[v3,0/5] target/arm: Reduced-IPA space and highmem=off fixes

Message

Marc Zyngier Dec. 27, 2021, 9:16 p.m. UTC

Here's another stab at enabling QEMU on systems with pathologically
reduced IPA ranges such as the Apple M1 (previous version at [1]).
Eventually, we're able to run a KVM guest with more than just 3GB of
RAM on a system with a 36bit IPA space, and at most 123 vCPUs.

This series does a few things:
- decouple the enabling of the highmem PCIe region from the highmem
  attribute
- introduce a new attribute to control the enabling of the highmem
  GICv3 redistributors
- correctly cap the PA range with highmem is off
- generalise the highmem behaviour to any PA range
- disable both highmem PCIe and GICv3 RDs when they are outside of the
  PA range

This has been tested on an M1-based Mac-mini running Linux v5.16-rc6
with both KVM and TCG.

* From v2:
  - Fixed checking of the maximum memory against the IPA space
  - Fixed TCG memory map creation
  - Rebased on top of QEMU's 89f3bfa326
  - Collected Andrew's RBs, with thanks

[1] https://lore.kernel.org/r/[e-mail]

Marc Zyngier (5):
  hw/arm/virt: Key enablement of highmem PCIe on highmem_ecam
  hw/arm/virt: Add a control for the the highmem redistributors
  hw/arm/virt: Honor highmem setting when computing the memory map
  hw/arm/virt: Use the PA range to compute the memory map
  hw/arm/virt: Disable highmem devices that don't fit in the PA range

 hw/arm/virt-acpi-build.c | 12 +++----
 hw/arm/virt.c            | 67 ++++++++++++++++++++++++++++++++++------
 include/hw/arm/virt.h    |  4 ++-
 3 files changed, 67 insertions(+), 16 deletions(-)