From patchwork Mon Jul 30 23:13:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 10549691 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 59762157D for ; Mon, 30 Jul 2018 23:14:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3662D29FDA for ; Mon, 30 Jul 2018 23:14:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 292F529FFB; Mon, 30 Jul 2018 23:14:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D4B7129FDA for ; Mon, 30 Jul 2018 23:14:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732179AbeGaAvR (ORCPT ); Mon, 30 Jul 2018 20:51:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54058 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732010AbeGaAvR (ORCPT ); Mon, 30 Jul 2018 20:51:17 -0400 Received: from smtp.corp.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4E839307D861; Mon, 30 Jul 2018 23:14:01 +0000 (UTC) Received: from gimli.home (ovpn-116-35.phx2.redhat.com [10.3.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id DAD483083322; Mon, 30 Jul 2018 23:13:46 +0000 (UTC) Subject: [PATCH v2 1/4] balloon: Allow nested inhibits From: Alex Williamson To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, peterx@redhat.com, cohuck@redhat.com, mst@redhat.com, david@redhat.com Date: Mon, 30 Jul 2018 17:13:46 -0600 Message-ID: <153299242656.14411.14216251294160965283.stgit@gimli.home> In-Reply-To: <153299204130.14411.11438396195753743913.stgit@gimli.home> References: <153299204130.14411.11438396195753743913.stgit@gimli.home> User-Agent: StGit/0.18-136-gffd7-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Mon, 30 Jul 2018 23:14:01 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP A simple true/false internal state does not allow multiple users. Fix this within the existing interface by converting to a counter, so long as the counter is elevated, ballooning is inhibited. Signed-off-by: Alex Williamson Reviewed-by: David Hildenbrand Reviewed-by: Peter Xu Reviewed-by: Cornelia Huck --- balloon.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/balloon.c b/balloon.c index 6bf0a9681377..931987983858 100644 --- a/balloon.c +++ b/balloon.c @@ -26,6 +26,7 @@ #include "qemu/osdep.h" #include "qemu-common.h" +#include "qemu/atomic.h" #include "exec/cpu-common.h" #include "sysemu/kvm.h" #include "sysemu/balloon.h" @@ -37,16 +38,22 @@ static QEMUBalloonEvent *balloon_event_fn; static QEMUBalloonStatus *balloon_stat_fn; static void *balloon_opaque; -static bool balloon_inhibited; +static int balloon_inhibit_count; bool qemu_balloon_is_inhibited(void) { - return balloon_inhibited; + return atomic_read(&balloon_inhibit_count) > 0; } void qemu_balloon_inhibit(bool state) { - balloon_inhibited = state; + if (state) { + atomic_inc(&balloon_inhibit_count); + } else { + atomic_dec(&balloon_inhibit_count); + } + + assert(atomic_read(&balloon_inhibit_count) >= 0); } static bool have_balloon(Error **errp) From patchwork Mon Jul 30 23:14:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 10549693 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8F8D715E2 for ; Mon, 30 Jul 2018 23:14:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6CA0C29FDA for ; Mon, 30 Jul 2018 23:14:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6105B29FFB; Mon, 30 Jul 2018 23:14:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F0C1929FDA for ; Mon, 30 Jul 2018 23:14:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732098AbeGaAvh (ORCPT ); Mon, 30 Jul 2018 20:51:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52806 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731994AbeGaAvh (ORCPT ); Mon, 30 Jul 2018 20:51:37 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A355E4E907; Mon, 30 Jul 2018 23:14:16 +0000 (UTC) Received: from gimli.home (ovpn-116-35.phx2.redhat.com [10.3.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id A47B4600C0; Mon, 30 Jul 2018 23:14:06 +0000 (UTC) Subject: [PATCH v2 2/4] kvm: Use inhibit to prevent ballooning without synchronous mmu From: Alex Williamson To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, peterx@redhat.com, cohuck@redhat.com, mst@redhat.com, david@redhat.com Date: Mon, 30 Jul 2018 17:14:06 -0600 Message-ID: <153299244635.14411.14909988281437283403.stgit@gimli.home> In-Reply-To: <153299204130.14411.11438396195753743913.stgit@gimli.home> References: <153299204130.14411.11438396195753743913.stgit@gimli.home> User-Agent: StGit/0.18-136-gffd7-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 30 Jul 2018 23:14:20 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Remove KVM specific tests in balloon_page(), instead marking ballooning as inhibited without KVM_CAP_SYNC_MMU support. Signed-off-by: Alex Williamson Reviewed-by: David Hildenbrand Reviewed-by: Peter Xu Reviewed-by: Cornelia Huck --- accel/kvm/kvm-all.c | 4 ++++ hw/virtio/virtio-balloon.c | 4 +--- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index eb7db92a5e3b..38f468d8e2b1 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -39,6 +39,7 @@ #include "trace.h" #include "hw/irq.h" #include "sysemu/sev.h" +#include "sysemu/balloon.h" #include "hw/boards.h" @@ -1698,6 +1699,9 @@ static int kvm_init(MachineState *ms) s->many_ioeventfds = kvm_check_many_ioeventfds(); s->sync_mmu = !!kvm_vm_check_extension(kvm_state, KVM_CAP_SYNC_MMU); + if (!s->sync_mmu) { + qemu_balloon_inhibit(true); + } return 0; diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 1f7a87f09429..b5425080c5fb 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -21,7 +21,6 @@ #include "hw/mem/pc-dimm.h" #include "sysemu/balloon.h" #include "hw/virtio/virtio-balloon.h" -#include "sysemu/kvm.h" #include "exec/address-spaces.h" #include "qapi/error.h" #include "qapi/qapi-events-misc.h" @@ -36,8 +35,7 @@ static void balloon_page(void *addr, int deflate) { - if (!qemu_balloon_is_inhibited() && (!kvm_enabled() || - kvm_has_sync_mmu())) { + if (!qemu_balloon_is_inhibited()) { qemu_madvise(addr, BALLOON_PAGE_SIZE, deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); } From patchwork Mon Jul 30 23:14:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 10549695 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 42A9D15E2 for ; Mon, 30 Jul 2018 23:14:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1E88629FDA for ; Mon, 30 Jul 2018 23:14:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1019E29FFB; Mon, 30 Jul 2018 23:14:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9DABA29FDA for ; Mon, 30 Jul 2018 23:14:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732117AbeGaAvs (ORCPT ); Mon, 30 Jul 2018 20:51:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42914 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732027AbeGaAvs (ORCPT ); Mon, 30 Jul 2018 20:51:48 -0400 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4C6073082A23; Mon, 30 Jul 2018 23:14:32 +0000 (UTC) Received: from gimli.home (ovpn-116-35.phx2.redhat.com [10.3.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 051DA308BDA6; Mon, 30 Jul 2018 23:14:21 +0000 (UTC) Subject: [PATCH v2 3/4] vfio: Inhibit ballooning based on group attachment to a container From: Alex Williamson To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, peterx@redhat.com, cohuck@redhat.com, mst@redhat.com, david@redhat.com Date: Mon, 30 Jul 2018 17:14:21 -0600 Message-ID: <153299246170.14411.6197545037372422542.stgit@gimli.home> In-Reply-To: <153299204130.14411.11438396195753743913.stgit@gimli.home> References: <153299204130.14411.11438396195753743913.stgit@gimli.home> User-Agent: StGit/0.18-136-gffd7-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 30 Jul 2018 23:14:32 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We use a VFIOContainer to associate an AddressSpace to one or more VFIOGroups. The VFIOContainer represents the DMA context for that AdressSpace for those VFIOGroups and is synchronized to changes in that AddressSpace via a MemoryListener. For IOMMU backed devices, maintaining the DMA context for a VFIOGroup generally involves pinning a host virtual address in order to create a stable host physical address and then mapping a translation from the associated guest physical address to that host physical address into the IOMMU. While the above maintains the VFIOContainer synchronized to the QEMU memory API of the VM, memory ballooning occurs outside of that API. Inflating the memory balloon (ie. cooperatively capturing pages from the guest for use by the host) simply uses MADV_DONTNEED to "zap" pages from QEMU's host virtual address space. The page pinning and IOMMU mapping above remains in place, negating the host's ability to reuse the page, but the host virtual to host physical mapping of the page is invalidated outside of QEMU's memory API. When the balloon is later deflated, attempting to cooperatively return pages to the guest, the page is simply freed by the guest balloon driver, allowing it to be used in the guest and incurring a page fault when that occurs. The page fault maps a new host physical page backing the existing host virtual address, meanwhile the VFIOContainer still maintains the translation to the original host physical address. At this point the guest vCPU and any assigned devices will map different host physical addresses to the same guest physical address. Badness. The IOMMU typically does not have page level granularity with which it can track this mapping without also incurring inefficiencies in using page size mappings throughout. MMU notifiers in the host kernel also provide indicators for invalidating the mapping on balloon inflation, not for updating the mapping when the balloon is deflated. For these reasons we assume a default behavior that the mapping of each VFIOGroup into the VFIOContainer is incompatible with memory ballooning and increment the balloon inhibitor to match the attached VFIOGroups. Signed-off-by: Alex Williamson Reviewed-by: Peter Xu --- hw/vfio/common.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/vfio/common.c b/hw/vfio/common.c index fb396cf00ac4..4881b691a659 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -32,6 +32,7 @@ #include "hw/hw.h" #include "qemu/error-report.h" #include "qemu/range.h" +#include "sysemu/balloon.h" #include "sysemu/kvm.h" #include "trace.h" #include "qapi/error.h" @@ -1049,6 +1050,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, group->container = container; QLIST_INSERT_HEAD(&container->group_list, group, container_next); vfio_kvm_device_add_group(group); + qemu_balloon_inhibit(true); return 0; } } @@ -1198,6 +1200,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, } vfio_kvm_device_add_group(group); + qemu_balloon_inhibit(true); QLIST_INIT(&container->group_list); QLIST_INSERT_HEAD(&space->containers, container, next); @@ -1222,6 +1225,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, listener_release_exit: QLIST_REMOVE(group, container_next); QLIST_REMOVE(container, next); + qemu_balloon_inhibit(false); vfio_kvm_device_del_group(group); vfio_listener_release(container); @@ -1352,6 +1356,7 @@ void vfio_put_group(VFIOGroup *group) return; } + qemu_balloon_inhibit(false); vfio_kvm_device_del_group(group); vfio_disconnect_container(group); QLIST_REMOVE(group, next); From patchwork Mon Jul 30 23:14:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 10549699 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 565DB15E2 for ; Mon, 30 Jul 2018 23:14:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3249429FDA for ; Mon, 30 Jul 2018 23:14:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 26A1829FFB; Mon, 30 Jul 2018 23:14:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 82A0229FDA for ; Mon, 30 Jul 2018 23:14:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732163AbeGaAwD (ORCPT ); Mon, 30 Jul 2018 20:52:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52918 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732027AbeGaAwD (ORCPT ); Mon, 30 Jul 2018 20:52:03 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6A4254E907; Mon, 30 Jul 2018 23:14:46 +0000 (UTC) Received: from gimli.home (ovpn-116-35.phx2.redhat.com [10.3.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id A04FB16C1C; Mon, 30 Jul 2018 23:14:37 +0000 (UTC) Subject: [PATCH v2 4/4] vfio/ccw/pci: Allow devices to opt-in for ballooning From: Alex Williamson To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, peterx@redhat.com, cohuck@redhat.com, mst@redhat.com, david@redhat.com Date: Mon, 30 Jul 2018 17:14:37 -0600 Message-ID: <153299247733.14411.6837517320997223920.stgit@gimli.home> In-Reply-To: <153299204130.14411.11438396195753743913.stgit@gimli.home> References: <153299204130.14411.11438396195753743913.stgit@gimli.home> User-Agent: StGit/0.18-136-gffd7-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 30 Jul 2018 23:14:46 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If a vfio assigned device makes use of a physical IOMMU, then memory ballooning is necessarily inhibited due to the page pinning, lack of page level granularity at the IOMMU, and sufficient notifiers to both remove the page on balloon inflation and add it back on deflation. However, not all devices are backed by a physical IOMMU. In the case of mediated devices, if a vendor driver is well synchronized with the guest driver, such that only pages actively used by the guest driver are pinned by the host mdev vendor driver, then there should be no overlap between pages available for the balloon driver and pages actively in use by the device. Under these conditions, ballooning should be safe. vfio-ccw devices are always mediated devices and always operate under the constraints above. Therefore we can consider all vfio-ccw devices as balloon compatible. The situation is far from straightforward with vfio-pci. These devices can be physical devices with physical IOMMU backing or mediated devices where it is unknown whether a physical IOMMU is in use or whether the vendor driver is well synchronized to the working set of the guest driver. The safest approach is therefore to assume all vfio-pci devices are incompatible with ballooning, but allow user opt-in should they have further insight into mediated devices. Signed-off-by: Alex Williamson --- hw/vfio/ccw.c | 9 +++++++++ hw/vfio/common.c | 23 ++++++++++++++++++++++- hw/vfio/pci.c | 26 +++++++++++++++++++++++++- hw/vfio/trace-events | 1 + include/hw/vfio/vfio-common.h | 2 ++ 5 files changed, 59 insertions(+), 2 deletions(-) diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 351b305e1ae7..40e7b5623e69 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -349,6 +349,15 @@ static void vfio_ccw_get_device(VFIOGroup *group, VFIOCCWDevice *vcdev, } } + /* + * All vfio-ccw devices are believed to operate compatibly 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. + */ + vcdev->vdev.balloon_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 4881b691a659..ef5f4b77548a 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -1356,7 +1356,9 @@ void vfio_put_group(VFIOGroup *group) return; } - qemu_balloon_inhibit(false); + if (!group->balloon_allowed) { + qemu_balloon_inhibit(false); + } vfio_kvm_device_del_group(group); vfio_disconnect_container(group); QLIST_REMOVE(group, next); @@ -1392,6 +1394,25 @@ int vfio_get_device(VFIOGroup *group, const char *name, return ret; } + /* + * 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. + */ + if (vbasedev->balloon_allowed != group->balloon_allowed) { + if (!QLIST_EMPTY(&group->device_list)) { + error_setg(errp, + "Inconsistent device balloon setting within group"); + return -1; + } + + if (!group->balloon_allowed) { + group->balloon_allowed = true; + qemu_balloon_inhibit(false); + } + } + vbasedev->fd = fd; vbasedev->group = group; QLIST_INSERT_HEAD(&group->device_list, vbasedev, next); diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 6cbb8fa0549d..056f3a887a8f 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -2804,12 +2804,13 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev); VFIODevice *vbasedev_iter; VFIOGroup *group; - char *tmp, group_path[PATH_MAX], *group_name; + char *tmp, *subsys, group_path[PATH_MAX], *group_name; Error *err = NULL; ssize_t len; struct stat st; int groupid; int i, ret; + bool is_mdev; if (!vdev->vbasedev.sysfsdev) { if (!(~vdev->host.domain || ~vdev->host.bus || @@ -2869,6 +2870,27 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) } } + /* + * Mediated devices *might* operate compatibly with memory ballooning, 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. + */ + tmp = g_strdup_printf("%s/subsystem", vdev->vbasedev.sysfsdev); + subsys = realpath(tmp, NULL); + g_free(tmp); + is_mdev = (strcmp(subsys, "/sys/bus/mdev") == 0); + free(subsys); + + trace_vfio_mdev(vdev->vbasedev.name, is_mdev); + + if (vdev->vbasedev.balloon_allowed && !is_mdev) { + error_setg(errp, "x-balloon-allowed only potentially compatible " + "with mdev devices"); + vfio_put_group(group); + goto error; + } + ret = vfio_get_device(group, vdev->vbasedev.name, &vdev->vbasedev, errp); if (ret) { vfio_put_group(group); @@ -3170,6 +3192,8 @@ static Property vfio_pci_dev_properties[] = { DEFINE_PROP_BIT("x-igd-opregion", VFIOPCIDevice, features, 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), 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/hw/vfio/trace-events b/hw/vfio/trace-events index d2a74952e389..a85e8662eadb 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -39,6 +39,7 @@ vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot reset: % vfio_populate_device_config(const char *name, unsigned long size, unsigned long offset, unsigned long flags) "Device %s config:\n size: 0x%lx, offset: 0x%lx, flags: 0x%lx" vfio_populate_device_get_irq_info_failure(void) "VFIO_DEVICE_GET_IRQ_INFO failure: %m" vfio_realize(const char *name, int group_id) " (%s) group %d" +vfio_mdev(const char *name, bool is_mdev) " (%s) is_mdev %d" vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset) "%s 0x%x@0x%x" vfio_pci_reset(const char *name) " (%s)" vfio_pci_reset_flr(const char *name) "%s FLR/VFIO_DEVICE_RESET" diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index a9036929b220..15ea6c26fdbc 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -112,6 +112,7 @@ typedef struct VFIODevice { bool reset_works; bool needs_reset; bool no_mmap; + bool balloon_allowed; VFIODeviceOps *ops; unsigned int num_irqs; unsigned int num_regions; @@ -131,6 +132,7 @@ typedef struct VFIOGroup { QLIST_HEAD(, VFIODevice) device_list; QLIST_ENTRY(VFIOGroup) next; QLIST_ENTRY(VFIOGroup) container_next; + bool balloon_allowed; } VFIOGroup; typedef struct VFIODMABuf {