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Thu, 21 May 2026 07:36:31 -0700 (PDT) Date: Thu, 21 May 2026 15:36:25 +0100 In-Reply-To: <20260521143626.1005660-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20260521143626.1005660-1-vdonnefort@google.com> X-Mailer: git-send-email 2.54.0.746.g67dd491aae-goog Message-ID: <20260521143626.1005660-3-vdonnefort@google.com> Subject: [RESEND v3 2/3] KVM: arm64: Fix __pkvm_init_vm error path From: Vincent Donnefort To: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kernel-team@android.com, qperret@google.com, tabba@google.com, Vincent Donnefort , Sashiko Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260521_073633_458201_1FC215FD X-CRM114-Status: GOOD ( 10.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In the unlikely case where insert_vm_table_entry fails, __pkvm_init_vm release the memory donated by the host for the PGD, but as the stage-2 is still set-up the hypervisor keeps a refcount on those pages, effectively leaking the references. Fix the rollback with the newly added kvm_guest_destroy_stage2(). Fixes: 256b4668cd89 ("KVM: arm64: Introduce separate hypercalls for pKVM VM reservation and initialization") Reported-by: Sashiko Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 3cbfae0e3dda..4f2b871199cb 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -56,6 +56,7 @@ int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot p int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id); int kvm_host_prepare_stage2(void *pgt_pool_base); int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd); +void kvm_guest_destroy_stage2(struct pkvm_hyp_vm *vm); void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt); int hyp_pin_shared_mem(void *from, void *to); diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index fa447d400b71..986e0ac1f2d8 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -305,16 +305,21 @@ int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd) return 0; } +void kvm_guest_destroy_stage2(struct pkvm_hyp_vm *vm) +{ + guest_lock_component(vm); + kvm_pgtable_stage2_destroy(&vm->pgt); + vm->kvm.arch.mmu.pgd_phys = 0ULL; + guest_unlock_component(vm); +} + void reclaim_pgtable_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc) { struct hyp_page *page; void *addr; /* Dump all pgtable pages in the hyp_pool */ - guest_lock_component(vm); - kvm_pgtable_stage2_destroy(&vm->pgt); - vm->kvm.arch.mmu.pgd_phys = 0ULL; - guest_unlock_component(vm); + kvm_guest_destroy_stage2(vm); /* Drain the hyp_pool into the memcache */ addr = hyp_alloc_pages(&vm->pool, 0); diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index eb1c10120f9f..3b2c4fbc34d8 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -853,10 +853,12 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva, /* Must be called last since this publishes the VM. */ ret = insert_vm_table_entry(handle, hyp_vm); if (ret) - goto err_remove_mappings; + goto err_destroy_stage2; return 0; +err_destroy_stage2: + kvm_guest_destroy_stage2(hyp_vm); err_remove_mappings: unmap_donated_memory(hyp_vm, vm_size); unmap_donated_memory(pgd, pgd_size); -- 2.54.0.746.g67dd491aae-goog