>-----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. Thanks Zhenzhong
