Using readl() to read the magic value and then memcmp() to check it fails on BE, as bytes will be the other way around (by virtue of the registers to follow the endianess of the guest).
Fix it by encoding the magic as an integer instead of a string. Cc: Rusty Russell <[email protected]> Cc: Michael S. Tsirkin <[email protected]> Cc: Pawel Moll <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> --- So I'm not completely sure this is the right fix, and I can imagine other ways to cure the problem: - Reading the MAGIC register byte by byte. Is that allowed? The spec only says it is 32bit wide. - Using __raw_readl() instead. Is that a generic enough API? drivers/virtio/virtio_mmio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 31f966f..3811e94 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -470,7 +470,7 @@ static int virtio_mmio_probe(struct platform_device *pdev) /* Check magic value */ magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); - if (memcmp(&magic, "virt", 4) != 0) { + if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) { dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); return -ENODEV; } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
