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| -rw-r--r-- | hw/arm/virt.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 8555615..0784ee7 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -271,6 +271,17 @@ static void create_fdt(VirtMachineState *vms) qemu_fdt_setprop_cell(fdt, "/", "#size-cells", 0x2); qemu_fdt_setprop_string(fdt, "/", "model", "linux,dummy-virt"); + /* + * For QEMU, all DMA is coherent. Advertising this in the root node + * has two benefits: + * + * - It avoids potential bugs where we forget to mark a DMA + * capable device as being dma-coherent + * - It avoids spurious warnings from the Linux kernel about + * devices which can't do DMA at all + */ + qemu_fdt_setprop(fdt, "/", "dma-coherent", NULL, 0); + /* /chosen must exist for load_dtb to fill in necessary properties later */ qemu_fdt_add_subnode(fdt, "/chosen"); if (vms->dtb_randomness) { |