| Message ID | 1457336918-3893-7-git-send-email-xyjxie@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
[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. 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? > x_start = vdev->msix_offset; > x_end = vdev->msix_offset + vdev->msix_size; > } -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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) { 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) { x_start = vdev->msix_offset; x_end = vdev->msix_offset + vdev->msix_size; }
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(-)