From: Harman Kalra <hkalra@marvell.com> To: Haiyue Wang <haiyue.wang@intel.com> Cc: <dev@dpdk.org>, <anatoly.burakov@intel.com>, <stable@dpdk.org> Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v3] bus/pci: fix VF bus error for memory access Date: Tue, 23 Jun 2020 20:42:23 +0530 Message-ID: <20200623151222.GA23588@outlook.office365.com> (raw) In-Reply-To: <20200622111351.101006-1-haiyue.wang@intel.com> On Mon, Jun 22, 2020 at 07:13:51PM +0800, Haiyue Wang 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://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_torvalds_linux.git_commit_-3Fid-3Dabafbc551fddede3e0a08dee1dcde08fc0eb8476&d=DwIDAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=5ESHPj7V-7JdkxT_Z_SU6RrS37ys4UXudBQ_rrS5LRo&m=L4wvNYSLDBSsweJGHfGSw3cDNDi0ioJdsQbH2-pEVqE&s=9v3r9tYw6p5Paet2O3Nc2IPdOL1-o77RjYJx5H8G0vc&e= > > 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. > > 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> Tested-by: Harman Kalra <hkalra@marvell.com> > --- > v3: update the commit log, and fix one debug log with redundant > description. > v2: Rewrite the commit log, and put the link into it even it is long. > --- > drivers/bus/pci/linux/pci_vfio.c | 37 ++++++++++++++++++++++++++++++++ > 1 file changed, 37 insertions(+) > > diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c > index 64cd84a68..ba60e7ce9 100644 > --- a/drivers/bus/pci/linux/pci_vfio.c > +++ b/drivers/bus/pci/linux/pci_vfio.c > @@ -149,6 +149,38 @@ pci_vfio_get_msix_bar(int fd, struct pci_msix_table *msix_table) > return 0; > } > > +/* enable PCI bus memory space */ > +static int > +pci_vfio_enable_bus_memory(int dev_fd) > +{ > + uint16_t cmd; > + int ret; > + > + ret = pread64(dev_fd, &cmd, sizeof(cmd), > + VFIO_GET_REGION_ADDR(VFIO_PCI_CONFIG_REGION_INDEX) + > + PCI_COMMAND); > + > + if (ret != sizeof(cmd)) { > + RTE_LOG(ERR, EAL, "Cannot read command from PCI config space!\n"); > + return -1; > + } > + > + if (cmd & PCI_COMMAND_MEMORY) > + return 0; > + > + cmd |= PCI_COMMAND_MEMORY; > + ret = pwrite64(dev_fd, &cmd, sizeof(cmd), > + VFIO_GET_REGION_ADDR(VFIO_PCI_CONFIG_REGION_INDEX) + > + PCI_COMMAND); > + > + if (ret != sizeof(cmd)) { > + RTE_LOG(ERR, EAL, "Cannot write command to PCI config space!\n"); > + return -1; > + } > + > + return 0; > +} > + > /* set PCI bus mastering */ > static int > pci_vfio_set_bus_master(int dev_fd, bool op) > @@ -427,6 +459,11 @@ pci_rte_vfio_setup_device(struct rte_pci_device *dev, int vfio_dev_fd) > return -1; > } > > + if (pci_vfio_enable_bus_memory(vfio_dev_fd)) { > + RTE_LOG(ERR, EAL, "Cannot enable bus memory!\n"); > + return -1; > + } > + > /* set bus mastering for the device */ > if (pci_vfio_set_bus_master(vfio_dev_fd, true)) { > RTE_LOG(ERR, EAL, "Cannot set up bus mastering!\n"); > -- > 2.27.0 >
next prev parent reply other threads:[~2020-06-23 15:12 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 ` Harman Kalra [this message] 2020-06-24 20:01 ` [dpdk-stable] [dpdk-dev] " David Marchand 2020-06-25 4:01 ` Wang, Haiyue 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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