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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 On 9/18/26 15:49, Paolo Bonzini wrote: > [cover letter copied from v2 - sorry for the very quick turnaround > but it's pointless to ask for reviews with the issues reported by > sashiko] > > This series introduces a mechanism to let userspace block read, > write or execute access to individual GFNs via KVM's memory > attribute mechanism, and have them reported via KVM_EXIT_MEMORY_FAULT. > It is mostly the work of Nicolas Saenz Julienne, with my working > consisting in reorganization, code cleanup, and using the recently > revamped MMU code (ACC_* masks and kvm_page_format). > > KVM needs to check the attributes anytime KVM takes GPAs as input for any > action initiated by the guest; if the memory attributes are incompatible > with such action, it should be stopped. This means that there are quite > a lot of cases to handle. While some families of functions can be > handled in one step, there are simply many places that do memory access. > > Along the way, the patches fix some issues in the memory attributes code, > that surfaced due to having more than one attribute. > > Paolo The remaining AI review issues (https://sashiko.dev/#/patchset/20260918135030.171564-2-pbonzini%40redhat.com) are simple or intentional with one exception: - patch 21 - missing xas.xa_node == XAS_BOUNDS check, easy enough - patch 26 - missing EFAULT returns from the emulator, need to look at it and write tests - patch 28 - i think it should be fine, but it can also be fixed with cond_resched() if needed - patch 31 - WRITE_ONCE can be used for completeness If desired, patches 1 and 5 can be applied to stable and/or 7.2-rc. Paolo > > v2->v3 is just a bunch of sashiko fixes: > - new patch "KVM: x86/hyperv: do not overwrite hc->ingpa for slow > SIGNAL_EVENT hypercall" > - rewritten "KVM: apply nGPA->GPA translation to KVM_HC_CLOCK_PAIRING" > to handle cross-patch accesses > - rewrite choice of KVM_FILTER_SHARED/KVM_FILTER_PRIVATE prior to > setting memory attributes; even though the previous version worked, > it relied on not having any attribute at all for has_private_mem VMs > - fix WARN_ON_ONCE/WARN_ONCE confusion > - fix loongarch compilation > - new (not really satisfactory_ patch "KVM: Take memory protections into > account for __kvm_vcpu_map" > - fix incorrect NOT in "KVM: x86/mmu: Do not prefetch sptes on gfns backed > by memory attributes" > - do not use kvm_mmu_prepare_memory_fault_exit() for attribute exits on > PTEs > - new patch "KVM: let kvm_arch_post_set_memory_attributes drop mmu_lock" > - testcase fixes > > Anish Moorthy (1): > KVM: Define and communicate KVM_EXIT_MEMORY_FAULT RWX flags to > userspace > > Nicolas Saenz Julienne (12): > KVM: selftests: Take into account mixed memory fault flags > KVM: x86/mmu: Init memslot hugepage information for non-private_mem > VMs too > KVM: Introduce NR/NW/NX memory attributes > KVM: Include memory protections in result of gfn->hva conversion > KVM: Take memory protections into account for memory read/write/fetch > KVM: Encapsulate memattrs array into anonymous struct > KVM: Introduce a generation number for memory attributes > KVM: Take memory protections into account for accesses with cached > gfn->hva > KVM: pfncache: Fail to refresh if it contains memory protections > KVM: x86/mmu: Do not prefetch sptes on gfns backed by memory > attributes > KVM: x86/mmu: Take memory protection attributes into account during > faults > KVM: x86/mmu: Issue memory fault exit if walk failed due to memory > attribute > > Paolo Bonzini (18): > KVM: x86/hyperv: do not overwrite hc->ingpa for slow SIGNAL_EVENT > hypercall > KVM: selftests: Test address translation for Hyper-V direct L2 > hypercalls > KVM: apply nGPA->GPA translation to KVM_HC_CLOCK_PAIRING > KVM: x86: Introduce memory fault on invalid hypercalls reads/writes > KVM: selftests: test hypercall memory fault exits > KVM: x86/mmu: intersect writability from __kvm_faultin_pfn with > fault->map_writable > KVM: x86/mmu: Extend map_writable to a full ACC_* mask > KVM: pass kvm == NULL case to kvm_arch_has_private_mem > KVM: adjust for presence of more than one attribute > KVM: Introduce kvm_fetch_guest_page() and use it for x86 > KVM: Take memory protections into account for __kvm_vcpu_map > KVM: loongarch: do full validity check on the gfn-to-hva cache > KVM: Introduce kvm_check_gen()/kvm_memslots_check_gen() > KVM: let kvm_arch_post_set_memory_attributes drop mmu_lock > KVM: x86/mmu: Obsolete all roots if memattr contains gPTEs > KVM: x86: selftests: Introduce memory protection attributes test > KVM: x86: selftests: Introduce memory attributes PTE test > KVM: x86: selftests: Introduce memory attributes side-channel tests > > Documentation/virt/kvm/api.rst | 38 +- > arch/loongarch/kvm/vcpu.c | 12 +- > arch/x86/include/asm/kvm_host.h | 4 +- > arch/x86/kvm/Kconfig | 4 +- > arch/x86/kvm/hyperv.c | 172 +++++-- > arch/x86/kvm/mmu/mmu.c | 183 +++++-- > arch/x86/kvm/mmu/mmu_internal.h | 21 +- > arch/x86/kvm/mmu/mmutrace.h | 36 ++ > arch/x86/kvm/mmu/paging_tmpl.h | 25 +- > arch/x86/kvm/mmu/spte.c | 12 +- > arch/x86/kvm/mmu/spte.h | 13 +- > arch/x86/kvm/mmu/tdp_mmu.c | 2 +- > arch/x86/kvm/x86.c | 66 ++- > include/linux/kvm_host.h | 128 ++++- > include/linux/kvm_types.h | 6 +- > include/trace/events/kvm.h | 14 +- > include/uapi/linux/kvm.h | 7 + > tools/include/uapi/linux/kvm.h | 3 + > tools/testing/selftests/kvm/Makefile.kvm | 2 + > .../testing/selftests/kvm/include/kvm_util.h | 32 +- > .../selftests/kvm/include/x86/processor.h | 1 + > .../testing/selftests/kvm/lib/x86/processor.c | 5 + > .../testing/selftests/kvm/memory_attributes.c | 453 ++++++++++++++++++ > tools/testing/selftests/kvm/x86/hcall_fault.c | 246 ++++++++++ > .../testing/selftests/kvm/x86/hyperv_evmcs.c | 16 +- > .../selftests/kvm/x86/hyperv_svm_test.c | 15 +- > .../selftests/kvm/x86/memory_attributes.c | 415 ++++++++++++++++ > .../kvm/x86/private_mem_kvm_exits_test.c | 6 +- > virt/kvm/kvm_main.c | 271 +++++++++-- > virt/kvm/pfncache.c | 30 +- > 30 files changed, 2027 insertions(+), 211 deletions(-) > create mode 100644 tools/testing/selftests/kvm/memory_attributes.c > create mode 100644 tools/testing/selftests/kvm/x86/hcall_fault.c > create mode 100644 tools/testing/selftests/kvm/x86/memory_attributes.c >