> -----Original Message-----
> From: Nathan Chen <[email protected]>
> Sent: 12 May 2026 20:35
> To: [email protected]; [email protected]
> Cc: Eric Auger <[email protected]>; Peter Maydell
> <[email protected]>; Philippe Mathieu-Daudé <[email protected]>;
> Zhao Liu <[email protected]>; Matt Ochs <[email protected]>; Nicolin
> Chen <[email protected]>; Shameer Kolothum Thodi
> <[email protected]>; Nathan Chen <[email protected]>
> Subject: [PATCH v3 7/7] qemu-options.hx: Support "auto" for accel SMMUv3
> properties
>
> From: Nathan Chen <[email protected]>
>
> Update documentation now that "auto" is supported for accelerated
> SMMUv3 properties.
>
> 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..46b02a1bb3 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1291,30 +1291,43 @@ 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.
> + - With accel=on, auto means the value is automatically derived from
> the
> host SMMU.
> + - With accel=off, auto is resolved to 'on'.
If the intention here is to have bullet points for above, you might need a blank
line before "-" . Please see how this gets rendered in html format and
adjust.
Same for others below.
Thanks,
Shameer
>
> - ``ats=on|off`` (default: off)
> + ``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.
> + - With accel=on, auto means the value is automatically derived from
> the
> host SMMU.
> + - With accel=off, auto is resolved to 'off'.
>
> - ``oas=val`` (supported values are 44 and 48. default: 44)
> + ``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.
> + - With accel=on, auto means the value is automatically derived from
> the
> host SMMU.
> + - With accel=off, auto is resolved to 44.
>
> - ``ssidsize=val`` (val between 0 and 20. default: 0)
> + ``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=on, auto means the value is automatically derived from
> the
> host SMMU.
> + - With accel=off, auto is resolved to 0.
>
> ``-device amd-iommu[,option=...]``
> Enables emulation of an AMD-Vi I/O Memory Management Unit (IOMMU).
> --
> 2.43.0
