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pci: advertise a page aligned ATS

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After Linux kernel commit 61363c1474b1 ("iommu/vt-d: Enable ATS only
if the device uses page aligned address."), ATS will be only enabled
if device advertises a page aligned request.

Unfortunately, vhost-net is the only user and we don't advertise the
aligned request capability in the past since both vhost IOTLB and
address_space_get_iotlb_entry() can support non page aligned request.

Though it's not clear that if the above kernel commit makes
sense. Let's advertise a page aligned ATS here to make vhost device
IOTLB work with Intel IOMMU again.

Note that in the future we may extend pcie_ats_init() to accept
parameters like queue depth and page alignment.

Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20200909081731.24688-1-jasowang@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2020-09-09 16:17:31 +08:00 committed by Michael S. Tsirkin
parent 0259c78ca7
commit 4c70875372
1 changed files with 3 additions and 2 deletions
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5
hw/pci/pcie.c
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@ -971,8 +971,9 @@ void pcie_ats_init(PCIDevice *dev, uint16_t offset)
dev->exp.ats_cap = offset;
/* Invalidate Queue Depth 0, Page Aligned Request 0 */
pci_set_word(dev->config + offset + PCI_ATS_CAP, 0);
/* Invalidate Queue Depth 0, Page Aligned Request 1 */
pci_set_word(dev->config + offset + PCI_ATS_CAP,
PCI_ATS_CAP_PAGE_ALIGNED);
/* STU 0, Disabled by default */
pci_set_word(dev->config + offset + PCI_ATS_CTRL, 0);