From: Nathan Chen <[email protected]> Update documentation now that "auto" is supported for accelerated SMMUv3 properties.
Reviewed-by: Eric Auger <[email protected]> Signed-off-by: Nathan Chen <[email protected]> --- qemu-options.hx | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/qemu-options.hx b/qemu-options.hx index 96ae41f787..d7e48688b5 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -1291,31 +1291,44 @@ SRST Enabling accel configures the host SMMUv3 in nested mode to support vfio-pci passthrough. - The following options are available when accel=on. - Note: 'auto' mode is not currently supported. + The following options will be set to auto by default if not manually + set. When accel=on and these properties are set to auto, the value is + derived from the host SMMUv3 capabilities via IOMMU_GET_HW_INFO. With + accel=on, this requires at least one cold-plugged vfio-pci device; if + none is present at machine init, QEMU will abort. - ``ril=on|off`` (default: on) + If accel=off, auto values resolve to the non-accel defaults given below. + + ``ril=on|off|auto`` (default: auto) Support for Range Invalidation, which allows the SMMUv3 driver to invalidate TLB entries for a range of IOVAs at once instead of issuing separate commands to invalidate each page. Must match with host SMMUv3 Range Invalidation support. - ``ats=on|off`` (default: off) + - With accel=off, auto is resolved to 'on'. + + ``ats=on|off|auto`` (default: auto) Support for Address Translation Services, which enables PCIe devices to cache address translations in their local TLB and reduce latency. Host SMMUv3 must support ATS in order to enable this feature for the vIOMMU. - ``oas=val`` (supported values are 44 and 48. default: 44) + - With accel=off, auto is resolved to 'off'. + + ``oas=val|auto`` (supported values are 44 and 48. default: auto) Sets the Output Address Size in bits. The value set here must be less than or equal to the host SMMUv3's supported OAS, so that the intermediate physical addresses (IPA) consumed by host SMMU for stage-2 translation do not exceed the host's max supported IPA size. - ``ssidsize=val`` (val between 0 and 20. default: 0) + - With accel=off, auto is resolved to 44. + + ``ssidsize=val|auto`` (val between 0 and 20. default: auto) Sets the Substream ID size in bits. When set to a non-zero value, PASID capability is advertised to the vIOMMU and accelerated use cases such as Shared Virtual Addressing (SVA) are supported. + - With accel=off, auto is resolved to 0. + ``-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: -- 2.43.0
