Current vfio-pci implementation disallows to mmap the page containing MSI-X table in case that users can write directly to MSI-X table and generate an incorrect MSIs. However, this will cause some performance issue when there are some critical device registers in the same page as the MSI-X table. We have to handle the mmio access to these registers in QEMU emulation rather than in guest. To solve this issue, this series allows to expose MSI-X table to userspace when hardware enables the capability of interrupt remapping which can ensure that a given PCI device can only shoot the MSIs assigned for it. And we introduce a new bus_flags PCI_BUS_FLAGS_MSI_REMAP to test this capability on PCI side for different archs. The patch 3 are based on the proposed patchset[1]. Changelog v2: - Make the commit log more clear - Replace pci_bus_check_msi_remapping() with pci_bus_msi_isolated() so that we could clearly know what the function does - Set PCI_BUS_FLAGS_MSI_REMAP in pci_create_root_bus() instead of iommu_bus_notifier() - Reserve VFIO_REGION_INFO_FLAG_CAPS when we allow to mmap MSI-X table so that we can know whether we allow to mmap MSI-X table in QEMU [1] https://www.mail-archive.com/linux-kernel%40vger.kernel.org/msg1138820.html Yongji Xie (6): PCI: Add a new PCI_BUS_FLAGS_MSI_REMAP flag PCI: Set PCI_BUS_FLAGS_MSI_REMAP if MSI controller enables IRQ remapping PCI: Set PCI_BUS_FLAGS_MSI_REMAP if IOMMU have capability of IRQ remapping iommu: Set PCI_BUS_FLAGS_MSI_REMAP on iommu driver initialization pci-ioda: Set PCI_BUS_FLAGS_MSI_REMAP for IODA host bridge vfio-pci: Allow to expose MSI-X table to userspace if interrupt remapping is enabled arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++++ drivers/iommu/iommu.c | 8 ++++++++ drivers/pci/msi.c | 15 +++++++++++++++ drivers/pci/probe.c | 7 +++++++ drivers/vfio/pci/vfio_pci.c | 17 ++++++++++++++--- drivers/vfio/pci/vfio_pci_rdwr.c | 3 ++- include/linux/msi.h | 5 ++++- include/linux/pci.h | 1 + 8 files changed, 59 insertions(+), 5 deletions(-) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
