From 25059d5e4c5af37688797d87b2d2004ac1cddff7 Mon Sep 17 00:00:00 2001 From: Roman Kisel Date: Wed, 8 Oct 2025 16:34:10 -0700 Subject: [PATCH] Drivers: hv: Post messages through the confidential VMBus if available When the confidential VMBus is available, the guest should post messages to the paravisor. Update hv_post_message() to post messages to the paravisor rather than through GHCB or TD calls. Signed-off-by: Roman Kisel Reviewed-by: Tianyu Lan Reviewed-by: Michael Kelley Signed-off-by: Wei Liu --- drivers/hv/hv.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index d380e0df63f39..aca3a275bb1f9 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -74,7 +74,11 @@ int hv_post_message(union hv_connection_id connection_id, aligned_msg->payload_size = payload_size; memcpy((void *)aligned_msg->payload, payload, payload_size); - if (ms_hyperv.paravisor_present) { + if (ms_hyperv.paravisor_present && !vmbus_is_confidential()) { + /* + * If the VMBus isn't confidential, use the CoCo-specific + * mechanism to communicate with the hypervisor. + */ if (hv_isolation_type_tdx()) status = hv_tdx_hypercall(HVCALL_POST_MESSAGE, virt_to_phys(aligned_msg), 0); @@ -88,6 +92,11 @@ int hv_post_message(union hv_connection_id connection_id, u64 control = HVCALL_POST_MESSAGE; control |= hv_nested ? HV_HYPERCALL_NESTED : 0; + /* + * If there is no paravisor, this will go to the hypervisor. + * In the Confidential VMBus case, there is the paravisor + * to which this will trap. + */ status = hv_do_hypercall(control, aligned_msg, NULL); } -- 2.47.3