On 2/21/2025 7:38 AM, Michael S. Tsirkin wrote:
On Wed, Feb 12, 2025 at 05:44:49AM +0000, Suravee Suthikulpanit wrote:Current amd-iommu model internally creates an AMDVI-PCI device. Here is a snippet from info qtree: bus: main-system-bus type System dev: amd-iommu, id "" xtsup = false pci-id = "" intremap = "on" device-iotlb = false pt = true ... dev: q35-pcihost, id "" MCFG = -1 (0xffffffffffffffff) pci-hole64-size = 34359738368 (32 GiB) below-4g-mem-size = 134217728 (128 MiB) above-4g-mem-size = 0 (0 B) smm-ranges = true x-pci-hole64-fix = true x-config-reg-migration-enabled = true bypass-iommu = false bus: pcie.0 type PCIE dev: AMDVI-PCI, id "" addr = 01.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = -1 (0xffffffffffffffff) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) x-pcie-err-unc-mask = true x-pcie-ari-nextfn-1 = false x-max-bounce-buffer-size = 4096 (4 KiB) x-pcie-ext-tag = true busnr = 0 (0x0) class Class 0806, addr 00:01.0, pci id 1022:0000 (sub 1af4:1100) This prohibits users from specifying the PCI topology for the amd-iommu device, which becomes a problem when trying to support VM migration since it does not guarantee the same enumeration of AMD IOMMU device. Therfore, decouple the AMDVI-PCI from amd-iommu device and introduce pci-id parameter to link between the two devices. For example: -device AMDVI-PCI,id=iommupci0,bus=pcie.0,addr=0x05 \ -device amd-iommu,intremap=on,pt=on,xtsup=on,pci-id=iommupci0 \ For backward-compatibility, internally create the AMDVI-PCI device if not specified on the CLI. Co-developed-by: Daniel P. Berrangé<berra...@redhat.com> Signed-off-by: Suravee Suthikulpanit<suravee.suthikulpa...@amd.com>breaks build: https://gitlab.com/mstredhat/qemu/-/jobs/9202802751 ./hw/i386/amd_iommu.c: In function ‘amdvi_sysbus_realize’: ../hw/i386/amd_iommu.c:1616:18: error: unused variable ‘dc’ [-Werror=unused-variable] 1616 | DeviceClass *dc = (DeviceClass *) object_get_class(OBJECT(dev)); | ^~ cc1: all warnings being treated as errors
I'll send out v4 with the fix. Suravee
