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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 917A2D59D99 for ; Mon, 15 Dec 2025 02:32:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vUyND-0006Yd-Kd; Sun, 14 Dec 2025 21:31:43 -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 1vUyNC-0006YK-3Q for qemu-devel@nongnu.org; Sun, 14 Dec 2025 21:31:42 -0500 Received: from mgamail.intel.com ([198.175.65.15]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vUyN8-0008Ty-R7 for qemu-devel@nongnu.org; Sun, 14 Dec 2025 21:31:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1765765899; x=1797301899; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=tiX7N2vhKUAvfBjlXET/egUebwdZROMwT7og7cm0Lsw=; b=huEynkys1pkxUs7gq3OJiNEKJQXuJlJ6ImQw0yuKd4GOS4z3lqJLhgsp 0lau/3EStI6nYfc3wGWwC++90b0UVEsNmAOwoUYHi3ERC+0OE9CX2RnSd ZauXK+m4+/O4xpK7ooI7PnBgnls8whPD8DD2fWler2e3aIkObhvd5ou/D j4gVLa/MmCQ/hfB5dSbowCCM7E35vGJIk5kNASXQtfkR1FjbTkDuJJka2 J3ddKU9m9wEyRzIHt31EGsPTQ/Z9/T0QYvJl8RsmMmdqm11TzidRDD5b1 TuFlLf/FJv7qIvyJy0AKHTJ5KuPhCDmMvlF4SeZKSSxM4UDlcahWt9cna w==; X-CSE-ConnectionGUID: zmxVQvO+T6St1jVCeFvXiA== X-CSE-MsgGUID: Vh4Uxy67TtGvi9G2t6tSvA== X-IronPort-AV: E=McAfee;i="6800,10657,11642"; a="71292782" X-IronPort-AV: E=Sophos;i="6.21,148,1763452800"; d="scan'208";a="71292782" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Dec 2025 18:31:35 -0800 X-CSE-ConnectionGUID: Sm17ex42SJSTORw/p+uZag== X-CSE-MsgGUID: mlws72ftRHqL+lUooLyEIg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,148,1763452800"; d="scan'208";a="197888829" Received: from unknown (HELO [10.238.0.255]) ([10.238.0.255]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Dec 2025 18:31:33 -0800 Message-ID: Date: Mon, 15 Dec 2025 10:31:30 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/9] kvm: Detect guest-memfd flags supported To: Peter Xu Cc: qemu-devel@nongnu.org, Paolo Bonzini , David Hildenbrand , Alexey Kardashevskiy , Chenyi Qiang , Juraj Marcin , Fabiano Rosas References: <20251119172913.577392-1-peterx@redhat.com> <20251119172913.577392-3-peterx@redhat.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=198.175.65.15; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 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, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 12/13/2025 1:23 AM, Peter Xu wrote: > On Fri, Dec 12, 2025 at 11:10:23AM +0800, Xiaoyao Li wrote: >> On 11/20/2025 1:29 AM, Peter Xu wrote: >>> Detect supported guest-memfd flags by the current kernel, and reject >>> creations of guest-memfd using invalid flags. When the cap isn't >>> available, then no flag is supported. >>> >>> Signed-off-by: Peter Xu >>> --- >>> accel/kvm/kvm-all.c | 11 +++++++++++ >>> 1 file changed, 11 insertions(+) >>> >>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c >>> index 96c194ce54..f477014126 100644 >>> --- a/accel/kvm/kvm-all.c >>> +++ b/accel/kvm/kvm-all.c >>> @@ -108,6 +108,7 @@ static int kvm_sstep_flags; >>> static bool kvm_immediate_exit; >>> static uint64_t kvm_supported_memory_attributes; >>> static bool kvm_guest_memfd_supported; >>> +static uint64_t kvm_guest_memfd_flags_supported; >>> static hwaddr kvm_max_slot_size = ~0; >>> static const KVMCapabilityInfo kvm_required_capabilites[] = { >>> @@ -2787,6 +2788,10 @@ static int kvm_init(AccelState *as, MachineState *ms) >>> kvm_guest_memfd_supported = >>> kvm_vm_check_extension(s, KVM_CAP_GUEST_MEMFD) && >>> kvm_vm_check_extension(s, KVM_CAP_USER_MEMORY2); >>> + >>> + ret = kvm_vm_check_extension(s, KVM_CAP_GUEST_MEMFD_FLAGS); >>> + kvm_guest_memfd_flags_supported = ret > 0 ? ret : 0; >>> + >>> kvm_pre_fault_memory_supported = kvm_vm_check_extension(s, KVM_CAP_PRE_FAULT_MEMORY); >>> if (s->kernel_irqchip_split == ON_OFF_AUTO_AUTO) { >>> @@ -4492,6 +4497,12 @@ int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp) >>> return -1; >>> } >>> + if (flags & ~kvm_guest_memfd_flags_supported) { >>> + error_setg(errp, "KVM does not support guest-memfd flag: 0x%"PRIx64, >> >> I'm thinking if need to add "for current VM" like: >> >> KVM does not support guest-memfd flag: xxx for current VM >> >> because kvm_guest_memfd_flags_supported is got from VM-scope CAP and varies >> for different VM types. > > Sure I can amend it. Though I plan to change the sentence slightly: > > if (flags & ~kvm_guest_memfd_flags_supported) { > - error_setg(errp, "KVM does not support guest-memfd flag: 0x%"PRIx64, > + error_setg(errp, "Current KVM instance does not support " > + "guest-memfd flag: 0x%"PRIx64, > flags & ~kvm_guest_memfd_flags_supported); > return -1; > } Works for me. > Thanks, > >> >>> + flags & ~kvm_guest_memfd_flags_supported); >>> + return -1; >>> + } >>> + >>> fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_GUEST_MEMFD, &guest_memfd); >>> if (fd < 0) { >>> error_setg_errno(errp, errno, "Error creating KVM guest_memfd"); >> >