Hi Zhenzhong,
On 7/8/25 1:05 PM, Zhenzhong Duan wrote:
> Currently we don't support nested translation for passthrough device with
> emulated device under same PCI bridge, because they require different address
> space when x-flts=on.
>
> In theory, we do support if devices under same PCI bridge are all passthrough
> devices. But emulated device can be hotplugged under same bridge. For
> simplify,
to simplify
> just forbid passthrough device under PCI bridge no matter if there is, or will
> be emulated devices under same bridge. This is acceptable because PCIE bridge
> is more popular than PCI bridge now.
>
> Suggested-by: Yi Liu <yi.l....@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
> ---
> hw/i386/intel_iommu.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index c57ca02cdd..15f4393d6f 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -4330,9 +4330,10 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s,
> PCIBus *bus,
> return vtd_dev_as;
> }
>
> -static bool vtd_check_hiod(IntelIOMMUState *s, HostIOMMUDevice *hiod,
> +static bool vtd_check_hiod(IntelIOMMUState *s, VTDHostIOMMUDevice *vtd_hiod,
> Error **errp)
> {
> + HostIOMMUDevice *hiod = vtd_hiod->hiod;
> HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
> int ret;
>
> @@ -4359,6 +4360,8 @@ static bool vtd_check_hiod(IntelIOMMUState *s,
> HostIOMMUDevice *hiod,
> #ifdef CONFIG_IOMMUFD
> struct HostIOMMUDeviceCaps *caps = &hiod->caps;
> struct iommu_hw_info_vtd *vtd = &caps->vendor_caps.vtd;
> + PCIBus *bus = vtd_hiod->bus;
> + PCIDevice *pdev = pci_find_device(bus, pci_bus_num(bus),
> vtd_hiod->devfn);
>
> /* Remaining checks are all stage-1 translation specific */
> if (!object_dynamic_cast(OBJECT(hiod), TYPE_HOST_IOMMU_DEVICE_IOMMUFD)) {
> @@ -4381,6 +4384,12 @@ static bool vtd_check_hiod(IntelIOMMUState *s,
> HostIOMMUDevice *hiod,
> error_setg(errp, "Stage-1 1GB huge page is unsupported by host
> IOMMU");
> return false;
> }
> +
> + if (pci_device_get_iommu_bus_devfn(pdev, &bus, NULL, NULL)) {
> + error_setg(errp, "Host device under PCI bridge is unsupported "
> + "when x-flts=on");
> + return false;
> + }
> #endif
>
> error_setg(errp, "host IOMMU is incompatible with stage-1 translation");
> @@ -4414,7 +4423,7 @@ static bool vtd_dev_set_iommu_device(PCIBus *bus, void
> *opaque, int devfn,
> vtd_hiod->iommu_state = s;
> vtd_hiod->hiod = hiod;
>
> - if (!vtd_check_hiod(s, hiod, errp)) {
> + if (!vtd_check_hiod(s, vtd_hiod, errp)) {
> g_free(vtd_hiod);
> vtd_iommu_unlock(s);
> return false;
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Eric
