From f156919b4ebfc0cc512c0b4db37d2fa857b0df63 Mon Sep 17 00:00:00 2001 From: Teddy Astie Date: Tue, 6 Jan 2026 17:36:50 +0000 Subject: xen/virtio: Don't use grant-dma-ops when running as Dom0 [ Upstream commit dc8ea8714311e549ee93a2b0bdd5487d20bfadbf ] 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 Fixes: 61367688f1fb0 ("xen/virtio: enable grant based virtio on x86") Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Message-ID: <6698564dd2270a9f7377b78ebfb20cb425cabbe8.1767720955.git.teddy.astie@vates.tech> Signed-off-by: Sasha Levin --- 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 9784a77fa3c9..46cc47bd1dd0 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -360,7 +360,8 @@ 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; -- cgit v1.2.3