From nobody Tue Feb 10 02:42:37 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1769491142; cv=none; d=zohomail.com; s=zohoarc; b=MkGJLN8GghwgxbEFv/wbThS5e7xsuc18kCN7q0zBuGOhgp3y9bxc2GXBaBe0Qt0CyKwnY8ou9yXcUvgJOdX5xbf8qDHS3K/+vPXZcynGgpLH+Ju7YaGdCWHDNqutikh+4VHwGyxmM3522aMATEJ79ZcgKKQbG0RcZRX2NjyS4bc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1769491142; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=sIxPRkcXYN+jvBabI3Le3pQDAeITVcKP3DhgLvFqdx4=; b=FnGoEP9Z4OEtzZJMVh6HEmTlBntdORnsgaOJhPzljskzONJZRYBXXa6HJ5jcMYN7Jwl5o+PdtP8l35AeR7Df4vBhvgziIH8ScMvpMlej2//kUNSOFD4V2p13AUKKMPzEwUPsmwODsfaS27QhL7vnXleFALO25p2XQ1xKcDyKeRo= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1769491142678552.9196868856939; Mon, 26 Jan 2026 21:19:02 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vkbSi-0007uF-Re; Tue, 27 Jan 2026 00:18:00 -0500 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 1vkbSV-0007Mc-74 for qemu-devel@nongnu.org; Tue, 27 Jan 2026 00:17:48 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vkbST-0000Af-KB for qemu-devel@nongnu.org; Tue, 27 Jan 2026 00:17:46 -0500 Received: from mail-pj1-f70.google.com (mail-pj1-f70.google.com [209.85.216.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-665-1okVMy4CPvCno2vgGjQh1g-1; Tue, 27 Jan 2026 00:17:42 -0500 Received: by mail-pj1-f70.google.com with SMTP id 98e67ed59e1d1-352b6ad49ddso3497115a91.0 for ; Mon, 26 Jan 2026 21:17:42 -0800 (PST) Received: from rhel9-box.lan ([122.163.48.79]) by smtp.googlemail.com with ESMTPSA id 98e67ed59e1d1-353f6230d5dsm1110925a91.17.2026.01.26.21.17.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Jan 2026 21:17:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769491064; 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=sIxPRkcXYN+jvBabI3Le3pQDAeITVcKP3DhgLvFqdx4=; b=H393JED/KYpFrVeZDGd5ug1llcw70M7URa9xcFyEASf4L/8vn3Z0lC2jc7wUBVtQG3yzYO ggDExnmocYjkQBFhdIGb/TPZfp0PNTkC9C2Eax2CFQf20ZEaie3JByXUoOoYLg7hS4eUB1 02o1qFoLt6x/jscssM+CtoeFiw4tnVE= X-MC-Unique: 1okVMy4CPvCno2vgGjQh1g-1 X-Mimecast-MFC-AGG-ID: 1okVMy4CPvCno2vgGjQh1g_1769491061 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1769491061; x=1770095861; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=sIxPRkcXYN+jvBabI3Le3pQDAeITVcKP3DhgLvFqdx4=; b=YtkbWPcIgmROkVSDwHtfsQs6SlVtt0YhHx7VDv1ipv2KT60kdCVcUEZIVlCu8aJtzX AgVOYwAQ4TL49mDd7xUEJCaWwtmhSArXgLgl86+MMH/cvNHCFRl+uJAYc0vDjO3m788o NLwAuPap8PEj9X61RvPWeH0hETaDEEbRNKbU9po2YfkTGuRqX71IDJ25g7bvGreo9W+S pgakUcPUoSAJoEMOOjmfLBIaCLFv4FqmVzDjWWBxi6Wx/FkMuq269Azv79DG2SRa8FHk mGByN7iS+TbSQ5jSX8JnT8zaUmbwMCK/s04iT+t6OERjlhJS2qNb6dHPLpsJEkyrgU7b DnlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769491061; x=1770095861; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=sIxPRkcXYN+jvBabI3Le3pQDAeITVcKP3DhgLvFqdx4=; b=rASxBYfq/RDT0gH2tBlHIO8gWrrVT8Wj5XqC6LlJAhMNFSGxp1FCdkbnvTAMs5uM4n TXlSz0c9OO5GqnGbJgGS5qwQmvsi0QZnDAIZa/2OGJv5eQ7tfi4/sSHLQVwahbWBnVXC xeErRxWSqEzqD4qfs6qSmaZ8RKtpgHhGgNB3QwrozdqoSPl+TT+OPBLrZPWssjQENtYt Fl6fEGSbAaiZYLwzJOJW3Lq3akpnbArwS2RYneFyiXO7o32tDydDIoHtpl4TRJcAmzJh m/NV9LQxHteEP1w41f5/ucBsM7PYl9F/99yYh65XFGzqU6SeUP14qkS+j0PE9OT+Tpq7 hRnQ== X-Forwarded-Encrypted: i=1; AJvYcCVK6w49trDVsHOGvLWsIt3N/5GbLbuTT4xsxE7oPaIFA2mmThodjddm+lzxhcKlPUz24nIC06P1hO2r@nongnu.org X-Gm-Message-State: AOJu0YypgFnz0Ei+AtO/MOvIv6VebiR+vJUCPMh1qvj+PN/tdTD/As9r Zkm0nSEKWx1WsjAGQtuCWlwOk5hbv286WrvYNeoViLkqKpywyMSWZ+GKAVFl+77UTkBDEanko+s vJW6MQDXCbScoj11lSStTYNFSqmKuqoIjjcFInW1Le+eu8uzk5qh06SKH X-Gm-Gg: AZuq6aL1tw+8zywkm+oQdx/qXai1ywdMER/mTCdvsfgYJrvhaSnqZUcrrPuKIs4ct1D E/+InMjh8IxdU7d3ek/cNC3RodcFgz+6jNVud6fUpC16TWnthZNimnzyuwugqPONCKK48GO8ceK NBZDoiPGcRyI/GpLmqP/EUduF0RLTJHDU7tc82on9efygnNr+pyYIOlTH2VgOMjzbZeK26iMAot W8DBlGMn7f+ZORd8agxiESjM3P6TukpH+fKKFmcNL+vlHLI6TzdayfPwoL4U040ateXyS2++SWl b8CyLV2UPX2GO1P5T7BeK42tPUe+Zn5n4YsFSy9QPQcSn24GmOxxLY2SlRiC/Y9jcVaTFFUyI1X NMV314fzz4jFGvRz4ORsLC3lYU8J2k2sI/luFTZsr8w== X-Received: by 2002:a17:90a:d603:b0:341:abdc:8ea2 with SMTP id 98e67ed59e1d1-353feda9712mr707852a91.37.1769491061121; Mon, 26 Jan 2026 21:17:41 -0800 (PST) X-Received: by 2002:a17:90a:d603:b0:341:abdc:8ea2 with SMTP id 98e67ed59e1d1-353feda9712mr707831a91.37.1769491060735; Mon, 26 Jan 2026 21:17:40 -0800 (PST) From: Ani Sinha To: Alex Williamson , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Cc: kraxel@redhat.com, Ani Sinha , qemu-devel@nongnu.org Subject: [PATCH v3 22/33] hw/vfio: generate new file fd for pseudo device and rebind existing descriptors Date: Tue, 27 Jan 2026 10:45:50 +0530 Message-ID: <20260127051612.219475-23-anisinha@redhat.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20260127051612.219475-1-anisinha@redhat.com> References: <20260127051612.219475-1-anisinha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=anisinha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1769491143952158500 Content-Type: text/plain; charset="utf-8" Normally the vfio pseudo device file descriptor lives for the life of the V= M. However, when the kvm VM file descriptor changes, a new file descriptor for the pseudo device needs to be generated against the new kvm VM descript= or. Other existing vfio descriptors needs to be reattached to the new pseudo de= vice descriptor. This change performs the above steps. Signed-off-by: Ani Sinha --- hw/vfio/helpers.c | 86 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 83 insertions(+), 3 deletions(-) diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c index f68f8165d0..d467875b4b 100644 --- a/hw/vfio/helpers.c +++ b/hw/vfio/helpers.c @@ -110,12 +110,71 @@ bool vfio_get_info_dma_avail(struct vfio_iommu_type1_= info *info, #ifdef CONFIG_KVM /* * We have a single VFIO pseudo device per KVM VM. Once created it lives - * for the life of the VM. Closing the file descriptor only drops our - * reference to it and the device's reference to kvm. Therefore once - * initialized, this file descriptor is only released on QEMU exit and + * for the life of the VM except when the vm file descriptor changes for + * confidential virtual machines. In that case, the old file descriptor is + * closed and a new file descriptor is recreated. Closing the file descri= ptor + * only drops our reference to it and the device's reference to kvm. + * Therefore once initialized, this file descriptor is normally only relea= sed + * on QEMU exit (except for confidential VMs as stated above) and * we'll re-use it should another vfio device be attached before then. */ int vfio_kvm_device_fd =3D -1; + +typedef struct KVMVfioFileFd { + int fd; + QLIST_ENTRY(KVMVfioFileFd) node; +} KVMVfioFileFd; + +static QLIST_HEAD(, KVMVfioFileFd) kvm_vfio_file_fds =3D + QLIST_HEAD_INITIALIZER(kvm_vfio_file_fds); + +static int kvm_vfio_filefd_rebind(NotifierWithReturn *notifier, void *data, + Error **errp); +static struct NotifierWithReturn kvm_vfio_vmfd_change_notifier =3D { + .notify =3D kvm_vfio_filefd_rebind, +}; + +static int kvm_vfio_filefd_rebind(NotifierWithReturn *notifier, void *data, + Error **errp) +{ + KVMVfioFileFd *file_fd; + int ret =3D 0; + struct kvm_device_attr attr =3D { + .group =3D KVM_DEV_VFIO_FILE, + .attr =3D KVM_DEV_VFIO_FILE_ADD, + }; + struct kvm_create_device cd =3D { + .type =3D KVM_DEV_TYPE_VFIO, + }; + + /* we are not interested in pre vmfd change notification */ + if (((VmfdChangeNotifier *)data)->pre) { + return 0; + } + + if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) { + error_setg_errno(errp, errno, "Failed to create KVM VFIO device"); + return -errno; + } + + if (vfio_kvm_device_fd) { + close(vfio_kvm_device_fd); + } + + vfio_kvm_device_fd =3D cd.fd; + + QLIST_FOREACH(file_fd, &kvm_vfio_file_fds, node) { + attr.addr =3D (uint64_t)(unsigned long)&file_fd->fd; + if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) { + error_setg_errno(errp, errno, + "Failed to add fd %d to KVM VFIO device", + file_fd->fd); + ret =3D -errno; + } + } + return ret; +} + #endif =20 void vfio_kvm_device_close(void) @@ -137,6 +196,7 @@ int vfio_kvm_device_add_fd(int fd, Error **errp) .attr =3D KVM_DEV_VFIO_FILE_ADD, .addr =3D (uint64_t)(unsigned long)&fd, }; + KVMVfioFileFd *file_fd; =20 if (!kvm_enabled()) { return 0; @@ -153,6 +213,11 @@ int vfio_kvm_device_add_fd(int fd, Error **errp) } =20 vfio_kvm_device_fd =3D cd.fd; + /* + * If the vm file descriptor changes, add a notifier so that we can + * re-create the vfio_kvm_device_fd. + */ + kvm_vmfd_add_change_notifier(&kvm_vfio_vmfd_change_notifier); } =20 if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) { @@ -160,6 +225,11 @@ int vfio_kvm_device_add_fd(int fd, Error **errp) fd); return -errno; } + + file_fd =3D g_malloc0(sizeof(*file_fd)); + file_fd->fd =3D fd; + QLIST_INSERT_HEAD(&kvm_vfio_file_fds, file_fd, node); + #endif return 0; } @@ -172,6 +242,7 @@ int vfio_kvm_device_del_fd(int fd, Error **errp) .attr =3D KVM_DEV_VFIO_FILE_DEL, .addr =3D (uint64_t)(unsigned long)&fd, }; + KVMVfioFileFd *file_fd; =20 if (vfio_kvm_device_fd < 0) { error_setg(errp, "KVM VFIO device isn't created yet"); @@ -183,6 +254,15 @@ int vfio_kvm_device_del_fd(int fd, Error **errp) "Failed to remove fd %d from KVM VFIO device", fd= ); return -errno; } + + QLIST_FOREACH(file_fd, &kvm_vfio_file_fds, node) { + if (file_fd->fd =3D=3D fd) { + QLIST_REMOVE(file_fd, node); + g_free(file_fd); + break; + } + } + #endif return 0; } --=20 2.42.0