Hi Matthew, On 28/1/25 17:02, Matthew R. Ochs wrote:
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=1099511627776 Signed-off-by: Matthew R. Ochs <mo...@nvidia.com> --- docs/system/arm/virt.rst | 4 ++++ hw/arm/virt.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 49eb0355ef0c..43d47ffedd9a 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -2773,6 +2773,35 @@ static void virt_set_highmem_mmio(Object *obj, bool value, Error **errp) vms->highmem_mmio = value; }+static void virt_get_highmem_mmio_size(Object *obj, Visitor *v, const char *name,+ void *opaque, Error **errp) +{ + uint64_t size = extended_memmap[VIRT_HIGH_PCIE_MMIO].size; + + visit_type_size(v, name, &size, errp);
Since you correctly use visit_type_size(), maybe use in commit description example "highmem-mmio-size=1TB" rather than 1099511627776?
+}
