From: Alejandro Jimenez Date: Fri, 19 Sep 2025 21:34:55 +0000 (+0000) Subject: amd_iommu: Document '-device amd-iommu' common options X-Git-Tag: v10.2.0-rc1~76^2~25 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=918973f1d476a62922761c9a5484b309491b652c;p=thirdparty%2Fqemu.git amd_iommu: Document '-device amd-iommu' common options Document the common parameters used when emulating AMD vIOMMU. Besides the two amd-iommu specific options: 'xtsup' and 'dma-remap', the the generic x86 IOMMU option 'intremap' is also included, since it is typically specified in QEMU command line examples and mailing list threads. Signed-off-by: Alejandro Jimenez Reviewed-by: Michael S. Tsirkin Message-ID: <20250919213515.917111-3-alejandro.j.jimenez@oracle.com> Signed-off-by: Michael S. Tsirkin --- diff --git a/qemu-options.hx b/qemu-options.hx index 3ff10ec09d..9b4e870350 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -1238,6 +1238,29 @@ SRST Accepts either the default root complex (pcie.0) or a pxb-pcie based root complex. +``-device amd-iommu[,option=...]`` + Enables emulation of an AMD-Vi I/O Memory Management Unit (IOMMU). + Only available with ``-machine q35``, it supports the following options: + + ``dma-remap=on|off`` (default: off) + Support for DMA address translation and access permission checking for + guests attaching passthrough devices to paging domains, using the AMD v1 + I/O Page Table format. This enables ``-device vfio-pci,...`` to work + correctly with a guest using the DMA remapping feature of the vIOMMU. + + ``intremap=on|off`` (default: auto) + Generic x86 IOMMU functionality implemented by ``amd-iommu`` device. + Enables interrupt remapping feature in guests, which is also required to + enable x2apic support. + Currently only available with ``kernel-irqchip=off|split``, it is + automatically enabled when either of those modes is in use, and disabled + with ``kernel-irqchip=on``. + + ``xtsup=on|off`` (default: off) + Interrupt remapping table supports x2apic mode, enabling the use of + 128-bit IRTE format with 32-bit destination field by the guest. Required + to support routing interrupts to vCPUs with APIC IDs larger than 0xff. + ERST DEF("name", HAS_ARG, QEMU_OPTION_name,