netdev - Re: [PATCH V1 mlx5-next 11/13] vfio/mlx5: Implement vfio

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20211019112420.GR2744544@nvidia.com>
Date:   Tue, 19 Oct 2021 08:24:20 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
Cc:     Yishai Hadas <yishaih@...dia.com>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "saeedm@...dia.com" <saeedm@...dia.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "leonro@...dia.com" <leonro@...dia.com>,
        "kwankhede@...dia.com" <kwankhede@...dia.com>,
        "mgurtovoy@...dia.com" <mgurtovoy@...dia.com>,
        "maorg@...dia.com" <maorg@...dia.com>
Subject: Re: [PATCH V1 mlx5-next 11/13] vfio/mlx5: Implement vfio_pci driver
 for mlx5 devices

On Tue, Oct 19, 2021 at 09:59:03AM +0000, Shameerali Kolothum Thodi wrote:

> > +	/* Saving switches on */
> > +	if ((old_state & VFIO_DEVICE_STATE_SAVING) !=
> > +	    (state & VFIO_DEVICE_STATE_SAVING) &&
> > +	    (state & VFIO_DEVICE_STATE_SAVING)) {
> > +		if (!(state & VFIO_DEVICE_STATE_RUNNING)) {
> > +			/* serialize post copy */
> > +			ret = mlx5vf_pci_save_device_data(mvdev);
> 
> Does it actually get into post-copy here? The pre-copy state(old_state) 
> has the _SAVING bit set already and post-copy state( new state) also
> has _SAVING set. It looks like we need to handle the post copy in the above
> "Running switches off" and check for (state & _SAVING). 

Right, if statements cannot be nested like this. Probably like this:

if ((new_state ^ old_state) & (VFIO_DEVICE_STATE_SAVING|VFIO_DEVICE_STATE_RUNNING) !=
    (new_state & (VFIO_DEVICE_STATE_SAVING|VFIO_DEVICE_STATE_RUNNING)) == (VFIO_DEVICE_STATE_SAVING)

Jason