- 25 Oct, 2021 3 commits
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David Edmondson authored
Should instruction emulation fail, include the VM exit reason, etc. in the emulation_failure data passed to userspace, in order that the VMM can report it as a debugging aid when describing the failure. Suggested-by:
Joao Martins <joao.m.martins@oracle.com> Signed-off-by:
David Edmondson <david.edmondson@oracle.com> Reviewed-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210920103737.2696756-4-david.edmondson@oracle.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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David Edmondson authored
Extend the get_exit_info static call to provide the reason for the VM exit. Modify relevant trace points to use this rather than extracting the reason in the caller. Signed-off-by:
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David Edmondson authored
Until more flags for kvm_run.emulation_failure flags are defined, it is undetermined whether new payload elements corresponding to those flags will be additive or alternative. As a hint to userspace that an alternative is possible, wrap the current payload elements in a union. Suggested-by:
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- 22 Oct, 2021 28 commits
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Jim Mattson authored
Though gcc conveniently compiles a simple memset to "rep stos," clang prefers to call the libc version of memset. If a test is dynamically linked, the libc memset isn't available in L1 (nor is the PLT or the GOT, for that matter). Even if the test is statically linked, the libc memset may choose to use some CPU features, like AVX, which may not be enabled in L1. Note that __builtin_memset doesn't solve the problem, because (a) the compiler is free to call memset anyway, and (b) __builtin_memset may also choose to use features like AVX, which may not be available in L1. To avoid a myriad of problems, use an explicit "rep stos" to clear the VMCB in generic_svm_setup(), which is called both from L0 and L1. Reported-by:
Ricardo Koller <ricarkol@google.com> Signed-off-by:
Jim Mattson <jmattson@google.com> Fixes: 20ba262f ("selftests: KVM: AMD Nested test infrastructure") Message-Id: <20210930003649.4026553-1-jmattson@google.com> Signed-off-by:
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Jim Mattson authored
This variable was renamed to kvm_has_noapic_vcpu in commit 6e4e3b4d ("KVM: Stop using deprecated jump label APIs"). Signed-off-by:
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Sean Christopherson authored
Unregister KVM's posted interrupt wakeup handler during unsetup so that a spurious interrupt that arrives after kvm_intel.ko is unloaded doesn't call into freed memory. Fixes: bf9f6ac8 ("KVM: Update Posted-Interrupts Descriptor when vCPU is blocked") Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Add a synchronize_rcu() after clearing the posted interrupt wakeup handler to ensure all readers, i.e. in-flight IRQ handlers, see the new handler before returning to the caller. If the caller is an exiting module and is unregistering its handler, failure to wait could result in the IRQ handler jumping into an unloaded module. The registration path doesn't require synchronization, as it's the caller's responsibility to not generate interrupts it cares about until after its handler is registered. Fixes: f6b3c72c ("x86/irq: Define a global vector for VT-d Posted-Interrupts") Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Use a rw_semaphore instead of a mutex to coordinate APICv updates so that vCPUs responding to requests can take the lock for read and run in parallel. Using a mutex forces serialization of vCPUs even though kvm_vcpu_update_apicv() only touches data local to that vCPU or is protected by a different lock, e.g. SVM's ir_list_lock. Signed-off-by:
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Sean Christopherson authored
Move SVM's assertion that vCPU's APICv state is consistent with its VM's state out of svm_vcpu_run() and into x86's common inner run loop. The assertion and underlying logic is not unique to SVM, it's just that SVM has more inhibiting conditions and thus is more likely to run headfirst into any KVM bugs. Add relevant comments to document exactly why the update path has unusual ordering between the update the kick, why said ordering is safe, and also the basic rules behind the assertion in the run loop. Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
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Lukas Bulwahn authored
Commit 99cdc6c1 ("RISC-V: Add initial skeletal KVM support") selects the config ANON_INODES in config KVM, but the config ANON_INODES is removed since commit 5dd50aae ("Make anon_inodes unconditional") in 2018. Hence, ./scripts/checkkconfigsymbols.py warns on non-existing symbols: ANON_INODES Referencing files: arch/riscv/kvm/Kconfig Remove selecting the non-existing config ANON_INODES. Signed-off-by:
Lukas Bulwahn <lukas.bulwahn@gmail.com> Message-Id: <20211022061514.25946-1-lukas.bulwahn@gmail.com> Signed-off-by:
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Sean Christopherson authored
Extract the zapping of rmaps, a.k.a. legacy MMU, for a gfn range to a separate helper to clean up the unholy mess that kvm_zap_gfn_range() has become. In addition to deep nesting, the rmaps zapping spreads out the declaration of several variables and is generally a mess. Clean up the mess now so that future work to improve the memslots implementation doesn't need to deal with it. Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by:
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Sean Christopherson authored
Remove an unnecessary remote TLB flush in kvm_zap_gfn_range() now that said function holds mmu_lock for write for its entire duration. The flush was added by the now-reverted commit to allow TDP MMU to flush while holding mmu_lock for read, as the transition from write=>read required dropping the lock and thus a pending flush needed to be serviced. Fixes: 5a324c24 ("Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock"") Cc: Maxim Levitsky <mlevitsk@redhat.com> Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Cc: Ben Gardon <bgardon@google.com> Signed-off-by:
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Sean Christopherson authored
A recent commit to fix the calls to kvm_flush_remote_tlbs_with_address() in kvm_zap_gfn_range() inadvertantly added yet another flush instead of fixing the existing flush. Drop the redundant flush, and fix the params for the existing flush. Cc: stable@vger.kernel.org Fixes: 2822da44 ("KVM: x86/mmu: fix parameters to kvm_flush_remote_tlbs_with_address") Cc: Maxim Levitsky <mlevitsk@redhat.com> Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by:
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Lai Jiangshan authored
kvm_mmu_unload() destroys all the PGD caches. Use the lighter kvm_mmu_sync_roots() and kvm_mmu_sync_prev_roots() instead. Signed-off-by:
Lai Jiangshan <laijs@linux.alibaba.com> Message-Id: <20211019110154.4091-5-jiangshanlai@gmail.com> Signed-off-by:
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Lai Jiangshan authored
The commit 578e1c4d ("kvm: x86: Avoid taking MMU lock in kvm_mmu_sync_roots if no sync is needed") added smp_wmb() in mmu_try_to_unsync_pages(), but the corresponding smp_load_acquire() isn't used on the load of SPTE.W. smp_load_acquire() orders _subsequent_ loads after sp->is_unsync; it does not order _earlier_ loads before the load of sp->is_unsync. This has no functional change; smp_rmb() is a NOP on x86, and no compiler barrier is required because there is a VMEXIT between the load of SPTE.W and kvm_mmu_snc_roots. Cc: Junaid Shahid <junaids@google.com> Signed-off-by:
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Lai Jiangshan authored
The commit 21823fbd ("KVM: x86: Invalidate all PGDs for the current PCID on MOV CR3 w/ flush") invalidates all PGDs for the specific PCID and in the case of PCID is disabled, it includes all PGDs in the prev_roots and the commit made prev_roots totally unused in this case. Not using prev_roots fixes a problem when CR4.PCIDE is changed 0 -> 1 before the said commit: (CR4.PCIDE=0, CR4.PGE=1; CR3=cr3_a; the page for the guest RIP is global; cr3_b is cached in prev_roots) modify page tables under cr3_b the shadow root of cr3_b is unsync in kvm INVPCID single context the guest expects the TLB is clean for PCID=0 change CR4.PCIDE 0 -> 1 switch to cr3_b with PCID=0,NOFLUSH=1 No sync in kvm, cr3_b is still unsync in kvm jump to the page that was modified in step 1 shadow page tables point to the wrong page It is a very unlikely case, but it shows that stale prev_roots can be a problem after CR4.PCIDE changes from 0 to 1. However, to fix this case, the commit disabled caching CR3 in prev_roots altogether when PCID is disabled. Not all CPUs have PCID; especially the PCID support for AMD CPUs is kind of recent. To restore the prev_roots optimization for CR4.PCIDE=0, flush the whole MMU (including all prev_roots) when CR4.PCIDE changes. Signed-off-by:
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Lai Jiangshan authored
The KVM doesn't know whether any TLB for a specific pcid is cached in the CPU when tdp is enabled. So it is better to flush all the guest TLB when invalidating any single PCID context. The case is very rare or even impossible since KVM generally doesn't intercept CR3 write or INVPCID instructions when tdp is enabled, so the fix is mostly for the sake of overall robustness. Signed-off-by:
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Lai Jiangshan authored
X86_CR4_PGE doesn't participate in kvm_mmu_role, so the mmu context doesn't need to be reset. It is only required to flush all the guest tlb. It is also inconsistent that X86_CR4_PGE is in KVM_MMU_CR4_ROLE_BITS while kvm_mmu_role doesn't use X86_CR4_PGE. So X86_CR4_PGE is also removed from KVM_MMU_CR4_ROLE_BITS. Signed-off-by:
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Lai Jiangshan authored
X86_CR4_PCIDE doesn't participate in kvm_mmu_role, so the mmu context doesn't need to be reset. It is only required to flush all the guest tlb. Signed-off-by:
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Michael Roth authored
Recent kernels have checks to ensure the GPA values in special-purpose registers like CR3 are within the maximum physical address range and don't overlap with anything in the upper/reserved range. In the case of SEV kselftest guests booting directly into 64-bit mode, CR3 needs to be initialized to the GPA of the page table root, with the encryption bit set. The kernel accounts for this encryption bit by removing it from reserved bit range when the guest advertises the bit position via KVM_SET_CPUID*, but kselftests currently call KVM_SET_SREGS as part of vm_vcpu_add_default(), before KVM_SET_CPUID*. As a result, KVM_SET_SREGS will return an error in these cases. Address this by moving vcpu_set_cpuid() (which calls KVM_SET_CPUID*) ahead of vcpu_setup() (which calls KVM_SET_SREGS). While there, address a typo in the assertion that triggers when KVM_SET_SREGS fails. Suggested-by:
Michael Roth <michael.roth@amd.com> Message-Id: <20211006203617.13045-1-michael.roth@amd.com> Signed-off-by:
Nathan Tempelman <natet@google.com>
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Wanpeng Li authored
SDM mentioned that, RDPMC: IF (((CR4.PCE = 1) or (CPL = 0) or (CR0.PE = 0)) and (ECX indicates a supported counter)) THEN EAX := counter[31:0]; EDX := ZeroExtend(counter[MSCB:32]); ELSE (* ECX is not valid or CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1 *) #GP(0); FI; Let's add a comment why CR0.PE isn't tested since it's impossible for CPL to be >0 if CR0.PE=0. Signed-off-by:Wanpeng Li <wanpengli@tencent.com> Message-Id: <1634724836-73721-1-git-send-email-wanpengli@tencent.com> Signed-off-by:
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Sean Christopherson authored
Paul pointed out the error messages when KVM fails to load are unhelpful in understanding exactly what went wrong if userspace probes the "wrong" module. Add a mandatory kvm_x86_ops field to track vendor module names, kvm_intel and kvm_amd, and use the name for relevant error message when KVM fails to load so that the user knows which module failed to load. Opportunistically tweak the "disabled by bios" error message to clarify that _support_ was disabled, not that the module itself was magically disabled by BIOS. Suggested-by:
Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by:
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Junaid Shahid authored
Currently, the NX huge page recovery thread wakes up every minute and zaps 1/nx_huge_pages_recovery_ratio of the total number of split NX huge pages at a time. This is intended to ensure that only a relatively small number of pages get zapped at a time. But for very large VMs (or more specifically, VMs with a large number of executable pages), a period of 1 minute could still result in this number being too high (unless the ratio is changed significantly, but that can result in split pages lingering on for too long). This change makes the period configurable instead of fixing it at 1 minute. Users of large VMs can then adjust the period and/or the ratio to reduce the number of pages zapped at one time while still maintaining the same overall duration for cycling through the entire list. By default, KVM derives a period from the ratio such that a page will remain on the list for 1 hour on average. Signed-off-by:
Junaid Shahid <junaids@google.com> Message-Id: <20211020010627.305925-1-junaids@google.com> Signed-off-by:
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Wanpeng Li authored
SDM section 18.2.3 mentioned that: "IA32_PERF_GLOBAL_OVF_CTL MSR allows software to clear overflow indicator(s) of any general-purpose or fixed-function counters via a single WRMSR." It is R/W mentioned by SDM, we read this msr on bare-metal during perf testing, the value is always 0 for ICX/SKX boxes on hands. Let's fill get_msr MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0 as hardware behavior and drop global_ovf_ctrl variable. Tested-by:
Like Xu <likexu@tencent.com> Signed-off-by:
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David Matlack authored
slot_handle_leaf is a misnomer because it only operates on 4K SPTEs whereas "leaf" is used to describe any valid terminal SPTE (4K or large page). Rename slot_handle_leaf to slot_handle_level_4k to avoid confusion. Making this change makes it more obvious there is a benign discrepency between the legacy MMU and the TDP MMU when it comes to dirty logging. The legacy MMU only iterates through 4K SPTEs when zapping for collapsing and when clearing D-bits. The TDP MMU, on the other hand, iterates through SPTEs on all levels. The TDP MMU behavior of zapping SPTEs at all levels is technically overkill for its current dirty logging implementation, which always demotes to 4k SPTES, but both the TDP MMU and legacy MMU zap if and only if the SPTE can be replaced by a larger page, i.e. will not spuriously zap 2m (or larger) SPTEs. Opportunistically add comments to explain this discrepency in the code. Signed-off-by:
David Matlack <dmatlack@google.com> Message-Id: <20211019162223.3935109-1-dmatlack@google.com> Signed-off-by:
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Xiaoyao Li authored
Per Intel SDM, RTIT_CTL_BRANCH_EN bit has no dependency on any CPUID leaf 0x14. Signed-off-by:
Xiaoyao Li <xiaoyao.li@intel.com> Message-Id: <20210827070249.924633-5-xiaoyao.li@intel.com> Signed-off-by:
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Xiaoyao Li authored
To better self explain the meaning of this field and match the PT_CAP_num_address_ranges constatn. Suggested-by:
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Xiaoyao Li authored
The number of valid PT ADDR MSRs for the guest is precomputed in vmx->pt_desc.addr_range. Use it instead of calculating again. Signed-off-by:
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Xiaoyao Li authored
A minor optimization to WRMSR MSR_IA32_RTIT_CTL when necessary. Opportunistically refine the comment to call out that KVM requires VM_EXIT_CLEAR_IA32_RTIT_CTL to expose PT to the guest. Reviewed-by:
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Paolo Bonzini authored
"prefetch", "prefault" and "speculative" are used throughout KVM to mean the same thing. Use a single name, standardizing on "prefetch" which is already used by various functions such as direct_pte_prefetch, FNAME(prefetch_gpte), FNAME(pte_prefetch), etc. Suggested-by:
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David Stevens authored
Unify the flags for rmaps and page tracking data, using a single flag in struct kvm_arch and a single loop to go over all the address spaces and memslots. This avoids code duplication between alloc_all_memslots_rmaps and kvm_page_track_enable_mmu_write_tracking. Signed-off-by:
David Stevens <stevensd@chromium.org> [This patch is the delta between David's v2 and v3, with conflicts fixed and my own commit message. - Paolo] Co-developed-by:
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- 18 Oct, 2021 9 commits
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Oliver Upton authored
Introduce a KVM selftest to verify that userspace manipulation of the TSC (via the new vCPU attribute) results in the correct behavior within the guest. Reviewed-by:
Andrew Jones <drjones@redhat.com> Signed-off-by:
Oliver Upton <oupton@google.com> Message-Id: <20210916181555.973085-6-oupton@google.com> Signed-off-by:
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Oliver Upton authored
vCPU file descriptors are abstracted away from test code in KVM selftests, meaning that tests cannot directly access a vCPU's device attributes. Add helpers that tests can use to get at vCPU device attributes. Reviewed-by:
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Oliver Upton authored
The KVM_CREATE_DEVICE and KVM_{GET,SET}_DEVICE_ATTR ioctls are defined to return a value of zero on success. As such, tighten the assertions in the helper functions to only pass if the return code is zero. Suggested-by: -
Oliver Upton authored
Add a selftest for the new KVM clock UAPI that was introduced. Ensure that the KVM clock is consistent between userspace and the guest, and that the difference in realtime will only ever cause the KVM clock to advance forward. Cc: Andrew Jones <drjones@redhat.com> Signed-off-by:
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Oliver Upton authored
Copy over approximately clean versions of the pvclock headers into tools. Reconcile headers/symbols missing in tools that are unneeded. Signed-off-by:
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Oliver Upton authored
To date, VMM-directed TSC synchronization and migration has been a bit messy. KVM has some baked-in heuristics around TSC writes to infer if the VMM is attempting to synchronize. This is problematic, as it depends on host userspace writing to the guest's TSC within 1 second of the last write. A much cleaner approach to configuring the guest's views of the TSC is to simply migrate the TSC offset for every vCPU. Offsets are idempotent, and thus not subject to change depending on when the VMM actually reads/writes values from/to KVM. The VMM can then read the TSC once with KVM_GET_CLOCK to capture a (realtime, host_tsc) pair at the instant when the guest is paused. Cc: David Matlack <dmatlack@google.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by:
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Oliver Upton authored
Refactor kvm_synchronize_tsc to make a new function that allows callers to specify TSC parameters (offset, value, nanoseconds, etc.) explicitly for the sake of participating in TSC synchronization. Signed-off-by:
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Paolo Bonzini authored
Protect the reference point for kvmclock with a seqcount, so that kvmclock updates for all vCPUs can proceed in parallel. Xen runstate updates will also run in parallel and not bounce the kvmclock cacheline. Of the variables that were protected by pvclock_gtod_sync_lock, nr_vcpus_matched_tsc is different because it is updated outside pvclock_update_vm_gtod_copy and read inside it. Therefore, we need to keep it protected by a spinlock. In fact it must now be a raw spinlock, because pvclock_update_vm_gtod_copy, being the write-side of a seqcount, is non-preemptible. Since we already have tsc_write_lock which is a raw spinlock, we can just use tsc_write_lock as the lock that protects the write-side of the seqcount. Co-developed-by:
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Oliver Upton authored
Handling the migration of TSCs correctly is difficult, in part because Linux does not provide userspace with the ability to retrieve a (TSC, realtime) clock pair for a single instant in time. In lieu of a more convenient facility, KVM can report similar information in the kvm_clock structure. Provide userspace with a host TSC & realtime pair iff the realtime clock is based on the TSC. If userspace provides KVM_SET_CLOCK with a valid realtime value, advance the KVM clock by the amount of elapsed time. Do not step the KVM clock backwards, though, as it is a monotonic oscillator. Suggested-by:
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