Re: [RFC PATCH v5 0/5] vfio-pci: Add support for mmapping MSI-X table

Alexey Kardashevskiy
2017-09-11T03:27:59Z

On 29/08/17 12:58, Alexey Kardashevskiy wrote:
> On 21/08/17 12:47, Alexey Kardashevskiy wrote:
>> Folks,
>>
>> Ok, people did talk, exchanged ideas, lovely :) What happens now? Do I
>> repost this or go back to PCI bus flags or something else? Thanks.
>
>
> Anyone, any help? How do we proceed with this? Thanks.

Ping, anyone?

Or everybody is just waiting for the kvm forum to discuss it in person? Thanks.

>
>
>
>>
>>
>>
>> On 14/08/17 19:45, Alexey Kardashevskiy wrote:
>>> Folks,
>>>
>>> Is there anything to change besides those compiler errors and David's
>>> comment in 5/5? Or the while patchset is too bad? Thanks.
>>>
>>>
>>>
>>> On 07/08/17 17:25, Alexey Kardashevskiy wrote:
>>>> This is a followup for "[PATCH kernel v4 0/6] vfio-pci: Add support for mmapping MSI-X table"
>>>> http://www.spinics.net/lists/kvm/msg152232.html
>>>>
>>>> This time it is using "caps" in IOMMU groups. The main question is if PCI
>>>> bus flags or IOMMU domains are still better (and which one).
>>>
>>>>
>>>>
>>>>
>>>> Here is some background:
>>>>
>>>> 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.
>>>>
>>>>
>>>> This is based on sha1
>>>> 26c5cebfdb6c "Merge branch 'parisc-4.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux"
>>>>
>>>> Please comment. Thanks.
>>>>
>>>> Changelog:
>>>>
>>>> v5:
>>>> * redid the whole thing via so-called IOMMU group capabilities
>>>>
>>>> v4:
>>>> * rebased on recent upstream
>>>> * got all 6 patches from v2 (v3 was missing some)
>>>>
>>>>
>>>>
>>>>
>>>> Alexey Kardashevskiy (5):
>>>> iommu: Add capabilities to a group
>>>> iommu: Set IOMMU_GROUP_CAP_ISOLATE_MSIX if MSI controller enables IRQ
>>>> remapping
>>>> iommu/intel/amd: Set IOMMU_GROUP_CAP_ISOLATE_MSIX if IRQ remapping is
>>>> enabled
>>>> powerpc/iommu: Set IOMMU_GROUP_CAP_ISOLATE_MSIX
>>>> vfio-pci: Allow to expose MSI-X table to userspace when safe
>>>>
>>>> include/linux/iommu.h | 20 ++++++++++++++++++++
>>>> include/linux/vfio.h | 1 +
>>>> arch/powerpc/kernel/iommu.c | 1 +
>>>> drivers/iommu/amd_iommu.c | 3 +++
>>>> drivers/iommu/intel-iommu.c | 3 +++
>>>> drivers/iommu/iommu.c | 35 +++++++++++++++++++++++++++++++++++
>>>> drivers/vfio/pci/vfio_pci.c | 20 +++++++++++++++++---
>>>> drivers/vfio/pci/vfio_pci_rdwr.c | 5 ++++-
>>>> drivers/vfio/vfio.c | 15 +++++++++++++++
>>>> 9 files changed, 99 insertions(+), 4 deletions(-)
>>>>
>>>
>>>
>>
>>
>
>

--
Alexey