On Thu, Jan 4, 2024 at 1:04 PM Russell King (Oracle) <linux@xxxxxxxxxxxxxxx> wrote: > > On Thu, Jan 04, 2024 at 11:34:48AM +0000, Marc Zyngier wrote: > > On Wed, 03 Jan 2024 13:43:16 +0000, > > "Rafael J. Wysocki" <rafael@xxxxxxxxxx> wrote: > > > > > > On Wed, Dec 27, 2023 at 12:00 PM Lorenzo Pieralisi > > > <lpieralisi@xxxxxxxxxx> wrote: > > > > > > > > This series is v4 of previous series: > > > > > > > > v3: https://lore.kernel.org/all/20231006125929.48591-1-lpieralisi@xxxxxxxxxx > > > > v2: https://lore.kernel.org/all/20230906094139.16032-1-lpieralisi@xxxxxxxxxx > > > > v1: https://lore.kernel.org/all/20230905104721.52199-1-lpieralisi@xxxxxxxxxx > > > > > > > > v3 -> v4: > > > > - Dropped patches [1-3], already merged > > > > - Added Linuxized ACPICA changes accepted upstream > > > > - Rebased against v6.7-rc3 > > > > > > > > v2 -> v3: > > > > - Added ACPICA temporary changes and ACPI changes to implement > > > > ECR https://bugzilla.tianocore.org/show_bug.cgi?id=4557 > > > > - ACPI changes are for testing purposes - subject to ECR code > > > > first approval > > > > > > > > v1 -> v2: > > > > - Updated DT bindings as per feedback > > > > - Updated patch[2] to use GIC quirks infrastructure > > > > > > > > Original cover letter > > > > --- > > > > The GICv3 architecture specifications provide a means for the > > > > system programmer to set the shareability and cacheability > > > > attributes the GIC components (redistributors and ITSes) use > > > > to drive memory transactions. > > > > > > > > Albeit the architecture give control over shareability/cacheability > > > > memory transactions attributes (and barriers), it is allowed to > > > > connect the GIC interconnect ports to non-coherent memory ports > > > > on the interconnect, basically tying off shareability/cacheability > > > > "wires" and de-facto making the redistributors and ITSes non-coherent > > > > memory observers. > > > > > > > > This series aims at starting a discussion over a possible solution > > > > to this problem, by adding to the GIC device tree bindings the > > > > standard dma-noncoherent property. The GIC driver uses the property > > > > to force the redistributors and ITSes shareability attributes to > > > > non-shareable, which consequently forces the driver to use CMOs > > > > on GIC memory tables. > > > > > > > > On ARM DT DMA is default non-coherent, so the GIC driver can't rely > > > > on the generic DT dma-coherent/non-coherent property management layer > > > > (of_dma_is_coherent()) which would default all GIC designs in the field > > > > as non-coherent; it has to rely on ad-hoc dma-noncoherent property handling. > > > > > > > > When a consistent approach is agreed upon for DT an equivalent binding will > > > > be put forward for ACPI based systems. > > > > > > > > Lorenzo Pieralisi (3): > > > > ACPICA: MADT: Add GICC online capable bit handling > > > > ACPICA: MADT: Add new MADT GICC/GICR/ITS non-coherent flags handling > > > > irqchip/gic-v3: Enable non-coherent redistributors/ITSes ACPI probing > > > > > > > > drivers/acpi/processor_core.c | 21 +++++++++++++++++++++ > > > > drivers/irqchip/irq-gic-common.h | 8 ++++++++ > > > > drivers/irqchip/irq-gic-v3-its.c | 4 ++++ > > > > drivers/irqchip/irq-gic-v3.c | 9 +++++++++ > > > > include/acpi/actbl2.h | 12 ++++++++++-- > > > > include/linux/acpi.h | 3 +++ > > > > 6 files changed, 55 insertions(+), 2 deletions(-) > > > > > > > > -- > > > > > > I can apply the first 2 patches, but I would need an ACK for the 3rd one. > > > > > > Alternatively, feel free to add > > > > > > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > > > to the first 2 patches and route them via ARM64. > > > > Thanks for that. I have some comments on the third patch, which I'd > > like to see addressed beforehand. This is probably all 6.9 material > > anyway (nobody is affected by this so far). > > From a purely selfish point of view, it would be useful to have the > first patch merged merely to reduce the burden of patches for vcpu > hotplug. OK, since there will be at least one more iteration of patch [3/3] AFAICS, I'll queue up patches [1-2/3] for 6.8 (next week, though).
