Re: [PATCH v6 0/7] hw/arm/virt: Improve address assignment for high memory regions

[Gavin Shan]

Hi Marc,

On 10/29/22 7:29 PM, Marc Zyngier wrote:
> On Wed, 26 Oct 2022 01:29:56 +0100,
> Gavin Shan <gshan@redhat.com> wrote:
> > On 10/24/22 11:54 AM, Gavin Shan wrote:
> > > There are three high memory regions, which are VIRT_HIGH_REDIST2,
> > > VIRT_HIGH_PCIE_ECAM and VIRT_HIGH_PCIE_MMIO. Their base addresses
> > > are floating on highest RAM address. However, they can be disabled
> > > in several cases.
> > >
> > > (1) One specific high memory region is disabled by developer by
> > >       toggling vms->highmem_{redists, ecam, mmio}.
> > >
> > > (2) VIRT_HIGH_PCIE_ECAM region is disabled on machine, which is
> > >       'virt-2.12' or ealier than it.
> > >
> > > (3) VIRT_HIGH_PCIE_ECAM region is disabled when firmware is loaded
> > >       on 32-bits system.
> > >
> > > (4) One specific high memory region is disabled when it breaks the
> > >       PA space limit.
> > >
> > > The current implementation of virt_set_memmap() isn't comprehensive
> > > because the space for one specific high memory region is always
> > > reserved from the PA space for case (1), (2) and (3). In the code,
> > > 'base' and 'vms->highest_gpa' are always increased for those three
> > > cases. It's unnecessary since the assigned space of the disabled
> > > high memory region won't be used afterwards.
> > >
> > > The series intends to improve the address assignment for these
> > > high memory regions and introduces new properties for user to
> > > selectively disable those 3 high memory regions.
> > >
> > > PATCH[1-4] preparatory work for the improvment
> > > PATCH[5]   improve high memory region address assignment
> > > PATCH[6]   adds 'compact-highmem' to enable or disable the optimization
> > > PATCH[7]   adds properties so that high memory regions can be disabled
> > >
> > > v5: https://lists.nongnu.org/archive/html/qemu-arm/2022-10/msg00280.html
> > > v4: https://lists.nongnu.org/archive/html/qemu-arm/2022-10/msg00067.html
> > > v3: https://lists.nongnu.org/archive/html/qemu-arm/2022-09/msg00258.html
> > > v2: https://lore.kernel.org/all/20220815062958.100366-1-gshan@redhat.com/T/
> > > v1: https://lists.nongnu.org/archive/html/qemu-arm/2022-08/msg00013.html
> >
> > Could you help to take a look when getting a chance? I think Connie and
> > Eric are close to complete the reviews, but v7 is still needed to address
> > extra comments from them. I hope to make v7 mergeable if possible :)
>
> With the comments from Connie and Eric addressed, this looks good to
> me:
>
> Reviewed-by: Marc Zyngier <maz@kernel.org>
>
> Thanks for having gone the extra mile on this one.

Thank you for your feedback and reviews. I've posted v7 with your r-b
after resolving comments from Connie/Eric.

https://lists.nongnu.org/archive/html/qemu-arm/2022-10/msg00693.html (v7)

Thanks,
Gavin