54f3fb127d
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=abafbc551fdd 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 triggered 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> Acked-by: Anatoly Burakov <anatoly.burakov@intel.com> Tested-by: Harman Kalra <hkalra@marvell.com> Tested-by: David Marchand <david.marchand@redhat.com> Tested-by: Thierry Martin <thierry.martin.public@gmail.com>
DPDK is a set of libraries and drivers for fast packet processing. It supports many processor architectures and both FreeBSD and Linux. The DPDK uses the Open Source BSD-3-Clause license for the core libraries and drivers. The kernel components are GPL-2.0 licensed. Please check the doc directory for release notes, API documentation, and sample application information. For questions and usage discussions, subscribe to: users@dpdk.org Report bugs and issues to the development mailing list: dev@dpdk.org