On 12 March 2018 at 06:19, Daniil Egranov <daniil.egra...@arm.com> wrote: > Hello Ard, > > On 03/08/2018 02:29 AM, Ard Biesheuvel wrote: >> >> Hello Daniil, >> >> Could you please use a text based email client? Gmail does not >> consider the indentation as threading, so the context below is >> unintelligible >> > > I forced Thunderbird to plain text. I assumed it should follow a previous > email composition style. At least i did not have problem with it so far. I > hope it's formated correctly now. >
Thanks. > >> On 8 March 2018 at 08:21, Daniil Egranov <daniil.egra...@arm.com> wrote: >>> >>> Hello Ard, >>> >>> Thanks for reply. Please see my comments below. >>> >>> On 03/07/2018 02:03 AM, Ard Biesheuvel wrote: >>> >>> (+ Laszlo) >>> >>> Hello Daniil, >>> >>> On 7 March 2018 at 01:36, Daniil Egranov <daniil.egra...@arm.com> wrote: >>> >>> This is an attempt to add MMIO Virtio devices into the >>> non-discoverable device registration procedure and allow >>> Virtio PCI drivers to recognize and program such devices >>> correctly. >>> >>> Why? The purpose of the non-discoverable device layer is to make >>> non-PCI controllers that can be driven by PCI class drivers appear as >>> PCI devices. We have started using the base non-discoverable device >>> protocol for other devices as well, but the PCI wrapper is really only >>> intended for PCI class drivers. >>> >>> >>> I am looking for a proper way to handle multiple MMIO Virtio devices on a >>> single platform. As both PCI and MMIO types of Virtio device programmed >>> in >>> about the same way, non-discoverable devices approach was looking valid. >>> >>> I understand you point. Correct me if I am wrong but all non-discoverable >>> devices are MMIO devices so if there is PCI version of the device exists, >>> PCI wrapper can be used. The Virtio PCI class devices are using >>> VirtioPciDeviceDxe driver. Is this driver not fitting to the category of >>> PCI >>> class drivers? >>> >> >> That is not the point. The Intel guys have decided that the AHCI, XHCI >> and other drivers (whose specs do no mandate PCI) are implemented as >> PCI drivers only, which means that they are essentially combining two >> layers of the driver stack (the PCI part and the _HCI part) >> >> Splitting all of those drivers into PCI drivers that produce _HCI >> protocols and _HCI drivers that produce the USB host, SATA host, etc >> protocols is not going to be accepted by upstream EDK2, so instead, we >> decided to turn the PCI 'emulation' that was duplicated across many >> platforms into a proper abstraction. >> >> In the virtio case, we don't have that problem. We have MMIO and PCI >> support using drivers that use the proper abstractions, and so >> presenting MMIO devices as PCI devices is really a step backwards. >> > > I see, thanks for details. > >> What are you trying to achieve that the current code won't let you? >> > > I have a situation when a platform has multiple Virtio MMIO devices. The > initial way to handle them was installing a device path protocol and calling > VirtioMmioDeviceLib for each device as part of the platform DXE driver. The > non-discoverable way was hiding all these operations and was looking like > more clean approach. Well, that is only true because you are using NonDiscoverableDeviceRegistrationLib, which encapsulates those exact same things. > In case of multiple Virtio MMIO devices, what will be a proper way to handle > them? > _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
