Dom0 inherit devices from the machine and is usually in PV mode. If we are running in a virtual that has virtio devices, these devices would be considered as using grants with Dom0 as backend, while being the said Dom0 itself, while we want to use these devices like regular PCI devices.
Fix this by preventing grant-dma-ops from being used when running as Dom0 (initial domain). We still keep the device-tree logic as-is. Signed-off-by: Teddy Astie <[email protected]> Fixes: 61367688f1fb0 ("xen/virtio: enable grant based virtio on x86") --- CC: Juergen Gross <[email protected]> CC: Stefano Stabellini <[email protected]> CC: Oleksandr Tyshchenko <[email protected]> CC: Boris Ostrovsky <[email protected]> drivers/xen/grant-dma-ops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 14077d23f2a1..c2603e700178 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -366,7 +366,8 @@ static int xen_grant_init_backend_domid(struct device *dev, if (np) { ret = xen_dt_grant_init_backend_domid(dev, np, backend_domid); of_node_put(np); - } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) { + } else if (!xen_initial_domain() && + (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain())) { dev_info(dev, "Using dom0 as backend\n"); *backend_domid = 0; ret = 0; -- 2.52.0 -- Teddy Astie | Vates XCP-ng Developer XCP-ng & Xen Orchestra - Vates solutions web: https://vates.tech
