Xen project Mailing List

BUG during vgic3 ITS mapping

To: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>

From: Jason Andryuk <jason.andryuk@xxxxxxx>

Date: Wed, 9 Jul 2025 11:16:32 -0400

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Cc: <Mykyta_Poturai@xxxxxxxx>, <rahul.singh@xxxxxxx>, Stewart Hildebrand <stewart.hildebrand@xxxxxxx>

Delivery-date: Wed, 09 Jul 2025 15:16:46 +0000

List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

Hi, I'm running Xen in QEMU with vgic3 and started hitting: (XEN) Xen BUG at drivers/passthrough/arm/iommu_helpers.c:49 BUG_ON(!is_domain_direct_mapped(d));

I'm using dmo0less to create a split hardware and control domains. That

means hwdom is not direct mapped, but is_iommu_enabled() is true. It

looks to be caused by the new call to iommu_map() in:

commit f9f6b22abf1d8d88c97fbc9925b274c0bb4ac881 Author: Rahul Singh <rahul.singh@xxxxxxx> Date: Wed Jul 2 07:10:03 2025 +0000 xen/arm: Map ITS doorbell register to IOMMU page tables Thoughts on how to address this? Thanks, Jason

(XEN) Loading d1 initrd from 0000000045800000 to

0x0000000048200000-0x000000004bdcd615

(XEN) Loading d1 DTB to 0x0000000048000000-0x00000000480005c4 (XEN) Xen BUG at drivers/passthrough/arm/iommu_helpers.c:49 (XEN) ----[ Xen-4.21-unstable arm64 debug=y Tainted: I ]---- (XEN) CPU: 0 (XEN) PC: 00000a000024c758 arm_iommu_map_page+0x80/0x90 (XEN) LR: 00000a000024c750 (XEN) SP: 00000a000032fb70 (XEN) CPSR: 0000000080000249 MODE:64-bit EL2h (Hypervisor, handler) ... (XEN) Xen call trace: (XEN) [<00000a000024c758>] arm_iommu_map_page+0x80/0x90 (PC) (XEN) [<00000a000024c750>] arm_iommu_map_page+0x78/0x90 (LR) (XEN) [<00000a0000250884>] iommu_map+0xcc/0x29c (XEN) [<00000a0000288024>] vgic_v3_its_init_domain+0x18c/0x1e8 (XEN) [<00000a0000285228>] vgic-v3.c#vgic_v3_domain_init+0x168/0x21c (XEN) [<00000a0000281dcc>] domain_vgic_init+0x14c/0x210 (XEN) [<00000a00002705a4>] arch_domain_create+0x150/0x1f0 (XEN) [<00000a00002055e8>] domain_create+0x47c/0x6c0 (XEN) [<00000a00002cf090>] create_domUs+0x7f8/0x8cc (XEN) [<00000a00002eb588>] start_xen+0x8f4/0x998 (XEN) [<00000a000020018c>] head.o#primary_switched+0x4/0x10 (XEN) (XEN) (XEN) **************************************** (XEN) Panic on CPU 0: (XEN) Xen BUG at drivers/passthrough/arm/iommu_helpers.c:49 (XEN) **************************************** (XEN) (XEN) Reboot in five seconds...

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