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| author | Matthew Rosato <mjrosato@linux.ibm.com> | 2022-10-28 15:47:58 -0400 |
|---|---|---|
| committer | Thomas Huth <thuth@redhat.com> | 2022-12-15 15:02:34 +0100 |
| commit | df202e3ff3fccb49868e08f20d0bda86cb953fbe (patch) | |
| tree | c6e920bdc5bd33071c4e0ecc7da2046b2f0269bf /hw/s390x | |
| parent | ef536007c3301bbd6a787e4c2210ea289adaa6f0 (diff) | |
| download | qemu-df202e3ff3fccb49868e08f20d0bda86cb953fbe.zip qemu-df202e3ff3fccb49868e08f20d0bda86cb953fbe.tar.gz qemu-df202e3ff3fccb49868e08f20d0bda86cb953fbe.tar.bz2 | |
s390x/pci: shrink DMA aperture to be bound by vfio DMA limit
Currently, s390x-pci performs accounting against the vfio DMA
limit and triggers the guest to clean up mappings when the limit
is reached. Let's go a step further and also limit the size of
the supported DMA aperture reported to the guest based upon the
initial vfio DMA limit reported for the container (if less than
than the size reported by the firmware/host zPCI layer). This
avoids processing sections of the guest DMA table during global
refresh that, for common use cases, will never be used anway, and
makes exhausting the vfio DMA limit due to mismatch between guest
aperture size and host limit far less likely and more indicitive
of an error.
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-Id: <20221028194758.204007-4-mjrosato@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Diffstat (limited to 'hw/s390x')
| -rw-r--r-- | hw/s390x/s390-pci-vfio.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c index 5f0adb0..f7bf36c 100644 --- a/hw/s390x/s390-pci-vfio.c +++ b/hw/s390x/s390-pci-vfio.c @@ -84,6 +84,7 @@ S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s, cnt->users = 1; cnt->avail = avail; QTAILQ_INSERT_TAIL(&s->zpci_dma_limit, cnt, link); + pbdev->iommu->max_dma_limit = avail; return cnt; } @@ -103,6 +104,7 @@ static void s390_pci_read_base(S390PCIBusDevice *pbdev, struct vfio_info_cap_header *hdr; struct vfio_device_info_cap_zpci_base *cap; VFIOPCIDevice *vpci = container_of(pbdev->pdev, VFIOPCIDevice, pdev); + uint64_t vfio_size; hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_BASE); @@ -122,6 +124,15 @@ static void s390_pci_read_base(S390PCIBusDevice *pbdev, /* The following values remain 0 until we support other FMB formats */ pbdev->zpci_fn.fmbl = 0; pbdev->zpci_fn.pft = 0; + + /* + * If appropriate, reduce the size of the supported DMA aperture reported + * to the guest based upon the vfio DMA limit. + */ + vfio_size = pbdev->iommu->max_dma_limit << TARGET_PAGE_BITS; + if (vfio_size < (cap->end_dma - cap->start_dma + 1)) { + pbdev->zpci_fn.edma = cap->start_dma + vfio_size - 1; + } } static bool get_host_fh(S390PCIBusDevice *pbdev, struct vfio_device_info *info, |