linux-dev/arch/x86/kvm/mmu, branch master

KVM: x86/mmu: Block all page faults during kvm_zap_gfn_range()

2022-11-11T12:19:46Z

When zapping a GFN range, pass 0 => ALL_ONES for the to-be-invalidated range to effectively block all page faults while the zap is in-progress. The invalidation helpers take a host virtual address, whereas zapping a GFN obviously provides a guest physical address and with the wrong unit of measurement (frame vs. byte). Alternatively, KVM could walk all memslots to get the associated HVAs, but thanks to SMM, that would require multiple lookups. And practically speaking, kvm_zap_gfn_range() usage is quite rare and not a hot path, e.g. MTRR and CR0.CD are almost guaranteed to be done only on vCPU0 during boot, and APICv inhibits are similarly infrequent operations. Fixes: edb298c663fc ("KVM: x86/mmu: bump mmu notifier count in kvm_zap_gfn_range") Reported-by: Chao Peng Cc: stable@vger.kernel.org Cc: Maxim Levitsky Signed-off-by: Sean Christopherson Message-Id: <20221111001841.2412598-1-seanjc@google.com> Signed-off-by: Paolo Bonzini

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2022-10-09T16:39:55Z

Pull kvm updates from Paolo Bonzini: "The first batch of KVM patches, mostly covering x86. ARM: - Account stage2 page table allocations in memory stats x86: - Account EPT/NPT arm64 page table allocations in memory stats - Tracepoint cleanups/fixes for nested VM-Enter and emulated MSR accesses - Drop eVMCS controls filtering for KVM on Hyper-V, all known versions of Hyper-V now support eVMCS fields associated with features that are enumerated to the guest - Use KVM's sanitized VMCS config as the basis for the values of nested VMX capabilities MSRs - A myriad event/exception fixes and cleanups. Most notably, pending exceptions morph into VM-Exits earlier, as soon as the exception is queued, instead of waiting until the next vmentry. This fixed a longstanding issue where the exceptions would incorrecly become double-faults instead of triggering a vmexit; the common case of page-fault vmexits had a special workaround, but now it's fixed for good - A handful of fixes for memory leaks in error paths - Cleanups for VMREAD trampoline and VMX's VM-Exit assembly flow - Never write to memory from non-sleepable kvm_vcpu_check_block() - Selftests refinements and cleanups - Misc typo cleanups Generic: - remove KVM_REQ_UNHALT" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (94 commits) KVM: remove KVM_REQ_UNHALT KVM: mips, x86: do not rely on KVM_REQ_UNHALT KVM: x86: never write to memory from kvm_vcpu_check_block() KVM: x86: Don't snapshot pending INIT/SIPI prior to checking nested events KVM: nVMX: Make event request on VMXOFF iff INIT/SIPI is pending KVM: nVMX: Make an event request if INIT or SIPI is pending on VM-Enter KVM: SVM: Make an event request if INIT or SIPI is pending when GIF is set KVM: x86: lapic does not have to process INIT if it is blocked KVM: x86: Rename kvm_apic_has_events() to make it INIT/SIPI specific KVM: x86: Rename and expose helper to detect if INIT/SIPI are allowed KVM: nVMX: Make an event request when pending an MTF nested VM-Exit KVM: x86: make vendor code check for all nested events mailmap: Update Oliver's email address KVM: x86: Allow force_emulation_prefix to be written without a reload KVM: selftests: Add an x86-only test to verify nested exception queueing KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events() KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions KVM: x86: Morph pending exceptions to pending VM-Exits at queue time ...

KVM: x86/mmu: fix repeated words in comments

2022-09-26T16:03:02Z

Delete the redundant word 'to'. Signed-off-by: Jilin Yuan Link: https://lore.kernel.org/r/20220831125217.12313-1-yuanjilin@cdjrlc.com Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini

KVM: Add extra information in kvm_page_fault trace point

2022-09-26T16:02:30Z

Currently, kvm_page_fault trace point provide fault_address and error code. However it is not enough to find which cpu and instruction cause kvm_page_faults. So add vcpu id and instruction pointer in kvm_page_fault trace point. Cc: Baik Song An Cc: Hong Yeon Kim Cc: Taeung Song Cc: linuxgeek@linuxgeek.io Signed-off-by: Wonhyuk Yang Link: https://lore.kernel.org/r/20220510071001.87169-1-vvghjk1234@gmail.com Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini

KVM: x86/mmu: add missing update to max_mmu_rmap_size

2022-09-22T21:03:20Z

The update to statistic max_mmu_rmap_size is unintentionally removed by commit 4293ddb788c1 ("KVM: x86/mmu: Remove redundant spte present check in mmu_set_spte"). Add missing update to it or max_mmu_rmap_size will always be nonsensical 0. Fixes: 4293ddb788c1 ("KVM: x86/mmu: Remove redundant spte present check in mmu_set_spte") Signed-off-by: Miaohe Lin Message-Id: <20220907080657.42898-1-linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini

KVM: x86/mmu: count KVM mmu usage in secondary pagetable stats.

2022-08-30T14:41:12Z

Count the pages used by KVM mmu on x86 in memory stats under secondary pagetable stats (e.g. "SecPageTables" in /proc/meminfo) to give better visibility into the memory consumption of KVM mmu in a similar way to how normal user page tables are accounted. Add the inner helper in common KVM, ARM will also use it to count stats in a future commit. Signed-off-by: Yosry Ahmed Reviewed-by: Sean Christopherson Acked-by: Marc Zyngier # generic KVM changes Link: https://lore.kernel.org/r/20220823004639.2387269-3-yosryahmed@google.com Link: https://lore.kernel.org/r/20220823004639.2387269-4-yosryahmed@google.com [sean: squash x86 usage to workaround modpost issues] Signed-off-by: Sean Christopherson

KVM: x86/mmu: fix memoryleak in kvm_mmu_vendor_module_init()

2022-08-24T20:47:49Z

When register_shrinker() fails, KVM doesn't release the percpu counter kvm_total_used_mmu_pages leading to memoryleak. Fix this issue by calling percpu_counter_destroy() when register_shrinker() fails. Fixes: ab271bd4dfd5 ("x86: kvm: propagate register_shrinker return code") Signed-off-by: Miaohe Lin Link: https://lore.kernel.org/r/20220823063237.47299-1-linmiaohe@huawei.com [sean: tweak shortlog and changelog] Signed-off-by: Sean Christopherson

kvm: x86: mmu: Always flush TLBs when enabling dirty logging

2022-08-19T11:38:03Z

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 Message-Id: <20220810224939.2611160-1-junaids@google.com> Signed-off-by: Paolo Bonzini

kvm: x86: mmu: Drop the need_remote_flush() function

2022-08-19T11:38:02Z

This is only used by kvm_mmu_pte_write(), which no longer actually creates the new SPTE and instead just clears the old SPTE. So we just need to check if the old SPTE was shadow-present instead of calling need_remote_flush(). Hence we can drop this function. It was incomplete anyway as it didn't take access-tracking into account. This patch should not result in any functional change. Signed-off-by: Junaid Shahid Reviewed-by: David Matlack Reviewed-by: Sean Christopherson Message-Id: <20220723024316.2725328-1-junaids@google.com> Signed-off-by: Paolo Bonzini

KVM: Rename mmu_notifier_* to mmu_invalidate_*

2022-08-19T08:05:41Z

The motivation of this renaming is to make these variables and related helper functions less mmu_notifier bound and can also be used for non mmu_notifier based page invalidation. mmu_invalidate_* was chosen to better describe the purpose of 'invalidating' a page that those variables are used for. - mmu_notifier_seq/range_start/range_end are renamed to mmu_invalidate_seq/range_start/range_end. - mmu_notifier_retry{_hva} helper functions are renamed to mmu_invalidate_retry{_hva}. - mmu_notifier_count is renamed to mmu_invalidate_in_progress to avoid confusion with mn_active_invalidate_count. - While here, also update kvm_inc/dec_notifier_count() to kvm_mmu_invalidate_begin/end() to match the change for mmu_notifier_count. No functional change intended. Signed-off-by: Chao Peng Message-Id: <20220816125322.1110439-3-chao.p.peng@linux.intel.com> Signed-off-by: Paolo Bonzini