From patchwork Wed Jun 10 11:54:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11597605 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CA48714B7 for ; Wed, 10 Jun 2020 11:55:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4E5C2072E for ; Wed, 10 Jun 2020 11:55:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Y5DJo/Kv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728755AbgFJLzB (ORCPT ); Wed, 10 Jun 2020 07:55:01 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:56266 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728730AbgFJLzA (ORCPT ); Wed, 10 Jun 2020 07:55:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591790097; 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=u3TnvMHIMVg+ynIb51APci4iCUQNAE73bAVqqwa7/LQ=; b=Y5DJo/KvQb9Bq3Li7DSELsUYe4HWkDYPSzXoUgdDC0hcB+yW6UF6vXTkjrVojw3o77A6Bg 1bAwFmi/FgKOMen0nDuGNSs7WBWds5cRLdpEfuJIasYmkNDJbc5S5BQwCXBxkVABbtYZft hcoa41/Iih6PcfGBtsfdiRqoCz/5bF8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-1-kUj70tKQP2ug4p5YQ87IUg-1; Wed, 10 Jun 2020 07:54:52 -0400 X-MC-Unique: kUj70tKQP2ug4p5YQ87IUg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 453A1107ACCA; Wed, 10 Jun 2020 11:54:51 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-42.ams2.redhat.com [10.36.114.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id EE79C5D9D3; Wed, 10 Jun 2020 11:54:39 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, qemu-s390x@nongnu.org, Richard Henderson , Paolo Bonzini , "Dr . David Alan Gilbert" , Eduardo Habkost , "Michael S . Tsirkin" , David Hildenbrand , Cornelia Huck , Alex Williamson , Christian Borntraeger , Tony Krowiak , Halil Pasic , Pierre Morel , Eric Farman Subject: [PATCH v4 02/21] vfio: Convert to ram_block_discard_disable() Date: Wed, 10 Jun 2020 13:54:00 +0200 Message-Id: <20200610115419.51688-3-david@redhat.com> In-Reply-To: <20200610115419.51688-1-david@redhat.com> References: <20200610115419.51688-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org VFIO is (except devices without a physical IOMMU or some mediated devices) incompatible with discarding of RAM. The kernel will pin basically all VM memory. Let's convert to ram_block_discard_disable(), which can now fail, in contrast to qemu_balloon_inhibit(). Leave "x-balloon-allowed" named as it is for now. Cc: Cornelia Huck Cc: Alex Williamson Cc: Christian Borntraeger Cc: Tony Krowiak Cc: Halil Pasic Cc: Pierre Morel Cc: Eric Farman Signed-off-by: David Hildenbrand Reviewed-by: Tony Krowiak Acked-by: Cornelia Huck --- hw/vfio/ap.c | 10 +++---- hw/vfio/ccw.c | 11 ++++---- hw/vfio/common.c | 53 +++++++++++++++++++---------------- hw/vfio/pci.c | 6 ++-- include/hw/vfio/vfio-common.h | 4 +-- 5 files changed, 45 insertions(+), 39 deletions(-) diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c index 95564c17ed..d0b1bc7581 100644 --- a/hw/vfio/ap.c +++ b/hw/vfio/ap.c @@ -105,12 +105,12 @@ static void vfio_ap_realize(DeviceState *dev, Error **errp) vapdev->vdev.dev = dev; /* - * vfio-ap devices operate in a way compatible with - * memory ballooning, as no pages are pinned in the host. - * This needs to be set before vfio_get_device() for vfio common to - * handle the balloon inhibitor. + * vfio-ap devices operate in a way compatible discarding of memory in + * RAM blocks, as no pages are pinned in the host. This needs to be + * set before vfio_get_device() for vfio common to handle + * ram_block_discard_disable(). */ - vapdev->vdev.balloon_allowed = true; + vapdev->vdev.ram_block_discard_allowed = true; ret = vfio_get_device(vfio_group, mdevid, &vapdev->vdev, errp); if (ret) { diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 63406184d2..82857f1615 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -418,12 +418,13 @@ static void vfio_ccw_get_device(VFIOGroup *group, VFIOCCWDevice *vcdev, /* * All vfio-ccw devices are believed to operate in a way compatible with - * memory ballooning, ie. pages pinned in the host are in the current - * working set of the guest driver and therefore never overlap with pages - * available to the guest balloon driver. This needs to be set before - * vfio_get_device() for vfio common to handle the balloon inhibitor. + * discarding of memory in RAM blocks, ie. pages pinned in the host are + * in the current working set of the guest driver and therefore never + * overlap e.g., with pages available to the guest balloon driver. This + * needs to be set before vfio_get_device() for vfio common to handle + * ram_block_discard_disable(). */ - vcdev->vdev.balloon_allowed = true; + vcdev->vdev.ram_block_discard_allowed = true; if (vfio_get_device(group, vcdev->cdev.mdevid, &vcdev->vdev, errp)) { goto out_err; diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 0b3593b3c0..33357140b8 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -33,7 +33,6 @@ #include "qemu/error-report.h" #include "qemu/main-loop.h" #include "qemu/range.h" -#include "sysemu/balloon.h" #include "sysemu/kvm.h" #include "sysemu/reset.h" #include "trace.h" @@ -1215,31 +1214,36 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, space = vfio_get_address_space(as); /* - * VFIO is currently incompatible with memory ballooning insofar as the + * VFIO is currently incompatible with discarding of RAM insofar as the * madvise to purge (zap) the page from QEMU's address space does not * interact with the memory API and therefore leaves stale virtual to * physical mappings in the IOMMU if the page was previously pinned. We - * therefore add a balloon inhibit for each group added to a container, + * therefore set discarding broken for each group added to a container, * whether the container is used individually or shared. This provides * us with options to allow devices within a group to opt-in and allow - * ballooning, so long as it is done consistently for a group (for instance + * discarding, so long as it is done consistently for a group (for instance * if the device is an mdev device where it is known that the host vendor * driver will never pin pages outside of the working set of the guest - * driver, which would thus not be ballooning candidates). + * driver, which would thus not be discarding candidates). * * The first opportunity to induce pinning occurs here where we attempt to * attach the group to existing containers within the AddressSpace. If any - * pages are already zapped from the virtual address space, such as from a - * previous ballooning opt-in, new pinning will cause valid mappings to be + * pages are already zapped from the virtual address space, such as from + * previous discards, new pinning will cause valid mappings to be * re-established. Likewise, when the overall MemoryListener for a new * container is registered, a replay of mappings within the AddressSpace * will occur, re-establishing any previously zapped pages as well. * - * NB. Balloon inhibiting does not currently block operation of the - * balloon driver or revoke previously pinned pages, it only prevents - * calling madvise to modify the virtual mapping of ballooned pages. + * Especially virtio-balloon is currently only prevented from discarding + * new memory, it will not yet set ram_block_discard_set_required() and + * therefore, neither stops us here or deals with the sudden memory + * consumption of inflated memory. */ - qemu_balloon_inhibit(true); + ret = ram_block_discard_disable(true); + if (ret) { + error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken"); + return ret; + } QLIST_FOREACH(container, &space->containers, next) { if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) { @@ -1405,7 +1409,7 @@ close_fd_exit: close(fd); put_space_exit: - qemu_balloon_inhibit(false); + ram_block_discard_disable(false); vfio_put_address_space(space); return ret; @@ -1526,8 +1530,8 @@ void vfio_put_group(VFIOGroup *group) return; } - if (!group->balloon_allowed) { - qemu_balloon_inhibit(false); + if (!group->ram_block_discard_allowed) { + ram_block_discard_disable(false); } vfio_kvm_device_del_group(group); vfio_disconnect_container(group); @@ -1565,22 +1569,23 @@ int vfio_get_device(VFIOGroup *group, const char *name, } /* - * Clear the balloon inhibitor for this group if the driver knows the - * device operates compatibly with ballooning. Setting must be consistent - * per group, but since compatibility is really only possible with mdev - * currently, we expect singleton groups. + * Set discarding of RAM as not broken for this group if the driver knows + * the device operates compatibly with discarding. Setting must be + * consistent per group, but since compatibility is really only possible + * with mdev currently, we expect singleton groups. */ - if (vbasedev->balloon_allowed != group->balloon_allowed) { + if (vbasedev->ram_block_discard_allowed != + group->ram_block_discard_allowed) { if (!QLIST_EMPTY(&group->device_list)) { - error_setg(errp, - "Inconsistent device balloon setting within group"); + error_setg(errp, "Inconsistent setting of support for discarding " + "RAM (e.g., balloon) within group"); close(fd); return -1; } - if (!group->balloon_allowed) { - group->balloon_allowed = true; - qemu_balloon_inhibit(false); + if (!group->ram_block_discard_allowed) { + group->ram_block_discard_allowed = true; + ram_block_discard_disable(false); } } diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 342dd6b912..c33c11b7e4 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -2796,7 +2796,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) } /* - * Mediated devices *might* operate compatibly with memory ballooning, but + * Mediated devices *might* operate compatibly with discarding of RAM, but * we cannot know for certain, it depends on whether the mdev vendor driver * stays in sync with the active working set of the guest driver. Prevent * the x-balloon-allowed option unless this is minimally an mdev device. @@ -2809,7 +2809,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) trace_vfio_mdev(vdev->vbasedev.name, is_mdev); - if (vdev->vbasedev.balloon_allowed && !is_mdev) { + if (vdev->vbasedev.ram_block_discard_allowed && !is_mdev) { error_setg(errp, "x-balloon-allowed only potentially compatible " "with mdev devices"); vfio_put_group(group); @@ -3163,7 +3163,7 @@ static Property vfio_pci_dev_properties[] = { VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), DEFINE_PROP_BOOL("x-balloon-allowed", VFIOPCIDevice, - vbasedev.balloon_allowed, false), + vbasedev.ram_block_discard_allowed, false), DEFINE_PROP_BOOL("x-no-kvm-intx", VFIOPCIDevice, no_kvm_intx, false), DEFINE_PROP_BOOL("x-no-kvm-msi", VFIOPCIDevice, no_kvm_msi, false), DEFINE_PROP_BOOL("x-no-kvm-msix", VFIOPCIDevice, no_kvm_msix, false), diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index fd564209ac..c78f3ff559 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -108,7 +108,7 @@ typedef struct VFIODevice { bool reset_works; bool needs_reset; bool no_mmap; - bool balloon_allowed; + bool ram_block_discard_allowed; VFIODeviceOps *ops; unsigned int num_irqs; unsigned int num_regions; @@ -128,7 +128,7 @@ typedef struct VFIOGroup { QLIST_HEAD(, VFIODevice) device_list; QLIST_ENTRY(VFIOGroup) next; QLIST_ENTRY(VFIOGroup) container_next; - bool balloon_allowed; + bool ram_block_discard_allowed; } VFIOGroup; typedef struct VFIODMABuf {