From nobody Sun Dec 14 12:37:16 2025 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=1765552025; cv=none; d=zohomail.com; s=zohoarc; b=iPer85/M7SepO1hYywMVlyiEamLIaE6YNX0yO9m+Jro/Yt7sNqdjD+U0hurQsHpUjapEGpG9TRm39sm1fZuN6771aCtToU52q/XqXYR2BMRSlUGoE778jg3OtiScDEnEnZlnrKF0jXMEJieosxdJlvDKc4poLNx+6XxfJuu6C04= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1765552025; 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=An7ksy++b8pjEaWmUyibgQbRoj3a44CDnsQt2f4omE0=; b=L204qmBuu8t/P3NhbchSoAU+91nS8z+l+jaOc0S9flIztAcf782LyJY1m1IAHLufJujOf//fqpUzgETv8Nqecjz52c7mCz/6X61aP1NtmzFZ8zIPxm++Bh0T6KtzzBKX062We3Shl5FPI0Fnipl+nwclLFizfo1n63tnO+UyZZQ= 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 1765552022384231.31880331209493; Fri, 12 Dec 2025 07:07:02 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vU4i6-0002ii-SZ; Fri, 12 Dec 2025 10:05:34 -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 1vU4i4-0002Wf-6J for qemu-devel@nongnu.org; Fri, 12 Dec 2025 10:05:32 -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 1vU4i1-00065w-5f for qemu-devel@nongnu.org; Fri, 12 Dec 2025 10:05:31 -0500 Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-193-hTCN029VPEGH7dqKmMJ2SQ-1; Fri, 12 Dec 2025 10:05:27 -0500 Received: by mail-pg1-f200.google.com with SMTP id 41be03b00d2f7-c0c65e5f688so519182a12.1 for ; Fri, 12 Dec 2025 07:05:26 -0800 (PST) Received: from rhel9-box.lan ([122.172.173.62]) by smtp.googlemail.com with ESMTPSA id d9443c01a7336-29ee9d38ad1sm57046655ad.29.2025.12.12.07.05.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Dec 2025 07:05:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1765551928; 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=An7ksy++b8pjEaWmUyibgQbRoj3a44CDnsQt2f4omE0=; b=XvIHtSAK2m5X91VogQ0MLSFTUxivRExG2Vz+dTJoC4k3ilOit5Yuum0+24u22yJDrFVBZT r9hmaQDS0c1kGrDyGmwajHHYKZRASjZhkgJ3xpzjvcwcs5BFModrnKO9b+eS2VCJcio4ud gmt+vpolSNm1oBDU/Jsw2SmAK6eafNg= X-MC-Unique: hTCN029VPEGH7dqKmMJ2SQ-1 X-Mimecast-MFC-AGG-ID: hTCN029VPEGH7dqKmMJ2SQ_1765551926 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1765551926; x=1766156726; 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=An7ksy++b8pjEaWmUyibgQbRoj3a44CDnsQt2f4omE0=; b=qTKhQwveBFek5NfYsMjjJA8CVjM38BvPFzeUgugVylqCSAA3xf0btspFgitMqzvBWm j7YMyPbkpibglnnJC2mFGCzPavS74tYkoEI8cNcW4bJu3SW4GZsoU1ISdg1Ejf35Dbv/ 6A20aE5eOuoFUgHmJER0tDC5B8OFS/WRmLzTivMFYJ39oiu+OAKyElzGomlITqJzlvtf 4v36ELkzwO26M8dpPzkVYwXSRiUgwJYAD+iFZLGoo6ffIOvyy+Kgtwovjl5J2zqESEpY VKicT9n22nHTl4n1SaAaHte4Ul4O6GUxubhkoSWXbMk7qahP4RA7ZaTKGUasvSvhuU+A amNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765551926; x=1766156726; 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=An7ksy++b8pjEaWmUyibgQbRoj3a44CDnsQt2f4omE0=; b=u4j1BAhw7xtgCeT5euDcliz2qpM2XEtaSrm6YP1recWcCKuO7uqKdDNbByaNlLgaQP vS1Qr44DDVDM08asfUaJ0Gr2jX32LSy0OZVCrUyEPMGURQF8NeFr0s25Jv3RUJ1G2/g+ yBmxwwYHtZt35EQ6AXX1qFKJkg+Qi+xLbExX+mAM8+YbSw+kMYlYJFgrKp4uSBt6qQSF UiAYS8u5P19XSFX49/cq3nICgtM1+boOrif49H6rFaROdWi9qHF5wVxQlGEQisEDC3Xc /duD1sVQCwRNKfLEavTaJFl0iiNQVmp/y7QXtBl+wMgbii+0YvAxyOAqKk0qt7buanj8 W7uA== X-Forwarded-Encrypted: i=1; AJvYcCVJd2Vtojr+Rf9wPwrGNzLugPAk1lheRq32y3XY+FQLaHWtKDEVqmUgHW9WvuX65mAtTYEb8lAdZRT3@nongnu.org X-Gm-Message-State: AOJu0YxHFZjhUw94sPg2k9bHlSmCOn79FPElGmW0D4TqUfd0npz38Tk3 LsqFLTOF2b/2RXa8chwimQN0eaH74ZXDTvPrrgQtaAUgLhvZ8/XGTaGilwEhsRXEv8tFXq6hqFG qzEzHF7uo2Y+7hEXJmuK02Gu4xIZXLrr9HStBoMOZGH3prS/wGsL5TAeg X-Gm-Gg: AY/fxX4yGK+fd7M0ESw23sc8NiKQRTw77uDD5jyHOS9hi2wt6A+7ustokYVJ09GxgzR PhaijdLcSsn0avdp+/6bI/4H9wOYoutqEnMyoCFCDcs0BijHb5ETBppyWTy3u1LZuNbafRB7Nbd 5FDN76EJzFKiqNnvz44LlVc7jWsHCgutAT05WsA24lTppdtRAqZ2Ralaq/SnR/oeE2dKf2WxNoq B5p1wh/r7e1pALUecsJd4ExS1d0GFG8NvI0qf8YBUdnf+ChsyB/NdUDpHyn6Nn1BjfYtxZ8dfYB IR9GlfBce35HUq/cJ7hgSH3yXZhK7nQdxxkTNRGiP+Wfqxjv3Ayc5BFfrb+WlVSiqdtQk4K2ZIg E4Mr5pcHLdO4DlgrATLXY0zwOHSAx4uTQMv5tveGKSS4= X-Received: by 2002:a17:903:3c6d:b0:298:360:1662 with SMTP id d9443c01a7336-29eee9f1ad5mr54292355ad.1.1765551925751; Fri, 12 Dec 2025 07:05:25 -0800 (PST) X-Google-Smtp-Source: AGHT+IHoKR/S5A//jCh7WGyYiKpZMMZpKIKyrpZfPWPfiXIIh/IS0nvD0Lt12QdEA3Iftgc084U4/Q== X-Received: by 2002:a17:903:3c6d:b0:298:360:1662 with SMTP id d9443c01a7336-29eee9f1ad5mr54291715ad.1.1765551925072; Fri, 12 Dec 2025 07:05:25 -0800 (PST) From: Ani Sinha To: Alex Williamson , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Cc: vkuznets@redhat.com, kraxel@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, Ani Sinha Subject: [PATCH v1 19/28] hw/vfio: generate new file fd for pseudo device and rebind existing descriptors Date: Fri, 12 Dec 2025 20:33:47 +0530 Message-ID: <20251212150359.548787-20-anisinha@redhat.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20251212150359.548787-1-anisinha@redhat.com> References: <20251212150359.548787-1-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: 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: 1765552028099158500 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 | 81 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 78 insertions(+), 3 deletions(-) diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c index 23d13e5db5..ad9e9c9ead 100644 --- a/hw/vfio/helpers.c +++ b/hw/vfio/helpers.c @@ -109,12 +109,66 @@ 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, + }; + + 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) @@ -136,6 +190,7 @@ 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; @@ -152,6 +207,11 @@ 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)) { @@ -159,6 +219,11 @@ 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; } @@ -171,6 +236,7 @@ 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"); @@ -182,6 +248,15 @@ 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