A TDX module update is a multi-step process, and any step can fail. The current update flow continues to later steps after an error. Continuing after a failure can cause the TDX module to enter an unrecoverable state. But certain failures during the initial module shutdown step should simply return an error to userspace, so the update can be retried cleanly. To preserve that recoverability, one option would be to abort the update only for those failures, since they occur before any TDX module state is changed. But special-casing specific failures in specific steps would complicate the do-while() update loop for no benefit. Simply abort update on any failure, at any step. Track failures for each step, stop the update loop once a failure is observed, and do not advance the state machine to the next step. Signed-off-by: Chao Gao Reviewed-by: Xu Yilun Reviewed-by: Tony Lindgren Reviewed-by: Kai Huang Reviewed-by: Kiryl Shutsemau (Meta) Link: https://lore.kernel.org/linux-coco/aQFmOZCdw64z14cJ@google.com/ # [1] --- v9: - Avoid nested if/else by deferring failure accounting to ack_state(). - Reduce indentation of the main flow. - Convert the failed flag into a counter. This avoids a conditional update of the flag; the counter can simply accumulate failures. --- arch/x86/virt/vmx/tdx/seamldr.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c index db6c52f65995..002cdae3b1ff 100644 --- a/arch/x86/virt/vmx/tdx/seamldr.c +++ b/arch/x86/virt/vmx/tdx/seamldr.c @@ -181,6 +181,7 @@ enum module_update_state { static struct update_ctrl { enum module_update_state state; int num_ack; + int num_failed; /* * Protect update_ctrl. Raw spinlock as it will be acquired from * interrupt-disabled contexts. @@ -198,12 +199,13 @@ static void __set_target_state(struct update_ctrl *ctrl, } /* Last one to ack a state moves to the next state. */ -static void ack_state(struct update_ctrl *ctrl) +static void ack_state(struct update_ctrl *ctrl, int result) { raw_spin_lock(&ctrl->lock); + ctrl->num_failed += !!result; ctrl->num_ack++; - if (ctrl->num_ack == num_online_cpus()) + if (ctrl->num_ack == num_online_cpus() && !ctrl->num_failed) __set_target_state(ctrl, ctrl->state + 1); raw_spin_unlock(&ctrl->lock); @@ -213,6 +215,7 @@ static void init_state(struct update_ctrl *ctrl) { raw_spin_lock_init(&ctrl->lock); __set_target_state(ctrl, MODULE_UPDATE_START + 1); + ctrl->num_failed = 0; } /* @@ -239,8 +242,8 @@ static int do_seamldr_install_module(void *seamldr_params) break; } - ack_state(&update_ctrl); - } while (curstate != MODULE_UPDATE_DONE); + ack_state(&update_ctrl, ret); + } while (curstate != MODULE_UPDATE_DONE && !READ_ONCE(update_ctrl.num_failed)); return ret; } -- 2.52.0