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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Feb 17, 2025 at 1:28 PM Philippe Mathieu-Daudé wrote: > > qemu-system-x86_64 -m 512 -nographic -object sev-snp-guest,reduced-phys-bits=48,id=sev0 \ > > -M q35,kernel-irqchip=split,confidential-guest-support=sev0 > > qemu-system-x86_64: ../system/physmem.c:1871: ram_block_add: Assertion `kvm_enabled()' failed. > > I'd expect sev-snp-guest to bail out early enough. > > Is a KVM-enabled check in sev_snp_guest_instance_init() missing? instance_init cannot do any check (it cannot fail). There is a check for whether sev_common_kvm_init succeeded: if (machine->cgs && !machine->cgs->ready) { error_setg(errp, "accelerator does not support confidential guest %s", object_get_typename(OBJECT(machine->cgs))); exit(1); } but that doesn't help if the system/physmem.c code is reached before qemu_machine_creation_done(), for example in qemu_init_board(). Likewise, you cannot fal in host_memory_backend_init() because that's also an instance_init callback. > > - assert(kvm_enabled()); > > + if (!kvm_enabled()) { > > + error_setg(errp, "cannot set up private guest memory for %s: KVM required", > > + object_get_typename(OBJECT(current_machine->cgs))); > > Common code should be SW vs HW accel, so IMHO your check > should go within sev_snp_guest_instance_init(), removing > the assertion here. That said I have no clue about SEV. This code is outside accel/kvm or target/*/kvn, but it is not quite common code. A few lines below you have: new_block->guest_memfd = kvm_create_guest_memfd(new_block->max_length, 0, errp); Paolo