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From: "Li, Miao" <miao.li@intel.com>
To: David Marchand <david.marchand@redhat.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"stable@dpdk.org" <stable@dpdk.org>,
	Maxime Coquelin <maxime.coquelin@redhat.com>,
	"Xia, Chenbo" <chenbo.xia@intel.com>
Subject: RE: [PATCH v2 1/2] net/virtio: fix legacy device IO port map in secondary process
Date: Mon, 3 Jul 2023 08:54:09 +0000	[thread overview]
Message-ID: <CO1PR11MB4900468C4C5910ACB3C23034EE29A@CO1PR11MB4900.namprd11.prod.outlook.com> (raw)
In-Reply-To: <CAJFAV8wiDoZMY8Msfa9=YVpc+9qqVrw-9x3+pm76ArGu=_okOA@mail.gmail.com>

Hi,

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Monday, July 3, 2023 3:48 PM
> To: Li, Miao <miao.li@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org; Maxime Coquelin
> <maxime.coquelin@redhat.com>; Xia, Chenbo <chenbo.xia@intel.com>
> Subject: Re: [PATCH v2 1/2] net/virtio: fix legacy device IO port map in
> secondary process
> 
> On Thu, Jun 29, 2023 at 4:27 AM Miao Li <miao.li@intel.com> wrote:
> >
> > When doing IO port map for legacy device in secondary process,
> > vfio_cfg setup for legacy device like vfio_group_fd and vfio_dev_fd is
> > missing. So, in secondary process, rte_pci_map_device is added for
> > legacy device to setup vfio_cfg and fill in region info like in
> > primary process.
> 
> I think, in legacy mode, there is no PCI mappable memory.
> So there should be no need for this call to rte_pci_map_device.
> 
> What is missing is a vfio setup, is this correct?
> I'd rather see this issue be fixed in the pci_vfio_ioport_map() function.
> 
If adding vfio setup in the pci_vfio_ioport_map() function, vfio will be setup twice in primary process because rte_pci_map_device will be called for legacy device in primary process.
I add IO port region check to skip region map in the next patch.
> 
> >> Fixes: 512e27eeb743 ("net/virtio: move PCI specific dev init to PCI
> >> ethdev init")
> 
> This commit only moved code, and at this point, there was no need for a call to
> rte_pci_map_device in the secondary process case.
> It seems unlikely this is a faulty change.
> 
> The recent addition on the vfio side seems a better culprit, but I am fine with
> being proven wrong :-).
> 
Yes,  the fix commit is wrong, but not the recent addition commit on the vfio side. Because the root cause is missing a vfio setup. After adding recent addition commit, the uninitialized vfio_cfg info(like vfio_dev_fd, region info) will be used so this bug will be found. I think the correct fix commit will be 6d890f8ab512("net/virtio: fix multiple process support").
> 
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Miao Li <miao.li@intel.com>
> 
> 
> --
> David Marchand

Thanks,
Miao Li


  reply	other threads:[~2023-07-03  8:54 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-28  6:36 [PATCH " Miao Li
2023-06-28  6:36 ` [PATCH 2/2] bus/pci: add IO port region check before region map Miao Li
2023-06-29  2:26 ` [PATCH v2 1/2] net/virtio: fix legacy device IO port map in secondary process Miao Li
2023-06-29  2:26   ` [PATCH v2 2/2] bus/pci: add IO port region check before region map Miao Li
2023-07-03  1:19   ` [PATCH v2 1/2] net/virtio: fix legacy device IO port map in secondary process Ling, WeiX
2023-07-03  7:47   ` David Marchand
2023-07-03  8:54     ` Li, Miao [this message]
2023-07-03  8:57       ` David Marchand
2023-07-03  9:31         ` Xia, Chenbo
2023-07-07 17:03           ` Gupta, Nipun
2023-07-06  8:58     ` Xia, Chenbo

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