From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:42786) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hG1e0-0004rt-B8 for qemu-devel@nongnu.org; Mon, 15 Apr 2019 09:27:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hG1dy-00059s-Ew for qemu-devel@nongnu.org; Mon, 15 Apr 2019 09:27:32 -0400 From: Igor Mammedov Date: Mon, 15 Apr 2019 15:27:22 +0200 Message-Id: <1555334842-195718-6-git-send-email-imammedo@redhat.com> In-Reply-To: <1555334842-195718-1-git-send-email-imammedo@redhat.com> References: <1555334842-195718-1-git-send-email-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH v1 5/5] s390: do not call memory_region_allocate_system_memory() multiple times List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Richard Henderson , Helge Deller , =?UTF-8?q?Herv=C3=A9=20Poussineau?= , David Gibson , Cornelia Huck , Halil Pasic , Christian Borntraeger , David Hildenbrand , Artyom Tarasenko , Mark Cave-Ayland , qemu-ppc@nongnu.org, qemu-s390x@nongnu.org s390 was trying to solve limited memslot size issue by abusing memory_region_allocate_system_memory(), which breaks API contract where the function might be called only once. s390 should have used memory aliases to fragment inital memory into smaller chunks to satisfy KVM's memslot limitation. But its a bit late now, since allocated pieces are transfered in migration stream separately, so it's not possible to just replace broken layout with correct one. Previous patch made MemoryRegion alases migratable and this patch switches to use them to split big initial RAM chunk into smaller pieces up to KVM_SLOT_MAX_BYTES each and registers aliases for migration. Signed-off-by: Igor Mammedov --- A don't have access to a suitable system to test it, so I've simulated it with smaller chunks on x84 host. Ping-pong migration between old and new QEMU worked fine. KVM part should be fine as memslots using mapped MemoryRegions (in this case it would be aliases) as far as I know but is someone could test it on big enough host it would be nice. --- hw/s390x/s390-virtio-ccw.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index d11069b..12ca3a9 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -161,20 +161,30 @@ static void virtio_ccw_register_hcalls(void) static void s390_memory_init(ram_addr_t mem_size) { MemoryRegion *sysmem = get_system_memory(); + MemoryRegion *ram = g_new(MemoryRegion, 1); ram_addr_t chunk, offset = 0; unsigned int number = 0; gchar *name; /* allocate RAM for core */ + memory_region_allocate_system_memory(ram, NULL, "s390.whole.ram", mem_size); + /* + * memory_region_allocate_system_memory() registers allocated RAM for + * migration, however for compat reasons the RAM should be passed over + * as RAMBlocks of the size upto KVM_SLOT_MAX_BYTES. So unregister just + * allocated RAM so it won't be migrated directly. Aliases will take + * of segmenting RAM into legacy chunks. + */ + vmstate_unregister_ram(ram, NULL); name = g_strdup_printf("s390.ram"); while (mem_size) { - MemoryRegion *ram = g_new(MemoryRegion, 1); - uint64_t size = mem_size; + MemoryRegion *alias = g_new(MemoryRegion, 1); /* KVM does not allow memslots >= 8 TB */ - chunk = MIN(size, KVM_SLOT_MAX_BYTES); - memory_region_allocate_system_memory(ram, NULL, name, chunk); - memory_region_add_subregion(sysmem, offset, ram); + chunk = MIN(mem_size, KVM_SLOT_MAX_BYTES); + memory_region_init_alias(alias, NULL, name, ram, offset, chunk); + vmstate_register_ram_global(alias); + memory_region_add_subregion(sysmem, offset, alias); mem_size -= chunk; offset += chunk; g_free(name); -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61306C10F0E for ; Mon, 15 Apr 2019 13:34:27 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3237F20833 for ; Mon, 15 Apr 2019 13:34:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3237F20833 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:50342 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hG1kg-0000xV-He for qemu-devel@archiver.kernel.org; Mon, 15 Apr 2019 09:34:26 -0400 Received: from eggs.gnu.org ([209.51.188.92]:42786) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hG1e0-0004rt-B8 for qemu-devel@nongnu.org; Mon, 15 Apr 2019 09:27:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hG1dy-00059s-Ew for qemu-devel@nongnu.org; Mon, 15 Apr 2019 09:27:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34504) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hG1dw-00058E-FX; Mon, 15 Apr 2019 09:27:28 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BA5BE307EA98; Mon, 15 Apr 2019 13:27:26 +0000 (UTC) Received: from dell-r430-03.lab.eng.brq.redhat.com (dell-r430-03.lab.eng.brq.redhat.com [10.37.153.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id E7D0A1001DDD; Mon, 15 Apr 2019 13:27:21 +0000 (UTC) From: Igor Mammedov To: qemu-devel@nongnu.org Date: Mon, 15 Apr 2019 15:27:22 +0200 Message-Id: <1555334842-195718-6-git-send-email-imammedo@redhat.com> In-Reply-To: <1555334842-195718-1-git-send-email-imammedo@redhat.com> References: <1555334842-195718-1-git-send-email-imammedo@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Mon, 15 Apr 2019 13:27:26 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v1 5/5] s390: do not call memory_region_allocate_system_memory() multiple times X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-ppc@nongnu.org, David Hildenbrand , Helge Deller , Cornelia Huck , Mark Cave-Ayland , Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, =?UTF-8?q?Herv=C3=A9=20Poussineau?= , Paolo Bonzini , Richard Henderson , Artyom Tarasenko , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="UTF-8" Message-ID: <20190415132722.uA3bHhHsvD3dRhugzZcUZTr6NlkQHIYfaZzOt4DFuoE@z> s390 was trying to solve limited memslot size issue by abusing memory_region_allocate_system_memory(), which breaks API contract where the function might be called only once. s390 should have used memory aliases to fragment inital memory into smaller chunks to satisfy KVM's memslot limitation. But its a bit late now, since allocated pieces are transfered in migration stream separately, so it's not possible to just replace broken layout with correct one. Previous patch made MemoryRegion alases migratable and this patch switches to use them to split big initial RAM chunk into smaller pieces up to KVM_SLOT_MAX_BYTES each and registers aliases for migration. Signed-off-by: Igor Mammedov --- A don't have access to a suitable system to test it, so I've simulated it with smaller chunks on x84 host. Ping-pong migration between old and new QEMU worked fine. KVM part should be fine as memslots using mapped MemoryRegions (in this case it would be aliases) as far as I know but is someone could test it on big enough host it would be nice. --- hw/s390x/s390-virtio-ccw.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index d11069b..12ca3a9 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -161,20 +161,30 @@ static void virtio_ccw_register_hcalls(void) static void s390_memory_init(ram_addr_t mem_size) { MemoryRegion *sysmem = get_system_memory(); + MemoryRegion *ram = g_new(MemoryRegion, 1); ram_addr_t chunk, offset = 0; unsigned int number = 0; gchar *name; /* allocate RAM for core */ + memory_region_allocate_system_memory(ram, NULL, "s390.whole.ram", mem_size); + /* + * memory_region_allocate_system_memory() registers allocated RAM for + * migration, however for compat reasons the RAM should be passed over + * as RAMBlocks of the size upto KVM_SLOT_MAX_BYTES. So unregister just + * allocated RAM so it won't be migrated directly. Aliases will take + * of segmenting RAM into legacy chunks. + */ + vmstate_unregister_ram(ram, NULL); name = g_strdup_printf("s390.ram"); while (mem_size) { - MemoryRegion *ram = g_new(MemoryRegion, 1); - uint64_t size = mem_size; + MemoryRegion *alias = g_new(MemoryRegion, 1); /* KVM does not allow memslots >= 8 TB */ - chunk = MIN(size, KVM_SLOT_MAX_BYTES); - memory_region_allocate_system_memory(ram, NULL, name, chunk); - memory_region_add_subregion(sysmem, offset, ram); + chunk = MIN(mem_size, KVM_SLOT_MAX_BYTES); + memory_region_init_alias(alias, NULL, name, ram, offset, chunk); + vmstate_register_ram_global(alias); + memory_region_add_subregion(sysmem, offset, alias); mem_size -= chunk; offset += chunk; g_free(name); -- 2.7.4