From: Christoph Schlameuss schlameuss@linux.ibm.com

mainline inclusion from mainline-v6.11-rc1 commit 7816e58967d0e6cadce05c8540b47ed027dc2499 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAKQ5E CVE: CVE-2024-43819

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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This change rejects the KVM_SET_USER_MEMORY_REGION and KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM. This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and would thus result in a null pointer dereference further in. Memory management needs to be performed in userspace and using the ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP.

Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION and KVM_SET_USER_MEMORY_REGION2.

Signed-off-by: Christoph Schlameuss schlameuss@linux.ibm.com Fixes: 27e0393f15fc ("KVM: s390: ucontrol: per vcpu address spaces") Reviewed-by: Claudio Imbrenda imbrenda@linux.ibm.com Link: https://lore.kernel.org/r/20240624095902.29375-1-schlameuss@linux.ibm.com Signed-off-by: Janosch Frank frankja@linux.ibm.com [frankja@linux.ibm.com: commit message spelling fix, subject prefix fix] Message-ID: 20240624095902.29375-1-schlameuss@linux.ibm.com

Conflicts: arch/s390/kvm/kvm-s390.c Documentation/virt/kvm/api.rst [Commit cf5b486922dc ("KVM: s390: Use "new" memslot instead of userspace memory region") add definition of "size"; Commit b8f8d190fa8f ("KVM: arm64: Document the behaviour of S1PTW faults on RO memslots") add some descriptions before KVM_SET_TSS_ADDR; Commit bb58b90b1a8f ("KVM: Introduce KVM_SET_USER_MEMORY_REGION2") introduce the description of KVM_SET_USER_MEMORY_REGION2.] Signed-off-by: Li Lingfeng lilingfeng3@huawei.com --- Documentation/virt/kvm/api.rst | 5 +++++ arch/s390/kvm/kvm-s390.c | 3 +++ 2 files changed, 8 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 4980cab552f3..5d55487e2eb2 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -1331,6 +1331,11 @@ It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl. The KVM_SET_MEMORY_REGION does not allow fine grained control over memory allocation and is deprecated.

+S390: +^^^^^ + +Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set. +Returns -EINVAL if called on a protected VM.

4.36 KVM_SET_TSS_ADDR --------------------- diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index d7c216ada386..b9b883ef47be 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4992,6 +4992,9 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, const struct kvm_userspace_memory_region *mem, enum kvm_mr_change change) { + if (kvm_is_ucontrol(kvm)) + return -EINVAL; + /* A few sanity checks. We can have memory slots which have to be located/ended at a segment boundary (1MB). The memory in userland is ok to be fragmented into various different vmas. It is okay to mmap()