xemu/docs
Gavin Shan f40408a9fe hw/arm/virt: Add 'compact-highmem' property
After the improvement to high memory region address assignment is
applied, the memory layout can be changed, introducing possible
migration breakage. For example, VIRT_HIGH_PCIE_MMIO memory region
is disabled or enabled when the optimization is applied or not, with
the following configuration. The configuration is only achievable by
modifying the source code until more properties are added to allow
users selectively disable those high memory regions.

  pa_bits              = 40;
  vms->highmem_redists = false;
  vms->highmem_ecam    = false;
  vms->highmem_mmio    = true;

  # qemu-system-aarch64 -accel kvm -cpu host    \
    -machine virt-7.2,compact-highmem={on, off} \
    -m 4G,maxmem=511G -monitor stdio

  Region             compact-highmem=off         compact-highmem=on
  ----------------------------------------------------------------
  MEM                [1GB         512GB]        [1GB         512GB]
  HIGH_GIC_REDISTS2  [512GB       512GB+64MB]   [disabled]
  HIGH_PCIE_ECAM     [512GB+256MB 512GB+512MB]  [disabled]
  HIGH_PCIE_MMIO     [disabled]                 [512GB       1TB]

In order to keep backwords compatibility, we need to disable the
optimization on machine, which is virt-7.1 or ealier than it. It
means the optimization is enabled by default from virt-7.2. Besides,
'compact-highmem' property is added so that the optimization can be
explicitly enabled or disabled on all machine types by users.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
Message-id: 20221029224307.138822-7-gshan@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2022-12-15 11:18:19 +00:00
..
_templates docs: Add QEMU version information to HTML footer 2021-07-18 10:59:47 +01:00
about watchdog: remove -watchdog option 2022-09-29 11:40:28 +02:00
config docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
devel qapi: Start to elide redundant has_FOO in generated C 2022-12-13 18:31:37 +01:00
interop docs: add firmware feature flags 2022-10-12 11:02:44 +02:00
specs pci-ids: drop list of modern virtio devices 2022-10-12 12:01:11 +02:00
sphinx docs/sphinx: fix compatibility with sphinx < 1.8 2022-01-05 11:10:13 +01:00
sphinx-static docs/sphinx: add 's' keyboard binding to focus search 2021-11-08 12:27:23 +04:00
spin docs: create config/, devel/ and spin/ subdirectories 2017-06-07 18:22:03 +02:00
system hw/arm/virt: Add 'compact-highmem' property 2022-12-15 11:18:19 +00:00
tools Fix some typos in documentation and comments 2022-11-05 20:35:45 +01:00
user linux-user: Remove the deprecated ppc64abi32 target 2022-02-09 13:29:38 +00:00
COLO-FT.txt docs: Use double quotes instead of single quotes for COLO 2021-11-22 15:02:38 +01:00
block-replication.txt docs/block-replication.txt: Fix replication top-id command demo 2021-12-17 11:35:00 +01:00
bypass-iommu.txt docs: Add documentation for iommu bypass 2021-07-16 11:10:45 -04:00
colo-proxy.txt docs: update to show preferred boolean syntax for -chardev 2021-02-25 14:14:33 +01:00
conf.py sphinx: change default language to 'en' 2022-06-27 10:39:03 +01:00
defs.rst.inc docs: Fix typo in the default name of the qemu-system-x86_64 binary 2021-04-01 14:28:39 +02:00
igd-assign.txt vfio/pci: Add IGD documentation 2016-05-26 11:12:05 -06:00
image-fuzzer.txt docs: Render binary names as monospaced text 2021-11-22 15:02:38 +01:00
index.rst docs: standardize book titles to === with overline 2021-09-13 13:56:26 +02:00
memory-hotplug.txt docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
meson.build meson, configure: move --with-pkgversion, CONFIG_STAMP to meson 2022-05-07 07:46:58 +02:00
multi-thread-compression.txt Replace '-enable-kvm' with '-accel kvm' in docs and help texts 2018-06-28 19:05:32 +02:00
multiseat.txt docs: Spell QEMU all caps 2021-11-19 10:16:58 +01:00
nvdimm.txt docs/nvdimm: Update nvdimm option value in machine example 2021-09-27 10:57:21 +02:00
pci_expander_bridge.txt pxb: cleanup 2016-03-11 16:59:12 +02:00
pcie.txt docs: pcie: Spell out machine type needs for PCIe features 2018-03-01 16:25:37 +02:00
pcie_pci_bridge.txt docs: add slot when adding new PCIe root port 2021-07-03 03:12:35 -04:00
pcie_sriov.txt docs: Replace Qemu -> QEMU 2022-04-26 12:38:44 +02:00
pvrdma.txt docs: Fix broken links 2020-09-01 09:31:33 +02:00
qcow2-cache.txt qcow2: Document the Extended L2 Entries feature 2020-08-25 08:33:20 +02:00
qdev-device-use.txt hw/ide: remove 'ide-drive' device 2021-03-18 09:22:55 +00:00
qemu-option-trace.rst.inc qemu-option-trace.rst.inc: Don't use option:: markup 2020-11-02 16:52:18 +00:00
qemupciserial.inf docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
rdma.txt migrate: remove QMP/HMP commands for speed, downtime and cache size 2021-03-18 09:22:55 +00:00
spice-port-fqdn.txt docs: add spice-port-fqdn.txt 2012-12-17 14:01:41 +01:00
throttle.txt docs: Drop deprecated 'props' from object-add 2021-11-22 15:02:38 +01:00
u2f.txt docs: Spell QEMU all caps 2021-11-19 10:16:58 +01:00
xbzrle.txt migrate: remove QMP/HMP commands for speed, downtime and cache size 2021-03-18 09:22:55 +00:00
xen-save-devices-state.txt Fix up dangling references to qmp-commands.* in comment and doc 2018-03-02 13:48:26 -06:00