From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E0AE1D79A3 for ; Mon, 3 Mar 2025 17:33:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741023200; cv=none; b=W/S8AcREM5L2vlMYSbxrvjv4+2LhOBtSzQfrJm3MqCXEnnu/KoRWg2w3y/Z3VqnXg1FdMXZa15whtyQE8LND7lV/XLqOmo7pZAUMZyfZoVmwBymuJ08DSfWYMMajxm5944TpvwVnFjvtHgxoktEJUtG1UnqIK68ueKNfWNgKGag= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741023200; c=relaxed/simple; bh=Kqke1zXRTdE0PHPb+71qhUA9lMSBTCX8sSQVT4I2Ut4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZquX6QibqUyAJILstoOVsZ5V7ebSk/TD0mAy7b690iR92qKaaj+BGpAHr+UaaKgaP3pzkmnfBV7BWO1Y3H9ahpDleiGWoxK7VVTqvb1AbLU+7RRqazAY9gN7v4aRR/SN3JlF4TFocAdwb78Xr8fqMMM3EYXTHTJKwbm+UI91Ppw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=QAGSqzCe; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QAGSqzCe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741023197; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=riX1iNIQhseaZsPbJjiHdH5ZxszgBUyrqDQWObE9EXo=; b=QAGSqzCe1ir92rMZd2fBt+C+zuirk+G/6LRPAP2UvnQ6I8RASUkiomPI/0AzBqj2ZM5n4u Q9SCaF8wrIE046n3cDDkwLIdno16iOHj7i4sJc9Ipr0lXYEEZhd80wBYlLzMx3WxavthHF 7FXi4X9TJgq4Q8rGhW0lp21BaopEIVA= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-45-ERzWVmw4OFqMBETvDi_x5g-1; Mon, 03 Mar 2025 12:33:16 -0500 X-MC-Unique: ERzWVmw4OFqMBETvDi_x5g-1 X-Mimecast-MFC-AGG-ID: ERzWVmw4OFqMBETvDi_x5g_1741023196 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-390f9d00750so1378902f8f.3 for ; Mon, 03 Mar 2025 09:33:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741023195; x=1741627995; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=riX1iNIQhseaZsPbJjiHdH5ZxszgBUyrqDQWObE9EXo=; b=hOb5FNjWWhkh7OoAuAWenhSULNS1FL9JTAL8rlBtNnFhc/tBHLKwSL/Cwfxrjtejl1 nuAlliVX8lcvVBRzWbSVoYw1rA+qWyAQXur2zR5lwc/XK5gfyDCW6248W+fvjC/uRb/C SWYPw2SkvO9XsPAYDh/A7kRGC3hTmTZyiHgOb6PSktQHDExuge0qiUWDpaSknoXJ2pE6 DldZFKHK1+v96hMlPX6OIFL8IsfUFmQYN0+M2ktHwc92gAM9paZJT8WF9OZbZ1lA8aI/ 3PBn+vmgn9ehTanAMYbuB9KBndwaoz2Yw1wyprXxWNWwC/CTVaVJM3b5LBOjs7Egs+g7 xzWw== X-Forwarded-Encrypted: i=1; AJvYcCWGwzRbsQ4isAReuOkZXVrs0vOfqbSRxnSoOrW9tpMuw3bvUcENbalZF4N5Mb5NfUMaIJXIRXTkKzPLGJQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yw6y9oKBtSktous9iqcu0yYcQgTYSkka4/L0s0280K01d5shCmj Kk3ffPxVgioXDEOs6uv4A3oHI6L6aKwK+7fhv374lE3Y5ehnIjOjLJwz3hX7zbnRWamhpLLgQh4 Xkr2ppx5WTnoP5il3kgxnlHv9u7T/l795I2MkeC7zd45UyZLXqyF0Fs1anbdHiFMs4pHxXg== X-Gm-Gg: ASbGncuqAOLxR/vPUdiCDTQu1dTrnJZe8avSDZkQmwuBx4O7Sd8d+Qcb0ky08HgLLUC WkF2oJhmNr4quS0kZU1GuoPIdliGbJWIxsinSmviqLItO6mjRfKpakKUH6QFyeOz+Kb8iT6/X9u 0inYM8yFTRcYAbnQuLgmoH8O3gD9E8HxyFGbayHc6eqBwfLjWopl7pWPo0m80xTuOAA4lVQIbe1 sE3HGPwoJWHpA7edsRhXsXnNGwQdfQWJsJjKQIrx28zLZhNe4xbhqJFys0n+SipzR1R4cMslkXm zrv9dckJOQ== X-Received: by 2002:a5d:6da3:0:b0:390:e9ea:59a with SMTP id ffacd0b85a97d-390ec7c8eb6mr11963054f8f.5.1741023195330; Mon, 03 Mar 2025 09:33:15 -0800 (PST) X-Google-Smtp-Source: AGHT+IG0GmDlZsbzQlj1pj5FfLVE18PQfmrSwJDhwqCdM5eQRgnv/LJj6Wq+AmT8QxKX5JIr/1sNZA== X-Received: by 2002:a5d:6da3:0:b0:390:e9ea:59a with SMTP id ffacd0b85a97d-390ec7c8eb6mr11963001f8f.5.1741023194570; Mon, 03 Mar 2025 09:33:14 -0800 (PST) Received: from redhat.com ([2a0d:6fc0:1514:ea00:6409:9e94:fe6f:3eb6]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-390e485db6csm15218056f8f.91.2025.03.03.09.33.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Mar 2025 09:33:14 -0800 (PST) Date: Mon, 3 Mar 2025 12:33:10 -0500 From: "Michael S. Tsirkin" To: Jason Wang Cc: Cindy Lu , michael.christie@oracle.com, sgarzare@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: Re: [PATCH v7 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER Message-ID: <20250303122619-mutt-send-email-mst@kernel.org> References: <20250302143259.1221569-1-lulu@redhat.com> <20250302143259.1221569-9-lulu@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Mar 03, 2025 at 01:52:06PM +0800, Jason Wang wrote: > On Sun, Mar 2, 2025 at 10:34 PM Cindy Lu wrote: > > > > Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`, > > to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl. > > When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl > > is disabled, and any attempt to use it will result in failure. > > > > Signed-off-by: Cindy Lu > > --- > > drivers/vhost/Kconfig | 15 +++++++++++++++ > > drivers/vhost/vhost.c | 11 +++++++++++ > > 2 files changed, 26 insertions(+) > > > > diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig > > index b455d9ab6f3d..e5b9dcbf31b6 100644 > > --- a/drivers/vhost/Kconfig > > +++ b/drivers/vhost/Kconfig > > @@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY > > If unsure, say "N". > > > > endif > > + > > +config VHOST_ENABLE_FORK_OWNER_IOCTL > > + bool "Enable IOCTL VHOST_FORK_FROM_OWNER" > > + default n > > + help > > + This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows > > + userspace applications to modify the thread mode for vhost devices. > > + > > + By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`, > > + meaning the ioctl is disabled and any operation using this ioctl > > + will fail. > > + When the configuration is enabled (y), the ioctl becomes > > + available, allowing users to set the mode if needed. > > + > > + If unsure, say "N". > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > index fb0c7fb43f78..09e5e44dc516 100644 > > --- a/drivers/vhost/vhost.c > > +++ b/drivers/vhost/vhost.c > > @@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) > > r = vhost_dev_set_owner(d); > > goto done; > > } > > + > > +#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL > > if (ioctl == VHOST_FORK_FROM_OWNER) { > > u8 inherit_owner; > > /*inherit_owner can only be modified before owner is set*/ > > @@ -2313,6 +2315,15 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) > > r = 0; > > goto done; > > } > > + > > +#else > > + if (ioctl == VHOST_FORK_FROM_OWNER) { > > + /* When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is 'n', return error */ > > + r = -ENOTTY; > > + goto done; > > + } why do we need this? won't it fail as any other unsupported ioctl? > > +#endif > > + > > /* You must be the owner to do anything else */ > > r = vhost_dev_check_owner(d); > > if (r) > > -- > > 2.45.0 > > Do we need to change the default value of the inhert_owner? For example: > > #ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL > inherit_owner = false; > #else > inherit_onwer = true; > #endif > > ? I feel it is best to keep the default consistent. All the kconfig should do, is block the ioctl. > Other patches look good to me. > > Thanks > > >