On 25 July 2018 at 11:40, Andrew Jones <drjo...@redhat.com> wrote: > On Wed, Jul 25, 2018 at 11:20:03AM +0200, Ard Biesheuvel wrote: >> On 25 July 2018 at 11:17, Hongbo Zhang <hongbo.zh...@linaro.org> wrote: >> > On 25 July 2018 at 17:13, Ard Biesheuvel <ard.biesheu...@linaro.org> wrote: >> >> On 25 July 2018 at 11:09, Hongbo Zhang <hongbo.zh...@linaro.org> wrote: >> >>> On 25 July 2018 at 17:01, Ard Biesheuvel <ard.biesheu...@linaro.org> >> >>> wrote: >> >>>> On 25 July 2018 at 10:48, Daniel P. Berrangé <berra...@redhat.com> >> >>>> wrote: >> >>>>> On Wed, Jul 25, 2018 at 01:30:52PM +0800, Hongbo Zhang wrote: >> >>>>>> For the Aarch64, there is one machine 'virt', it is primarily meant to >> >>>>>> run on KVM and execute virtualization workloads, but we need an >> >>>>>> environment as faithful as possible to physical hardware, for >> >>>>>> supporting >> >>>>>> firmware and OS development for pysical Aarch64 machines. >> >>>>>> >> >>>>>> This patch introduces new machine type 'Enterprise' with main >> >>>>>> features: >> >>>>> >> >>>>> The 'enterprise' name is really awful - this is essentially a marketing >> >>>>> term completely devoid of any useful meaning. >> >>>>> >> >>>>> You had previously called this "sbsa" which IIUC was related to a real >> >>>>> world hardware specification that it was based on. IOW, I think this >> >>>>> old >> >>>>> name was preferrable to calling it "enterprise". >> >>>>> >> >>>> >> >>>> I couldn't agree more. However, IIUC this change was made at the >> >>>> request of one of the reviewers, although I wasn't part of the >> >>>> discussion at that point, so I'm not sure who it was. >> >>>> >> >>>> Hongbo, could you please share a link to that discussion? >> >>>> >> >>>> Thanks, >> >>>> Ard. >> >>>> >> >>> >> >>> V1 discussion here: >> >>> https://www.mail-archive.com/qemu-devel@nongnu.org/msg545775.html >> >>> >> >> >> >> So who asked for the sbsa -> enterprise change? >> > >> > Actually nobody, but it was argued that sbsa does not require ehci and >> > ahci etc, then we should find a name fitting for this platform better. >> >> That doesn't make sense to me. The SBSA describes a minimal >> configuration, it does not limit what peripherals may be attached to >> the core system. >> > > Hi Ard, > > I think that a machine model named 'sbsa' should provide all SBSA required > hardware, and nothing else, while providing a means to easily extend the > machine beyond that in any way the user likes. The user can easily add > devices with the command line and/or by using -readconfig to build a > "typical" machine. Note, it should even be possible to add, e.g. an ACHI > controller, to the memory map using the platform bus, if that's preferred > over PCIe. >
The purpose of the SBSA machine is not to provide a minimal configuration. It is intended to exercise all the moving parts one might find in a server firmware/OS stack, including pieces that are not usually found on x86 machines, such as DRAM starting above 4 GB and SATA/USB controllers that are not PCIe based. If we start layering the usual components on top, it is highly likely that checking the EHCI box gives you a PCI based USB2 controller, partially defeating the purpose of the exercise. -- Ard.