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authorMatthew R. Ochs <mochs@nvidia.com>2025-02-21 06:54:19 -0800
committerPeter Maydell <peter.maydell@linaro.org>2025-02-24 15:03:42 +0000
commitf10104aeae3a17f181d5bb37b7fd7dad7fe86cba (patch)
treee931c0d56cd1335b3879af70ecebca9818f70afd /docs/system
parentab544de12787035edb7ad4994a80f9cd6a6b55d7 (diff)
downloadfocaccia-qemu-f10104aeae3a17f181d5bb37b7fd7dad7fe86cba.tar.gz
focaccia-qemu-f10104aeae3a17f181d5bb37b7fd7dad7fe86cba.zip
hw/arm/virt: Support larger highmem MMIO regions
The MMIO region size required to support virtualized environments with
large PCI BAR regions can exceed the hardcoded limit configured in QEMU.
For example, a VM with multiple NVIDIA Grace-Hopper GPUs passed through
requires more MMIO memory than the amount provided by VIRT_HIGH_PCIE_MMIO
(currently 512GB). Instead of updating VIRT_HIGH_PCIE_MMIO, introduce a
new parameter, highmem-mmio-size, that specifies the MMIO size required
to support the VM configuration.

Example usage with 1TB MMIO region size:
	-machine virt,gic-version=3,highmem-mmio-size=1T

Signed-off-by: Matthew R. Ochs <mochs@nvidia.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Message-id: 20250221145419.1281890-1-mochs@nvidia.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs/system')
-rw-r--r--docs/system/arm/virt.rst4
1 files changed, 4 insertions, 0 deletions
diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
index 0c9c2ce035..adf446c0a2 100644
--- a/docs/system/arm/virt.rst
+++ b/docs/system/arm/virt.rst
@@ -144,6 +144,10 @@ highmem-mmio
   Set ``on``/``off`` to enable/disable the high memory region for PCI MMIO.
   The default is ``on``.
 
+highmem-mmio-size
+  Set the high memory region size for PCI MMIO. Must be a power of 2 and
+  greater than or equal to the default size (512G).
+
 gic-version
   Specify the version of the Generic Interrupt Controller (GIC) to provide.
   Valid values are: