From: "Wang, Haiyue" <haiyue.wang@intel.com> To: David Marchand <david.marchand@redhat.com> Cc: dev <dev@dpdk.org>, "Burakov, Anatoly" <anatoly.burakov@intel.com>, "dpdk stable" <stable@dpdk.org>, Maxime Coquelin <maxime.coquelin@redhat.com> Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v3] bus/pci: fix VF bus error for memory access Date: Thu, 25 Jun 2020 04:01:18 +0000 Message-ID: <BN8PR11MB379536639A5174C6420F2843F7920@BN8PR11MB3795.namprd11.prod.outlook.com> (raw) In-Reply-To: <CAJFAV8y6PuUQ3qi0N+xgkfYUcSR4FEpAg66OZM_G2Y1+9qB5RA@mail.gmail.com> > -----Original Message----- > From: David Marchand <david.marchand@redhat.com> > Sent: Thursday, June 25, 2020 04:01 > To: Wang, Haiyue <haiyue.wang@intel.com> > Cc: dev <dev@dpdk.org>; Burakov, Anatoly <anatoly.burakov@intel.com>; dpdk stable <stable@dpdk.org>; > Maxime Coquelin <maxime.coquelin@redhat.com> > Subject: Re: [dpdk-dev] [PATCH v3] bus/pci: fix VF bus error for memory access > > On Mon, Jun 22, 2020 at 1:23 PM Haiyue Wang <haiyue.wang@intel.com> wrote: > > > > To fix CVE-2020-12888, the linux vfio-pci module will invalidate mmaps > > and block MMIO access on disabled memory, it will send a SIGBUS to the > > application: > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=abafbc551fddede3e0a08dee > 1dcde08fc0eb8476 > > > > When the application opens the vfio PCI device, the vfio-pci module will > > enable the bus memory space through PCI read/write access. According to > > the PCIe specification, the 'Memory Space Enable' is always zero for VF: > > > > Table 9-13 Command Register Changes > > > > Bit Location | PF and VF Register Differences | PF | VF > > | From Base | Attributes | Attributes > > -------------+--------------------------------+------------+----------- > > | Memory Space Enable - Does not | | > > | apply to VFs. Must be hardwired| Base | 0b > > 1 | to 0b for VFs. VF Memory Space | | > > | is controlled by the VF MSE bit| | > > | in the VF Control register. | | > > -------------+--------------------------------+------------+----------- > > > > Afterwards the vfio-pci will initialize its own virtual PCI config space > > data ('vconfig') by reading the VF's physical PCI config space, then the > > 'Memory Space Enable' bit in vconfig will always be 0b value. This will > > make the vfio-pci treat the BAR memory space as disabled, and the SIGBUS > > will be triggerred if access these BARs. > > triggered > Fixed in v4. > > > > By investigation, the VF PCI device *passthrough* into the Guest OS by > > QEMU has the 'Memory Space Enable' with 1b value. That's because every > > PCI driver will start to enable the memory space, and this action will > > be hooked by vfio-pci virtual PCI read/write to set the 'Memory Space > > Enable' in vconfig space to 1b. So VF runs in guest OS has 'Mem+', but > > VF runs in host OS has 'Mem-'. > > > > Align with PCI working mode in Guest/QEMU/Host, in DPDK, enable the PCI > > bus memory space explicitly to avoid access on disabled memory. > > > > Fixes: 33604c31354a ("vfio: refactor PCI BAR mapping") > > Cc: stable@dpdk.org > > > > Signed-off-by: Haiyue Wang <haiyue.wang@intel.com> > > Ouch, we just hit it. > Thanks for fixing! > > Tested-by: David Marchand <david.marchand@redhat.com> > > > -- > David Marchand
next prev parent reply other threads:[~2020-06-25 4:01 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-21 17:40 [dpdk-stable] [PATCH v1] " Haiyue Wang 2020-06-22 6:30 ` [dpdk-stable] [PATCH v2] " Haiyue Wang 2020-06-22 8:52 ` Burakov, Anatoly 2020-06-22 11:25 ` Wang, Haiyue 2020-06-22 11:13 ` [dpdk-stable] [PATCH v3] " Haiyue Wang 2020-06-22 12:11 ` Burakov, Anatoly 2020-06-23 15:12 ` [dpdk-stable] [dpdk-dev] " Harman Kalra 2020-06-24 20:01 ` David Marchand 2020-06-25 4:01 ` Wang, Haiyue [this message] 2020-06-25 3:50 ` [dpdk-stable] [PATCH v4] " Haiyue Wang 2020-06-25 14:09 ` David Marchand 2020-06-25 16:45 ` Kevin Traynor 2020-06-25 18:33 ` Wang, Haiyue 2020-06-26 9:10 ` Kevin Traynor 2020-06-26 9:17 ` David Marchand 2020-06-26 14:14 ` Wang, Haiyue
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