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SubjectRe: [PATCH kernel 0/3] vfio-pci: Add support for mmapping MSI-X table
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Ouch, this is a wrong one, please ignore. I'll repost in a sec.


On 15/06/17 15:06, Alexey Kardashevskiy wrote:
> Here is a patchset which Yongji was working on before
> leaving IBM LTC. Since we still want to have this functionality
> in the kernel (DPDK is the first user), here is a rebase
> on the current upstream.
>
>
> 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
> v3:
> - rebased on the current upstream
>
> 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
>
>
> This is based on sha1
> 63f700aab4c1 Linus Torvalds "Merge tag 'xtensa-20170612' of git://github.com/jcmvbkbc/linux-xtensa".
>
> Please comment. Thanks.
>
>
>
> Yongji Xie (3):
> PCI: Add a new PCI_BUS_FLAGS_MSI_REMAP flag
> 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
>
> include/linux/pci.h | 1 +
> arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++++
> drivers/vfio/pci/vfio_pci.c | 18 +++++++++++++++---
> drivers/vfio/pci/vfio_pci_rdwr.c | 3 ++-
> 4 files changed, 26 insertions(+), 4 deletions(-)
>


--
Alexey

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