From nobody Wed Nov 27 02:36:27 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CDD7B1B4F14 for ; Mon, 14 Oct 2024 14:46:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917207; cv=none; b=PLw7lDYrwJLtKq3tMB9tALAw8Ho+lVQrdSoRGM1N8iLyBdVfPRsU47E3vgtQDEobzNXUAZm7V6i+wsy3CZn2hGhUD75FXW9qwhf9XZVUVFqfwULZS9I+ciwAa7eMwYhLCEdKcWp/00QLpF9rSypfDwrm7ZBL1rqmYQdwTz2zQ24= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917207; c=relaxed/simple; bh=6GrjvwYuZlk/X09sJDTfx4n347qy2DjePjJCHFD6X+g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KcWZz2sEC59a0BCggnbwaVXKTqdQmuhe8Tv6PIgfUzYYpCW8b09KpTjX/sD/fbmVOGhxFM8dZ0gGwVkbtKs6FtMoHyZZW16SjTFip6oLZQBga2M5dMmn+2aybgyokf79PRBOS/Qzm0MDPt1h/sH+XMGcpBsuQPIybLPVppNNY6U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=hzBgj/fk; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hzBgj/fk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728917205; 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=cvU7hgH0NcVyT2s8439e7eS1PoyrARDWsEuaW/yYTUo=; b=hzBgj/fkyAB0LsB+jzD2H3hcNlkuM1GoWefIPv9b24TGlHrkwOfjSEUpDp88CQ9qnB79Df oejHqqpjit+y40jIOuI070jjYLSQ3aq1XeE/Ok6y+r5GTg4PH5R3owUhx7htiivOjfYQvp EBXTAsdq5m0VmLkU0mRblJv8SbkpgXY= 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-651-d5FnqCvGOkSv9Gj83elS0A-1; Mon, 14 Oct 2024 10:46:41 -0400 X-MC-Unique: d5FnqCvGOkSv9Gj83elS0A-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 5198B19560A7; Mon, 14 Oct 2024 14:46:39 +0000 (UTC) Received: from t14s.cit.tum.de (unknown [10.22.32.146]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1ADD21955E8F; Mon, 14 Oct 2024 14:46:31 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet , Mario Casquero Subject: [PATCH v2 1/7] s390/kdump: implement is_kdump_kernel() Date: Mon, 14 Oct 2024 16:46:13 +0200 Message-ID: <20241014144622.876731-2-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" s390 currently always results in is_kdump_kernel() =3D=3D false, because it sets "elfcorehdr_addr =3D ELFCORE_ADDR_MAX;" early during setup_arch to deactivate the elfcorehdr=3D kernel parameter. Let's follow the powerpc example and implement our own logic. This is required for virtio-mem to reliably identify a kdump environment to not try hotplugging memory. Tested-by: Mario Casquero Signed-off-by: David Hildenbrand --- arch/s390/include/asm/kexec.h | 4 ++++ arch/s390/kernel/crash_dump.c | 6 ++++++ 2 files changed, 10 insertions(+) diff --git a/arch/s390/include/asm/kexec.h b/arch/s390/include/asm/kexec.h index 1bd08eb56d5f..bd20543515f5 100644 --- a/arch/s390/include/asm/kexec.h +++ b/arch/s390/include/asm/kexec.h @@ -94,6 +94,9 @@ void arch_kexec_protect_crashkres(void); =20 void arch_kexec_unprotect_crashkres(void); #define arch_kexec_unprotect_crashkres arch_kexec_unprotect_crashkres + +bool is_kdump_kernel(void); +#define is_kdump_kernel is_kdump_kernel #endif =20 #ifdef CONFIG_KEXEC_FILE @@ -107,4 +110,5 @@ int arch_kexec_apply_relocations_add(struct purgatory_i= nfo *pi, int arch_kimage_file_post_load_cleanup(struct kimage *image); #define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_clea= nup #endif + #endif /*_S390_KEXEC_H */ diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c index edae13416196..cca1827d3d2e 100644 --- a/arch/s390/kernel/crash_dump.c +++ b/arch/s390/kernel/crash_dump.c @@ -237,6 +237,12 @@ int remap_oldmem_pfn_range(struct vm_area_struct *vma,= unsigned long from, prot); } =20 +bool is_kdump_kernel(void) +{ + return oldmem_data.start && !is_ipl_type_dump(); +} +EXPORT_SYMBOL_GPL(is_kdump_kernel); + static const char *nt_name(Elf64_Word type) { const char *name =3D "LINUX"; --=20 2.46.1 From nobody Wed Nov 27 02:36:27 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38A3C1AB6EB for ; Mon, 14 Oct 2024 14:46:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917214; cv=none; b=C3mAGsv3PXmnwnDU5liXlpVBr7R9KJZyG5dOOmecEvDxWFTJRbWD/gIA+eYTKlUR4XhPYceTEpe3a0xAHHzpgki0FM4c8TFb6wmTFXs83fcM4M4CdbZp/L9n4p1s/sL/7V9CFPURxd0VNkYs+MXWPXXJ+CV3FfljHn1nBaLQc+Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; 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Mon, 14 Oct 2024 14:46:47 +0000 (UTC) Received: from t14s.cit.tum.de (unknown [10.22.32.146]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C0E941955E8F; Mon, 14 Oct 2024 14:46:39 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet Subject: [PATCH v2 2/7] Documentation: s390-diag.rst: make diag500 a generic KVM hypercall Date: Mon, 14 Oct 2024 16:46:14 +0200 Message-ID: <20241014144622.876731-3-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" Let's make it a generic KVM hypercall, allowing other subfunctions to be more independent of virtio. This is a preparation for documenting a new hypercall. Signed-off-by: David Hildenbrand --- Documentation/virt/kvm/s390/s390-diag.rst | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/Documentation/virt/kvm/s390/s390-diag.rst b/Documentation/virt= /kvm/s390/s390-diag.rst index ca85f030eb0b..d9b7c6cbc99e 100644 --- a/Documentation/virt/kvm/s390/s390-diag.rst +++ b/Documentation/virt/kvm/s390/s390-diag.rst @@ -35,15 +35,16 @@ DIAGNOSE function codes not specific to KVM, please ref= er to the documentation for the s390 hypervisors defining them. =20 =20 -DIAGNOSE function code 'X'500' - KVM virtio functions ------------------------------------------------------ +DIAGNOSE function code 'X'500' - KVM functions +---------------------------------------------- =20 -If the function code specifies 0x500, various virtio-related functions -are performed. +If the function code specifies 0x500, various KVM-specific functions +are performed, including virtio functions. =20 -General register 1 contains the virtio subfunction code. Supported -virtio subfunctions depend on KVM's userspace. Generally, userspace -provides either s390-virtio (subcodes 0-2) or virtio-ccw (subcode 3). +General register 1 contains the subfunction code. Supported subfunctions +depend on KVM's userspace. Regarding virtio subfunctions, generally +userspace provides either s390-virtio (subcodes 0-2) or virtio-ccw +(subcode 3). =20 Upon completion of the DIAGNOSE instruction, general register 2 contains the function's return code, which is either a return code or a subcode --=20 2.46.1 From nobody Wed Nov 27 02:36:27 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A3891ABEB7 for ; Mon, 14 Oct 2024 14:47:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917222; cv=none; b=oPjKfL3iZPSbn0s0OcJyINAr1Rki54D0sZ5eo35mzo2DtMH1409GHBm6gKXKbI655ezGDVVCdzooF/h8L20gQJTaqPsclW/GntAlPJsc3UZ1kEdFND7qcUJj8W91AUe6GAr38bjLjvyjLMTk6x2wAyukpWMMFIx+EOYPdrsYh2I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917222; c=relaxed/simple; bh=xo4mYAPPBob7V8aqw/TudOSIkweMqUBbW3QuvBb1KwE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TEaw54OC92I6J8x8vzr5OBSUuYnYTBxWMD7R9xR8DLRVNE1Db9+WFP85PGVkxdd7iWyKvBdMRIjN6n9W1w3lyGDgVWy3vyfuDZovi/VDPTaAs19GqN9yEAdkz6S5vBHY2dKmGrmT89AbOaXlbD4tPZ6nZyXdCrY33HGbBv3kRUU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=P3OkWOmk; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="P3OkWOmk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728917219; 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=4Os76zwoG6jFijiPcIPH9iCyJSDWZb0dHletZ1AI4lw=; b=P3OkWOmk+8hYvGlubXH4aK0BEF0tu2EXYLSAfRktVfpeBsUlGipXSV7jUkw9GmzsVUJnui 4i6R1+oeM4EL4R9Pm4BsIi/ya8jnSuDZyAXs2J9ovaBwXL60geb8tI4HM67U+xsNsgZ80J bhYRuK2eSOeZO7hmmwfkduXAC4QtVPA= Received: from mx-prod-mc-04.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-677-xXFMHelCOC6T9rvvopYX6w-1; Mon, 14 Oct 2024 10:46:56 -0400 X-MC-Unique: xXFMHelCOC6T9rvvopYX6w-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3DEEF19560BC; Mon, 14 Oct 2024 14:46:54 +0000 (UTC) Received: from t14s.cit.tum.de (unknown [10.22.32.146]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A52E41955E8F; Mon, 14 Oct 2024 14:46:47 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet Subject: [PATCH v2 3/7] Documentation: s390-diag.rst: document diag500(STORAGE LIMIT) subfunction Date: Mon, 14 Oct 2024 16:46:15 +0200 Message-ID: <20241014144622.876731-4-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" Let's document our new diag500 subfunction that can be implemented by userspace. Signed-off-by: David Hildenbrand --- Documentation/virt/kvm/s390/s390-diag.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/Documentation/virt/kvm/s390/s390-diag.rst b/Documentation/virt= /kvm/s390/s390-diag.rst index d9b7c6cbc99e..c69c6e0fa71b 100644 --- a/Documentation/virt/kvm/s390/s390-diag.rst +++ b/Documentation/virt/kvm/s390/s390-diag.rst @@ -77,6 +77,23 @@ Subcode 3 - virtio-ccw notification =20 See also the virtio standard for a discussion of this hypercall. =20 +Subcode 4 - storage-limit + Handled by userspace. + + After completion of the DIAGNOSE call, general register 2 will + contain the storage limit: the maximum physical address that might be + used for storage throughout the lifetime of the VM. + + The storage limit does not indicate currently usable storage, it may + include holes, standby storage and areas reserved for other means, such + as memory hotplug or virtio-mem devices. Other interfaces for detecting + actually usable storage, such as SCLP, must be used in conjunction with + this subfunction. + + Note that the storage limit can be larger, but never smaller than the + maximum storage address indicated by SCLP via the "maximum storage + increment" and the "increment size". + =20 DIAGNOSE function code 'X'501 - KVM breakpoint ---------------------------------------------- --=20 2.46.1 From nobody Wed Nov 27 02:36:27 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B13D71ABEB7 for ; Mon, 14 Oct 2024 14:47:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917231; cv=none; b=qWPLEqhdIpCsoDYMH2LPUUzBghVk5LBKvUihO+KkU9nigfZugsckqYQpUP6LhiMgMPszRw/uHgp6ZP4CDMAtn+utfgr6G01lEsPi8BtIjAv/jFg/hYb/H/G9wsRVEEwCkekmHooQoV/XPthmz7hxwQ4JbN5/NLOMIdyPPa81x8g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917231; c=relaxed/simple; bh=J9y0Z1um2rl9fvxub0OMeLMEU7e/L9CepdPZo9alnDU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GaVugAmeH21AOzzLD9bBdHDoUFF3amzfA8YDwpV40a+BkWi8qpDx00XtNsfNp6IhfmLIFMPBffS1kXG4mNTyzBsHBxulfGuB5pkIFZlWAOtcuj3r6KMWCm/aGus6XGVKj0BkYLytnIUVWJNAq4jF1y3N5jdLmcBdAwpy7+Qpydw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LChlaCoX; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LChlaCoX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728917227; 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=jQUFS3Gk+h07Pyzz5SlEqpZc8ARhWR4alZK+qKnRzag=; b=LChlaCoXnin1F9fJhHSfeliU3O7Vc/VGbtpjhxXPQf/9H8yfMfxjV30SZ6xZA1NGUQPto5 MyCEhryFxvwophO0mvb+FPe9Rd3Fw+pyErG6Be/A/LVd3eCxgEbuAFxiJJasqLWEOk/NKr bpWA1KkrFzVySUbvfTu5G/bRrvgiDj4= Received: from mx-prod-mc-04.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-453-gZo0ZuGeNOKYSOCW-Fnf8w-1; Mon, 14 Oct 2024 10:47:04 -0400 X-MC-Unique: gZo0ZuGeNOKYSOCW-Fnf8w-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3D72E1955F42; Mon, 14 Oct 2024 14:47:02 +0000 (UTC) Received: from t14s.cit.tum.de (unknown [10.22.32.146]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CDE7B1955E93; Mon, 14 Oct 2024 14:46:54 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet , Mario Casquero Subject: [PATCH v2 4/7] s390/physmem_info: query diag500(STORAGE LIMIT) to support QEMU/KVM memory devices Date: Mon, 14 Oct 2024 16:46:16 +0200 Message-ID: <20241014144622.876731-5-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" To support memory devices under QEMU/KVM, such as virtio-mem, we have to prepare our kernel virtual address space accordingly and have to know the highest possible physical memory address we might see later: the storage limit. The good old SCLP interface is not suitable for this use case. In particular, memory owned by memory devices has no relationship to storage increments, it is always detected using the device driver, and unaware OSes (no driver) must never try making use of that memory. Consequently this memory is located outside of the "maximum storage increment"-indicated memory range. Let's use our new diag500 STORAGE_LIMIT subcode to query this storage limit that can exceed the "maximum storage increment", and use the existing interfaces (i.e., SCLP) to obtain information about the initial memory that is not owned+managed by memory devices. If a hypervisor does not support such memory devices, the address exposed through diag500 STORAGE_LIMIT will correspond to the maximum storage increment exposed through SCLP. To teach kdump on s390 to include memory owned by memory devices, there will be ways to query the relevant memory ranges from the device via a driver running in special kdump mode (like virtio-mem already implements to filter /proc/vmcore access so we don't end up reading from unplugged device blocks). Tested-by: Mario Casquero Signed-off-by: David Hildenbrand Reviewed-by: Alexander Gordeev --- arch/s390/boot/physmem_info.c | 46 ++++++++++++++++++++++++++-- arch/s390/include/asm/physmem_info.h | 3 ++ 2 files changed, 46 insertions(+), 3 deletions(-) diff --git a/arch/s390/boot/physmem_info.c b/arch/s390/boot/physmem_info.c index 1d131a81cb8b..fb4e66e80fd8 100644 --- a/arch/s390/boot/physmem_info.c +++ b/arch/s390/boot/physmem_info.c @@ -109,6 +109,38 @@ static int diag260(void) return 0; } =20 +static int diag500_storage_limit(unsigned long *max_physmem_end) +{ + register unsigned long __nr asm("1") =3D 0x4; + register unsigned long __storage_limit asm("2") =3D 0; + unsigned long reg1, reg2; + psw_t old; + + asm volatile( + " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n" + " epsw %[reg1],%[reg2]\n" + " st %[reg1],0(%[psw_pgm])\n" + " st %[reg2],4(%[psw_pgm])\n" + " larl %[reg1],1f\n" + " stg %[reg1],8(%[psw_pgm])\n" + " diag 2,4,0x500\n" + "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n" + : [reg1] "=3D&d" (reg1), + [reg2] "=3D&a" (reg2), + "+&d" (__storage_limit), + "=3DQ" (get_lowcore()->program_new_psw), + "=3DQ" (old) + : [psw_old] "a" (&old), + [psw_pgm] "a" (&get_lowcore()->program_new_psw), + "d" (__nr) + : "memory"); + if (!__storage_limit) + return -EINVAL; + /* convert inclusive end to exclusive end. */ + *max_physmem_end =3D __storage_limit + 1; + return 0; +} + static int tprot(unsigned long addr) { unsigned long reg1, reg2; @@ -157,7 +189,9 @@ unsigned long detect_max_physmem_end(void) { unsigned long max_physmem_end =3D 0; =20 - if (!sclp_early_get_memsize(&max_physmem_end)) { + if (!diag500_storage_limit(&max_physmem_end)) { + physmem_info.info_source =3D MEM_DETECT_DIAG500_STOR_LIMIT; + } else if (!sclp_early_get_memsize(&max_physmem_end)) { physmem_info.info_source =3D MEM_DETECT_SCLP_READ_INFO; } else { max_physmem_end =3D search_mem_end(); @@ -170,11 +204,17 @@ void detect_physmem_online_ranges(unsigned long max_p= hysmem_end) { if (!sclp_early_read_storage_info()) { physmem_info.info_source =3D MEM_DETECT_SCLP_STOR_INFO; + return; } else if (!diag260()) { physmem_info.info_source =3D MEM_DETECT_DIAG260; - } else if (max_physmem_end) { - add_physmem_online_range(0, max_physmem_end); + return; + } else if (physmem_info.info_source =3D=3D MEM_DETECT_DIAG500_STOR_LIMIT)= { + max_physmem_end =3D 0; + if (!sclp_early_get_memsize(&max_physmem_end)) + physmem_info.info_source =3D MEM_DETECT_SCLP_READ_INFO; } + if (max_physmem_end) + add_physmem_online_range(0, max_physmem_end); } =20 void physmem_set_usable_limit(unsigned long limit) diff --git a/arch/s390/include/asm/physmem_info.h b/arch/s390/include/asm/p= hysmem_info.h index f45cfc8bc233..51b68a43e195 100644 --- a/arch/s390/include/asm/physmem_info.h +++ b/arch/s390/include/asm/physmem_info.h @@ -9,6 +9,7 @@ enum physmem_info_source { MEM_DETECT_NONE =3D 0, MEM_DETECT_SCLP_STOR_INFO, MEM_DETECT_DIAG260, + MEM_DETECT_DIAG500_STOR_LIMIT, MEM_DETECT_SCLP_READ_INFO, MEM_DETECT_BIN_SEARCH }; @@ -107,6 +108,8 @@ static inline const char *get_physmem_info_source(void) return "sclp storage info"; case MEM_DETECT_DIAG260: return "diag260"; + case MEM_DETECT_DIAG500_STOR_LIMIT: + return "diag500 storage limit"; case MEM_DETECT_SCLP_READ_INFO: return "sclp read info"; 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Mon, 14 Oct 2024 10:47:12 -0400 X-MC-Unique: aFyz8o1aOxaBv2Y6jRkjlg-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E358A195608B; Mon, 14 Oct 2024 14:47:09 +0000 (UTC) Received: from t14s.cit.tum.de (unknown [10.22.32.146]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B54F31955E93; Mon, 14 Oct 2024 14:47:02 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet , Mario Casquero Subject: [PATCH v2 5/7] virtio-mem: s390 support Date: Mon, 14 Oct 2024 16:46:17 +0200 Message-ID: <20241014144622.876731-6-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" Now that s390 code is prepared for memory devices that reside above the maximum storage increment exposed through SCLP, everything is in place to unlock virtio-mem support. As virtio-mem in Linux currently supports logically onlining/offlining memory in pageblock granularity, we have an effective hot(un)plug granularity of 1 MiB on s390. As virito-mem adds/removes individual Linux memory blocks (256MB), we will currently never use gigantic pages in the identity mapping. It is worth noting that neither storage keys nor storage attributes (e.g., data / nodat) are touched when onlining memory blocks, which is good because we are not supposed to touch these parts for unplugged device blocks that are logically offline in Linux. We will currently never initialize storage keys for virtio-mem memory -- IOW, storage_key_init_range() is never called. It could be added in the future when plugging device blocks. But as that function essentially does nothing without modifying the code (changing PAGE_DEFAULT_ACC), that's just fine for now. kexec should work as intended and just like on other architectures that support virtio-mem: we will never place kexec binaries on virtio-mem memory, and never indicate virtio-mem memory to the 2nd kernel. The device driver in the 2nd kernel can simply reset the device -- turning all memory unplugged, to then start plugging memory and adding them to Linux, without causing trouble because the memory is already used elsewhere. The special s390 kdump mode, whereby the 2nd kernel creates the ELF core header, won't currently dump virtio-mem memory. The virtio-mem driver has a special kdump mode, from where we can detect memory ranges to dump. Based on this, support for dumping virtio-mem memory can be added in the future fairly easily. Acked-by: Michael S. Tsirkin Tested-by: Mario Casquero Signed-off-by: David Hildenbrand --- drivers/virtio/Kconfig | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 42a48ac763ee..fb320eea70fe 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -122,7 +122,7 @@ config VIRTIO_BALLOON =20 config VIRTIO_MEM tristate "Virtio mem driver" - depends on X86_64 || ARM64 || RISCV + depends on X86_64 || ARM64 || RISCV || S390 depends on VIRTIO depends on MEMORY_HOTPLUG depends on MEMORY_HOTREMOVE @@ -132,11 +132,11 @@ config VIRTIO_MEM This driver provides access to virtio-mem paravirtualized memory devices, allowing to hotplug and hotunplug memory. =20 - This driver currently only supports x86-64 and arm64. 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Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet , Mario Casquero Subject: [PATCH v2 6/7] lib/Kconfig.debug: default STRICT_DEVMEM to "y" on s390 Date: Mon, 14 Oct 2024 16:46:18 +0200 Message-ID: <20241014144622.876731-7-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" virtio-mem currently depends on !DEVMEM | STRICT_DEVMEM. Let's default STRICT_DEVMEM to "y" just like we do for arm64 and x86. There could be ways in the future to filter access to virtio-mem device memory even without STRICT_DEVMEM, but for now let's just keep it simple. Tested-by: Mario Casquero Signed-off-by: David Hildenbrand Acked-by: Heiko Carstens --- lib/Kconfig.debug | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 7315f643817a..e7a917540e2a 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1905,7 +1905,7 @@ config STRICT_DEVMEM bool "Filter access to /dev/mem" depends on MMU && DEVMEM depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED - default y if PPC || X86 || ARM64 + default y if PPC || X86 || ARM64 || S390 help If this option is disabled, you allow userspace (root) access to all of memory, including kernel and userspace memory. 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Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Jonathan Corbet , Mario Casquero Subject: [PATCH v2 7/7] s390/sparsemem: reduce section size to 128 MiB Date: Mon, 14 Oct 2024 16:46:19 +0200 Message-ID: <20241014144622.876731-8-david@redhat.com> In-Reply-To: <20241014144622.876731-1-david@redhat.com> References: <20241014144622.876731-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" Ever since commit 421c175c4d609 ("[S390] Add support for memory hot-add.") we've been using a section size of 256 MiB on s390 and 32 MiB on s390. Before that, we were using a section size of 32 MiB on both architectures. Likely the reason was that we'd expect a storage increment size of 256 MiB under z/VM back then. As we didn't support memory blocks spanning multiple memory sections, we would have had to handle having multiple memory blocks for a single storage increment, which complicates things. Although that issue reappeared with even bigger storage increment sizes later, nowadays we have memory blocks that can span multiple memory sections and we avoid any such issue completely. Now that we have a new mechanism to expose additional memory to a VM -- virtio-mem -- reduce the section size to 128 MiB to allow for more flexibility and reduce the metadata overhead when dealing with hot(un)plug granularity smaller than 256 MiB. 128 MiB has been used by x86-64 since the very beginning. arm64 with 4k base pages switched to 128 MiB as well: it's just big enough on these architectures to allows for using a huge page (2 MiB) in the vmemmap in sane setups with sizeof(struct page) =3D=3D 64 bytes and a huge page mapping in the direct mapping, while still allowing for small hot(un)plug granularity. For s390, we could even switch to a 64 MiB section size, as our huge page size is 1 MiB: but the smaller the section size, the more sections we'll have to manage especially on bigger machines. Making it consistent with x86-64 and arm64 feels like te right thing for now. Note that the smallest memory hot(un)plug granularity is also limited by the memory block size, determined by extracting the memory increment size from SCLP. Under QEMU/KVM, implementing virtio-mem, we expose 0; therefore, we'll end up with a memory block size of 128 MiB with a 128 MiB section size. Tested-by: Mario Casquero Signed-off-by: David Hildenbrand Acked-by: Heiko Carstens --- arch/s390/include/asm/sparsemem.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/include/asm/sparsemem.h b/arch/s390/include/asm/spar= semem.h index c549893602ea..ff628c50afac 100644 --- a/arch/s390/include/asm/sparsemem.h +++ b/arch/s390/include/asm/sparsemem.h @@ -2,7 +2,7 @@ #ifndef _ASM_S390_SPARSEMEM_H #define _ASM_S390_SPARSEMEM_H =20 -#define SECTION_SIZE_BITS 28 +#define SECTION_SIZE_BITS 27 #define MAX_PHYSMEM_BITS CONFIG_MAX_PHYSMEM_BITS =20 #endif /* _ASM_S390_SPARSEMEM_H */ --=20 2.46.1