> -----Original Message----- > From: Donald Dutile <ddut...@redhat.com> > Sent: Thursday, November 28, 2024 4:29 AM > To: Shameerali Kolothum Thodi > <shameerali.kolothum.th...@huawei.com>; Nicolin Chen > <nicol...@nvidia.com>; Eric Auger <eric.au...@redhat.com> > Cc: qemu-...@nongnu.org; qemu-devel@nongnu.org; > peter.mayd...@linaro.org; j...@nvidia.com; Linuxarm > <linux...@huawei.com>; Wangzhou (B) <wangzh...@hisilicon.com>; > jiangkunkun <jiangkun...@huawei.com>; Jonathan Cameron > <jonathan.came...@huawei.com>; zhangfei....@linaro.org > Subject: Re: [RFC PATCH 2/5] hw/arm/smmuv3: Add initial support for > SMMUv3 Nested device > > > >>> W.r.t naming, maybe something related to "hardware-accelerated"? > >>> > >> Given that 'accel' has been used for hw-acceleration elsewhere, that > seems > >> like a reasonable 'mode'. > >> But, it needs a paramater to state was is being accelerated. > >> i.e., the more global 'accel=kvm' has 'kvm'. > > > > I was thinking more like calling this hw accelerated nested SMMUv3 > emulation > > as 'smmuv3-accel'. This avoids confusion with the already existing > > 'iommu=smmuv3' that also has a nested emulation support. > > > > ie, > > -device arm-smmuv3-accel,id=smmuv1,bus=pcie.1 \ > > > I -think- you are saying below, that we have to think a bit more about this > device tagging. I'm thinking more like > - device arm-smmuv3,accel=<vcmdq>,id=smmu1,bus=pcie.1 \
Ok. But I think the initial suggestion to call this something else other than arm-smmuv3 came from the fact that it makes use of physical SMMUv3 nested stage support. This is required for vfio-pci assignment. So I used "accel" in that context. That is what I mean by basic functionality of this SMMUV3 device. If we need any additional accelerated feature support then that can be provided as "properties" on top of this. Like, - device arm-smmuv3-accel,id=smmu1,bus=pcie.1,vcmdq=on \ Or may be as Nicolin's suggestion(without explicit "vcmdq") of probing for vCMDQ support transparently and falling back to basic support if not available. I prefer the first one which gives an option to turn off if required. But don’t have any strong opinion either way. Thanks, Shameer.
