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Groups > linux.kernel > #1359752
| From | Yongji Xie <xyjxie@linux.vnet.ibm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH v4 6/7] vfio-pci: Allow to mmap MSI-X table if IOMMU_CAP_INTR_REMAP was set |
| Date | 2016-03-17 12:40 +0100 |
| Message-ID | <rdErv-6Pk-1@gated-at.bofh.it> (permalink) |
| References | <r9Y5r-8lu-9@gated-at.bofh.it> <r9Yf7-8p8-1@gated-at.bofh.it> <rdmEj-2Zu-33@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 2016/3/17 0:31, Alex Williamson wrote:
> [cc+ Eric, Will]
>
> On Mon, 7 Mar 2016 15:48:37 +0800
> Yongji Xie <xyjxie@linux.vnet.ibm.com> wrote:
>
>> Current vfio-pci implementation disallows to mmap MSI-X
>> table in case that user get to touch this directly.
>>
>> But we should allow to mmap these MSI-X tables if IOMMU
>> supports interrupt remapping which can ensure that a
>> given pci device can only shoot the MSIs assigned for it.
>>
>> Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
>> ---
>> drivers/vfio/pci/vfio_pci.c | 8 +++++---
>> drivers/vfio/pci/vfio_pci_rdwr.c | 4 +++-
>> 2 files changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
>> index 49d7a69..d6f4788 100644
>> --- a/drivers/vfio/pci/vfio_pci.c
>> +++ b/drivers/vfio/pci/vfio_pci.c
>> @@ -592,13 +592,14 @@ static long vfio_pci_ioctl(void *device_data,
>> IORESOURCE_MEM && !pci_resources_share_page(pdev,
>> info.index)) {
>> info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
>> - if (info.index == vdev->msix_bar) {
>> + if (!iommu_capable(pdev->dev.bus,
>> + IOMMU_CAP_INTR_REMAP) &&
>> + info.index == vdev->msix_bar) {
> We only need to test the IOMMU capability if it's the msix BAR, so why
> test these in the reverse order? It should be:
>
> info.index == vdev->msix_bar &&
> !iommu_capable(pdev->dev.bus,
> IOMMU_CAP_INTR_REMAP)
>
> Same below.
OK. I'll fix it.
> I think we also have the problem that ARM SMMU is setting this
> capability when it's really not doing anything at all to provide
> interrupt isolation. Adding Eric and Will to the Cc for comment.
>
> I slightly dislike using an IOMMU API interface here to determine if
> it's safe to allow user access to the MSIx vector table, but it seems
> like the best option we have at this point, if it's actually true for
> all the IOMMU drivers participating in the IOMMU API.
>
>> ret = msix_sparse_mmap_cap(vdev, &caps);
>> if (ret)
>> return ret;
>> }
>> }
>> -
>> break;
>> case VFIO_PCI_ROM_REGION_INDEX:
>> {
>> @@ -1029,7 +1030,8 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
>> if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
>> return -EINVAL;
>>
>> - if (index == vdev->msix_bar) {
>> + if (!iommu_capable(pdev->dev.bus, IOMMU_CAP_INTR_REMAP) &&
>> + index == vdev->msix_bar) {
>> /*
>> * Disallow mmaps overlapping the MSI-X table; users don't
>> * get to touch this directly. We could find somewhere
>> diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
>> index 5ffd1d9..1c46c29 100644
>> --- a/drivers/vfio/pci/vfio_pci_rdwr.c
>> +++ b/drivers/vfio/pci/vfio_pci_rdwr.c
>> @@ -18,6 +18,7 @@
>> #include <linux/uaccess.h>
>> #include <linux/io.h>
>> #include <linux/vgaarb.h>
>> +#include <linux/iommu.h>
>>
>> #include "vfio_pci_private.h"
>>
>> @@ -164,7 +165,8 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
>> } else
>> io = vdev->barmap[bar];
>>
>> - if (bar == vdev->msix_bar) {
>> + if (!iommu_capable(pdev->dev.bus, IOMMU_CAP_INTR_REMAP) &&
>> + bar == vdev->msix_bar) {
> Do we really want to test this on *every* read/write to any BAR (order
> of tests matter)? Even in the case of the MSIx BAR, should we cache
> this when the device is first opened?
I will cache this in vfio_pci_open().
Thanks,
Yongji Xie
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[RFC PATCH v4 0/7] vfio-pci: Allow to mmap sub-page MMIO BARs and MSI-X table Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-07 08:50 +0100
[RFC PATCH v4 6/7] vfio-pci: Allow to mmap MSI-X table if IOMMU_CAP_INTR_REMAP was set Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-07 09:00 +0100
Re: [RFC PATCH v4 6/7] vfio-pci: Allow to mmap MSI-X table if IOMMU_CAP_INTR_REMAP was set Alex Williamson <alex.williamson@redhat.com> - 2016-03-16 17:40 +0100
Re: [RFC PATCH v4 6/7] vfio-pci: Allow to mmap MSI-X table if IOMMU_CAP_INTR_REMAP was set Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-17 12:40 +0100
[RFC PATCH v4 5/7] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-07 09:00 +0100
Re: [RFC PATCH v4 5/7] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive Alex Williamson <alex.williamson@redhat.com> - 2016-03-16 17:40 +0100
Re: [RFC PATCH v4 5/7] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-17 12:40 +0100
[RFC PATCH v4 4/7] PCI: Modify resource_alignment to support multiple devices Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-07 09:00 +0100
Re: [RFC PATCH v4 4/7] PCI: Modify resource_alignment to support multiple devices Alex Williamson <alex.williamson@redhat.com> - 2016-03-16 17:40 +0100
Re: [RFC PATCH v4 4/7] PCI: Modify resource_alignment to support multiple devices Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-17 12:30 +0100
Re: [RFC PATCH v4 4/7] PCI: Modify resource_alignment to support multiple devices Alex Williamson <alex.williamson@redhat.com> - 2016-03-17 13:50 +0100
Re: [RFC PATCH v4 4/7] PCI: Modify resource_alignment to support multiple devices Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-18 16:10 +0100
[RFC PATCH v4 3/7] PCI: Ignore resource_alignment if PCI_PROBE_ONLY was set Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-07 09:00 +0100
Re: [RFC PATCH v4 3/7] PCI: Ignore resource_alignment if PCI_PROBE_ONLY was set Alex Williamson <alex.williamson@redhat.com> - 2016-03-16 17:40 +0100
Re: [RFC PATCH v4 3/7] PCI: Ignore resource_alignment if PCI_PROBE_ONLY was set Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-17 12:40 +0100
[RFC PATCH v4 7/7] powerpc/powernv/pci-ioda: Add IOMMU_CAP_INTR_REMAP for IODA host bridge Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-07 09:00 +0100
Re: [RFC PATCH v4 7/7] powerpc/powernv/pci-ioda: Add IOMMU_CAP_INTR_REMAP for IODA host bridge Alex Williamson <alex.williamson@redhat.com> - 2016-03-16 17:40 +0100
Re: [RFC PATCH v4 7/7] powerpc/powernv/pci-ioda: Add IOMMU_CAP_INTR_REMAP for IODA host bridge Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-17 12:40 +0100
Re: [RFC PATCH v4 7/7] powerpc/powernv/pci-ioda: Add IOMMU_CAP_INTR_REMAP for IODA host bridge Alex Williamson <alex.williamson@redhat.com> - 2016-03-17 13:50 +0100
Re: [RFC PATCH v4 7/7] powerpc/powernv/pci-ioda: Add IOMMU_CAP_INTR_REMAP for IODA host bridge Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-18 13:00 +0100
Re: [RFC PATCH v4 0/7] vfio-pci: Allow to mmap sub-page MMIO BARs and MSI-X table Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-16 12:00 +0100
Re: [RFC PATCH v4 0/7] vfio-pci: Allow to mmap sub-page MMIO BARs and MSI-X table Bjorn Helgaas <helgaas@kernel.org> - 2016-03-16 15:20 +0100
Re: [RFC PATCH v4 0/7] vfio-pci: Allow to mmap sub-page MMIO BARs and MSI-X table Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-03-17 11:50 +0100
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