No configuration will enable IOMMU

I have a dell r630 and I can't get proxmox to use iommu.
Proxmox keeps giving this error: "TASK ERROR: cannot prepare PCI pass-through, IOMMU not present"

I've followed the advice of multiple threads, yet this is the result of
# cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-6.2.16-3-pve root=/dev/mapper/pve-root ro quiet

And this is dmesg:
# dmesg | grep -e DMAR -e IOMMU
[ 0.008870] ACPI: DMAR 0x000000007BAFE000 0000F8 (v01 DELL PE_SC3 00000001 DELL 00000001)
[ 0.008900] ACPI...

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