the stack and effecitvely kills the guest. Fixes: 890ca9aefa78 ("KVM: Add MCE support") Fixes: 9ffd986c6e4e ("KVM: X86: #GP when guest attempts to write MCi_STATUS register w/o 0") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Link: https://lore.kernel.org/r/20220512222716.4112548-2-seanjc@google.com
2022-06-27x86/kvm/vmx: Make noinstr cleanPeter Zijlstra
The recent mmio_stale_data fixes broke the noinstr constraints: vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0x15b: call to wrmsrl.constprop.0() leaves .noinstr.text section vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0x1bf: call to kvm_arch_has_assigned_device() leaves .noinstr.text section make it all happy again. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-24KVM: SEV-ES: reuse advance_sev_es_emulated_ins for OUT tooPaolo Bonzini
complete_emulator_pio_in() only has to be called by complete_sev_es_emulated_ins() now; therefore, all that the function does now is adjust sev_pio_count and sev_pio_data. Which is the same for both IN and OUT. No functional change intended. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: de-underscorify __emulator_pio_inPaolo Bonzini
Now all callers except emulator_pio_in_emulated are using __emulator_pio_in/complete_emulator_pio_in explicitly. Move the "either copy the result or attempt PIO" logic in emulator_pio_in_emulated, and rename __emulator_pio_in to just emulator_pio_in. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: wean fast IN from emulator_pio_inPaolo Bonzini
Use __emulator_pio_in() directly for fast PIO instead of bouncing through emulator_pio_in() now that __emulator_pio_in() fills "val" when handling in-kernel PIO. vcpu->arch.pio.count is guaranteed to be '0', so this a pure nop. emulator_pio_in_emulated is now the last caller of emulator_pio_in. No functional change intended. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: wean in-kernel PIO from vcpu->arch.pio*Paolo Bonzini
Make emulator_pio_in_out operate directly on the provided buffer as long as PIO is handled inside KVM. For input operations, this means that, in the case of in-kernel PIO, __emulator_pio_in() does not have to be always followed by complete_emulator_pio_in(). This affects emulator_pio_in() and kvm_sev_es_ins(); for the latter, that is why the call moves from advance_sev_es_emulated_ins() to complete_sev_es_emulated_ins(). For output, it means that vcpu->pio.count is never set unnecessarily and there is no need to clear it; but also vcpu->pio.size must not be used in kvm_sev_es_outs(), because it will not be updated for in-kernel OUT. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out()Paolo Bonzini
For now, this is basically an excuse to add back the void* argument to the function, while removing some knowledge of vcpu->arch.pio* from its callers. The WARN that vcpu->arch.pio.count is zero is also extended to OUT operations. The vcpu->arch.pio* fields still need to be filled even when the PIO is handled in-kernel as __emulator_pio_in() is always followed by complete_emulator_pio_in(). But after fixing that, it will be possible to to only populate the vcpu->arch.pio* fields on userspace exits. No functional change intended. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: drop PIO from unregistered devicesPaolo Bonzini
KVM protects the device list with SRCU, and therefore different calls to kvm_io_bus_read()/kvm_io_bus_write() can very well see different incarnations of kvm->buses. If userspace unregisters a device while vCPUs are running there is no well-defined result. This patch applies a safe fallback by returning early from emulator_pio_in_out(). This corresponds to returning zeroes from IN, and dropping the writes on the floor for OUT. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: inline kernel_pio into its sole callerPaolo Bonzini
The caller of kernel_pio already has arguments for most of what kernel_pio fishes out of vcpu->arch.pio. This is the first step towards ensuring that vcpu->arch.pio.* is only used when exiting to userspace. No functional change intended. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: complete fast IN directly with complete_emulator_pio_in()Paolo Bonzini
Use complete_emulator_pio_in() directly when completing fast PIO, there's no need to bounce through emulator_pio_in(): the comment about ECX changing doesn't apply to fast PIO, which isn't used for string I/O. No functional change intended. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SVM: Add AVIC doorbell tracepointSuravee Suthikulpanit
Add a tracepoint to track number of doorbells being sent to signal a running vCPU to process IRQ after being injected. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-17-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Warning APICv inconsistency only when vcpu APIC mode is validSuravee Suthikulpanit
When launching a VM with x2APIC and specify more than 255 vCPUs, the guest kernel can disable x2APIC (e.g. specify nox2apic kernel option). The VM fallbacks to xAPIC mode, and disable the vCPU ID 255 and greater. In this case, APICV is deactivated for the disabled vCPUs. However, the current APICv consistency warning does not account for this case, which results in a warning. Therefore, modify warning logic to report only when vCPU APIC mode is valid. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-15-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Deactivate APICv on vCPU with APIC disabledSuravee Suthikulpanit
APICv should be deactivated on vCPU that has APIC disabled. Therefore, call kvm_vcpu_update_apicv() when changing APIC mode, and add additional check for APIC disable mode when determine APICV activation, Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-9-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Enable CMCI capability by default and handle injected UCNA errorsJue Wang
This patch enables MCG_CMCI_P by default in kvm_mce_cap_supported. It reuses ioctl KVM_X86_SET_MCE to implement injection of UnCorrectable No Action required (UCNA) errors, signaled via Corrected Machine Check Interrupt (CMCI). Neither of the CMCI and UCNA emulations depends on hardware. Signed-off-by: Jue Wang <juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220610171134.772566-8-juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Add emulation for MSR_IA32_MCx_CTL2 MSRs.Jue Wang
This patch adds the emulation of IA32_MCi_CTL2 registers to KVM. A separate mci_ctl2_banks array is used to keep the existing mce_banks register layout intact. In Machine Check Architecture, in addition to MCG_CMCI_P, bit 30 of the per-bank register IA32_MCi_CTL2 controls whether Corrected Machine Check error reporting is enabled. Signed-off-by: Jue Wang <juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220610171134.772566-7-juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Use kcalloc to allocate the mce_banks array.Jue Wang
This patch updates the allocation of mce_banks with the array allocation API (kcalloc) as a precedent for the later mci_ctl2_banks to implement per-bank control of Corrected Machine Check Interrupt (CMCI). Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Jue Wang <juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220610171134.772566-6-juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Add Corrected Machine Check Interrupt (CMCI) emulation to lapic.Jue Wang
This patch calculates the number of lvt entries as part of KVM_X86_MCE_SETUP conditioned on the presence of MCG_CMCI_P bit in MCG_CAP and stores result in kvm_lapic. It translats from APIC_LVTx register to index in lapic_lvt_entry enum. It extends the APIC_LVTx macro as well as other lapic write/reset handling etc to support Corrected Machine Check Interrupt. Signed-off-by: Jue Wang <juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220610171134.772566-5-juew@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86/MMU: Allow NX huge pages to be disabled on a per-vm basisBen Gardon
In some cases, the NX hugepage mitigation for iTLB multihit is not needed for all guests on a host. Allow disabling the mitigation on a per-VM basis to avoid the performance hit of NX hugepages on trusted workloads. In order to disable NX hugepages on a VM, ensure that the userspace actor has permission to reboot the system. Since disabling NX hugepages would allow a guest to crash the system, it is similar to reboot permissions. Ideally, KVM would require userspace to prove it has access to KVM's nx_huge_pages module param, e.g. so that userspace can opt out without needing full reboot permissions. But getting access to the module param file info is difficult because it is buried in layers of sysfs and module glue. Requiring CAP_SYS_BOOT is sufficient for all known use cases. Suggested-by: Jim Mattson <jmattson@google.com> Reviewed-by: David Matlack <dmatlack@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20220613212523.3436117-9-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: Fix errant brace in KVM capability handlingBen Gardon
The braces around the KVM_CAP_XSAVE2 block also surround the KVM_CAP_PMU_CAPABILITY block, likely the result of a merge issue. Simply move the curly brace back to where it belongs. Fixes: ba7bb663f5547 ("KVM: x86: Provide per VM capability for disabling PMU virtualization") Reviewed-by: David Matlack <dmatlack@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20220613212523.3436117-8-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20KVM: x86: Add a quirk for KVM's "MONITOR/MWAIT are NOPs!" behaviorSean Christopherson
Add a quirk for KVM's behavior of emulating intercepted MONITOR/MWAIT instructions a NOPs regardless of whether or not they are supported in guest CPUID. KVM's current behavior was likely motiviated by a certain fruity operating system that expects MONITOR/MWAIT to be supported unconditionally and blindly executes MONITOR/MWAIT without first checking CPUID. And because KVM does NOT advertise MONITOR/MWAIT to userspace, that's effectively the default setup for any VMM that regurgitates KVM_GET_SUPPORTED_CPUID to KVM_SET_CPUID2. Note, this quirk interacts with KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT. The behavior is actually desirable, as userspace VMMs that want to unconditionally hide MONITOR/MWAIT from the guest can leave the MISC_ENABLE quirk enabled. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220608224516.3788274-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20KVM: x86: Ignore benign host writes to "unsupported" F15H_PERF_CTL MSRsSean Christopherson
Ignore host userspace writes of '0' to F15H_PERF_CTL MSRs KVM reports in the MSR-to-save list, but the MSRs are ultimately unsupported. All MSRs in said list must be writable by userspace, e.g. if userspace sends the list back at KVM without filtering out the MSRs it doesn't need. Note, reads of said MSRs already have the desired behavior. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220611005755.753273-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20KVM: x86: Ignore benign host accesses to "unsupported" PEBS and BTS MSRsSean Christopherson
Ignore host userspace reads and writes of '0' to PEBS and BTS MSRs that KVM reports in the MSR-to-save list, but the MSRs are ultimately unsupported. All MSRs in said list must be writable by userspace, e.g. if userspace sends the list back at KVM without filtering out the MSRs it doesn't need. Fixes: 8183a538cd95 ("KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to support guest DS") Fixes: 902caeb6841a ("KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS") Fixes: c59a1f106f5c ("KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220611005755.753273-7-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>