target-arm: Declare virtio-mmio as dma-coherent in dt

QEMU emulated hardware is always dma coherent with its guest. We do
annotate that correctly on the PCI host controller, but left out
virtio-mmio.

Recent kernels have started to interpret that flag rather than take
dma coherency as granted with virtio-mmio. While that is considered
a kernel bug, as it breaks previously working systems, it showed that
our dt description is incomplete.

This patch adds the respective marker that allows guest OSs to evaluate
that our virtio-mmio devices are indeed cache coherent.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Message-id: 1486644810-33181-2-git-send-email-agraf@suse.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/hw/arm/vexpress.c b/hw/arm/vexpress.c
index 58760f40ca229d4da41b4ffe9dd8c7eb0a5c4e33..e05756846e8941dda97616448caaf67d8f4a4373 100644 (file)
--- a/hw/arm/vexpress.c
+++ b/hw/arm/vexpress.c
@@ -452,6 +452,7 @@ static int add_virtio_mmio_node(void *fdt, uint32_t acells, uint32_t scells,
                                        acells, addr, scells, size);
     qemu_fdt_setprop_cells(fdt, nodename, "interrupt-parent", intc);
     qemu_fdt_setprop_cells(fdt, nodename, "interrupts", 0, irq, 1);
+    qemu_fdt_setprop(fdt, nodename, "dma-coherent", NULL, 0);
     g_free(nodename);
     if (rc) {
         return -1;

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 8eef143a5bf56b539a8b9821b9eed87aabc866ec..d20e62760092a7f9ba4f5e810dcca81326a65a91 100644 (file)
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -797,6 +797,7 @@ static void create_virtio_devices(const VirtMachineState *vms, qemu_irq *pic)
         qemu_fdt_setprop_cells(vms->fdt, nodename, "interrupts",
                                GIC_FDT_IRQ_TYPE_SPI, irq,
                                GIC_FDT_IRQ_FLAGS_EDGE_LO_HI);
+        qemu_fdt_setprop(vms->fdt, nodename, "dma-coherent", NULL, 0);
         g_free(nodename);
     }
 }