From patchwork Tue Sep 10 17:58:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13799178 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 80A45EDE9AC for ; Tue, 10 Sep 2024 17:59:21 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1so58n-0006hi-NH; Tue, 10 Sep 2024 13:59:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1so58m-0006YW-0L for qemu-devel@nongnu.org; Tue, 10 Sep 2024 13:59:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1so58k-0006QV-Ay for qemu-devel@nongnu.org; Tue, 10 Sep 2024 13:58:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1725991137; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cECBk1qPAy/kFJQbJli+ig8bld14E32zOLZX1hTjPnw=; b=S9n+LsJQ1H3HRm2Sp0+xX6ZK9sMLAiyoq7u8cHHZM9PDIAF0eBo3tB7evibGh5vG6g7F/R 9GuftQk0vIREgol64ziJZo24KJXRIQo+4ntMObFS3rcPnx3dLGG3Xmo6GLBD3+K13NIVh8 wZP2pIbpIlpye+SLWNdYQVyiOvooapA= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-450-43twLiD5OiSpbQqui4OpKg-1; Tue, 10 Sep 2024 13:58:54 -0400 X-MC-Unique: 43twLiD5OiSpbQqui4OpKg-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AF208195394C; Tue, 10 Sep 2024 17:58:52 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.22.32.182]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 423BB19560AD; Tue, 10 Sep 2024 17:58:47 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: qemu-s390x@nongnu.org, David Hildenbrand , Paolo Bonzini , Thomas Huth , Halil Pasic , Christian Borntraeger , Eric Farman , Richard Henderson , Ilya Leoshkevich , Janosch Frank , "Michael S. Tsirkin" , Cornelia Huck Subject: [PATCH v1 07/14] s390x/s390-hypercall: introduce DIAG500 STORAGE_LIMIT Date: Tue, 10 Sep 2024 19:58:02 +0200 Message-ID: <20240910175809.2135596-8-david@redhat.com> In-Reply-To: <20240910175809.2135596-1-david@redhat.com> References: <20240910175809.2135596-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.145, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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 A guest OS that supports memory hotplug / memory devices must during boot be aware of the maximum possible physical memory address that it might have to handle at a later stage during its runtime For example, the maximum possible memory address might be required to prepare the kernel virtual address space accordingly (e.g., select page table hierarchy depth). On s390x there is currently no such mechanism that is compatible with paravirtualized memory devices, because the whole SCLP interface was designed around the idea of "storage increments" and "standby memory". Paravirtualized memory devices we want to support, such as virtio-mem, have no intersection with any of that, but could co-exist with them in the future if ever needed. In particular, a guest OS must never detect and use device memory without the help of a proper device driver. Device memory must not be exposed in any firmware-provided memory map (SCLP or diag260 on s390x). For this reason, these memory devices will be places in memory *above* the "maximum storage increment" exposed via SCLP. Let's provide a new diag500 subcode to query the memory limit determined in s390_memory_init(). Signed-off-by: David Hildenbrand Reviewed-by: Thomas Huth --- hw/s390x/s390-hypercall.c | 3 +++ hw/s390x/s390-hypercall.h | 1 + 2 files changed, 4 insertions(+) diff --git a/hw/s390x/s390-hypercall.c b/hw/s390x/s390-hypercall.c index f09e8a1d81..ac48fc0961 100644 --- a/hw/s390x/s390-hypercall.c +++ b/hw/s390x/s390-hypercall.c @@ -68,6 +68,9 @@ int handle_diag_500(CPUS390XState *env) case DIAG500_VIRTIO_CCW_NOTIFY: env->regs[2] = handle_virtio_ccw_notify(env->regs[2], env->regs[3]); return 0; + case DIAG500_STORAGE_LIMIT: + env->regs[2] = s390_get_memory_limit() - 1; + return 0; default: return -EINVAL; } diff --git a/hw/s390x/s390-hypercall.h b/hw/s390x/s390-hypercall.h index b7ac29f444..f0ca62bcbb 100644 --- a/hw/s390x/s390-hypercall.h +++ b/hw/s390x/s390-hypercall.h @@ -18,6 +18,7 @@ #define DIAG500_VIRTIO_RESET 1 /* legacy */ #define DIAG500_VIRTIO_SET_STATUS 2 /* legacy */ #define DIAG500_VIRTIO_CCW_NOTIFY 3 /* KVM_S390_VIRTIO_CCW_NOTIFY */ +#define DIAG500_STORAGE_LIMIT 4 int handle_diag_500(CPUS390XState *env);