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| author | Will Deacon <will@kernel.org> | 2026-03-30 15:48:10 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2026-03-30 16:58:07 +0100 |
| commit | f0877a1455cc6a93be14e4da741ce26ac0d6ca6d (patch) | |
| tree | 8201f05e8e5b8f49c2e5b474c9dfba532d0669b0 | |
| parent | 7250533ad2c1f0e49567077e9b0f66b0349b357e (diff) | |
| download | linux-f0877a1455cc6a93be14e4da741ce26ac0d6ca6d.tar.gz linux-f0877a1455cc6a93be14e4da741ce26ac0d6ca6d.zip | |
KVM: arm64: Prevent unsupported memslot operations on protected VMs
Protected VMs do not support deleting or moving memslots after first
run nor do they support read-only or dirty logging.
Return -EPERM to userspace if such an operation is attempted.
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-10-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/mmu.c | 13 | ||||
| -rw-r--r-- | arch/arm64/kvm/pkvm.c | 6 |
2 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 5e7821fe0fc4..b3cc5dfe5723 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2414,6 +2414,19 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, hva_t hva, reg_end; int ret = 0; + if (kvm_vm_is_protected(kvm)) { + /* Cannot modify memslots once a pVM has run. */ + if (pkvm_hyp_vm_is_created(kvm) && + (change == KVM_MR_DELETE || change == KVM_MR_MOVE)) { + return -EPERM; + } + + if (new && + new->flags & (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)) { + return -EPERM; + } + } + if (change != KVM_MR_CREATE && change != KVM_MR_MOVE && change != KVM_MR_FLAGS_ONLY) return 0; diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index dd93dfdfe52d..94b70eb80aa8 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -192,10 +192,16 @@ int pkvm_create_hyp_vm(struct kvm *kvm) { int ret = 0; + /* + * Synchronise with kvm_arch_prepare_memory_region(), as we + * prevent memslot modifications on a pVM that has been run. + */ + mutex_lock(&kvm->slots_lock); mutex_lock(&kvm->arch.config_lock); if (!pkvm_hyp_vm_is_created(kvm)) ret = __pkvm_create_hyp_vm(kvm); mutex_unlock(&kvm->arch.config_lock); + mutex_unlock(&kvm->slots_lock); return ret; } |