diff options
| author | Kunkun Jiang <jiangkunkun@huawei.com> | 2021-10-27 17:04:05 +0800 |
|---|---|---|
| committer | Alex Williamson <alex.williamson@redhat.com> | 2021-11-01 12:17:51 -0600 |
| commit | f36d4fb85f41604038386e1eb4295acd7d372d86 (patch) | |
| tree | a011c8a5774a6ee32c27b393c9ac3312a7e1e1af /hw/vfio/pci.c | |
| parent | af531756d25541a1b3b3d9a14e72e7fedd941a2e (diff) | |
vfio/pci: Add support for mmapping sub-page MMIO BARs after live migration
We can expand MemoryRegions of sub-page MMIO BARs in
vfio_pci_write_config() to improve IO performance for some
devices. However, the MemoryRegions of destination VM are
not expanded any more after live migration. Because their
addresses have been updated in vmstate_load_state()
(vfio_pci_load_config) and vfio_sub_page_bar_update_mapping()
will not be called.
This may result in poor performance after live migration.
So iterate BARs in vfio_pci_load_config() and try to update
sub-page BARs.
Reported-by: Nianyao Tang <tangnianyao@huawei.com>
Reported-by: Qixin Gan <ganqixin@huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
Link: https://lore.kernel.org/r/20211027090406.761-2-jiangkunkun@huawei.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'hw/vfio/pci.c')
| -rw-r--r-- | hw/vfio/pci.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 5cdf1d4298..7b45353ce2 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -2453,7 +2453,12 @@ static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f) { VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev); PCIDevice *pdev = &vdev->pdev; - int ret; + pcibus_t old_addr[PCI_NUM_REGIONS - 1]; + int bar, ret; + + for (bar = 0; bar < PCI_ROM_SLOT; bar++) { + old_addr[bar] = pdev->io_regions[bar].addr; + } ret = vmstate_load_state(f, &vmstate_vfio_pci_config, vdev, 1); if (ret) { @@ -2463,6 +2468,18 @@ static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f) vfio_pci_write_config(pdev, PCI_COMMAND, pci_get_word(pdev->config + PCI_COMMAND), 2); + for (bar = 0; bar < PCI_ROM_SLOT; bar++) { + /* + * The address may not be changed in some scenarios + * (e.g. the VF driver isn't loaded in VM). + */ + if (old_addr[bar] != pdev->io_regions[bar].addr && + vdev->bars[bar].region.size > 0 && + vdev->bars[bar].region.size < qemu_real_host_page_size) { + vfio_sub_page_bar_update_mapping(pdev, bar); + } + } + if (msi_enabled(pdev)) { vfio_msi_enable(vdev); } else if (msix_enabled(pdev)) { |