On 10/3/26 04:16, Duan, Zhenzhong wrote:
-----Original Message-----
From: Daniel P. Berrangé <[email protected]>
Subject: Re: [PATCH] intel_iommu: Remove 'x-' prefix from 'x-scalable-mode' and
'x-flts' properties
On Mon, Mar 09, 2026 at 01:44:15PM +0100, Philippe Mathieu-Daudé wrote:
Hi,
On 9/3/26 10:20, Zhenzhong Duan wrote:
We had 'x-scalable-mode' for more than 5 years and 'x-flts' for more than 1
year, it's fine to remove 'x-' now.
This is a prerequisite to enable intel_iommu's scalable mode and first stage
translation support in libvirt.
Signed-off-by: Zhenzhong Duan <[email protected]>
---
docs/devel/vfio-iommufd.rst | 10 +++++-----
hw/i386/intel_iommu.c | 8 ++++----
hw/i386/intel_iommu_accel.c | 4 ++--
tests/qtest/intel-iommu-test.c | 2 +-
4 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/docs/devel/vfio-iommufd.rst b/docs/devel/vfio-iommufd.rst
index 78bcdffac7..5755532443 100644
--- a/docs/devel/vfio-iommufd.rst
+++ b/docs/devel/vfio-iommufd.rst
@@ -153,22 +153,22 @@ RAM discarding for mdev.
``vfio-ap`` and ``vfio-ccw`` devices don't have same issue as their backend
devices are always mdev and RAM discarding is force enabled.
-Usage with intel_iommu featuring x-flts=on
+Usage with intel_iommu featuring flts=on
------------------------------------------
Only IOMMUFD backed VFIO device is supported when intel_iommu is
configured
-with x-flts=on, for legacy container backed VFIO device, below error shows:
+with flts=on, for legacy container backed VFIO device, below error shows:
.. code-block:: none
- qemu-system-x86_64: -device vfio-pci,host=0000:02:00.0: vfio
0000:02:00.0: Failed to set vIOMMU: Need IOMMUFD backend when x-flts=on
+ qemu-system-x86_64: -device vfio-pci,host=0000:02:00.0: vfio
0000:02:00.0: Failed to set vIOMMU: Need IOMMUFD backend when flts=on
VFIO device under PCI bridge is unsupported, use PCIE bridge if necessary,
otherwise below error shows:
.. code-block:: none
- qemu-system-x86_64: -device vfio-
pci,host=0000:02:00.0,bus=bridge1,iommufd=iommufd0: vfio 0000:02:00.0: Failed
to set vIOMMU: Host device downstream to a PCI bridge is unsupported when x-
flts=on
+ qemu-system-x86_64: -device vfio-
pci,host=0000:02:00.0,bus=bridge1,iommufd=iommufd0: vfio 0000:02:00.0: Failed
to set vIOMMU: Host device downstream to a PCI bridge is unsupported when
flts=on
If host IOMMU has ERRATA_772415_SPR17, running guest with
"intel_iommu=on,sm_off"
is unsupported, kexec or reboot guest from "intel_iommu=on,sm_on" to
@@ -177,4 +177,4 @@ below if it's not needed by guest:
.. code-block:: bash
- -device intel-iommu,x-scalable-mode=off
+ -device intel-iommu,scalable-mode=off
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index d24ba989bf..001847ad37 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -4200,8 +4200,8 @@ static const Property vtd_properties[] = {
DEFINE_PROP_UINT8("aw-bits", IntelIOMMUState, aw_bits,
VTD_HOST_ADDRESS_WIDTH),
DEFINE_PROP_BOOL("caching-mode", IntelIOMMUState, caching_mode,
FALSE),
- DEFINE_PROP_BOOL("x-scalable-mode", IntelIOMMUState,
scalable_mode, FALSE),
- DEFINE_PROP_BOOL("x-flts", IntelIOMMUState, fsts, FALSE),
IMHO safer would be to officially deprecate these in
docs/about/deprecated.rst and keeping them aliased until deprecation
period expires. Other changes LGTM.
The purpose of using an 'x-' prefix for properties in QEMU is to declare
that they are subject to change with no warning, so we are free to change
them without any deprecation IMHO.
Does that mean I can add another patch to s/flts/fsts opportunistically?
flts(first level translation support) is a naming based on old version vtd spec,
in new spec, it changed to use fsts(first stage translation support) naming.
Apparently :) You should post a v2 with that change included.
