On Tue, 2026-03-10 at 03:16 +0000, Duan, Zhenzhong wrote: > > > > > -----Original Message----- > > From: Daniel P. Berrangé <[[email protected]](mailto:[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]](mailto:[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.
Hi, Indeed, this would be nice if we could. > > Thanks > Zhenzhong
