Re: [PATCH v2 11/17] x86/virt/tdx: Add interface to generate a Quote

[Peter Fang <peter.fang@intel.com>]

On Thu, Jun 18, 2026 at 08:49:40AM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] tdx_quote_generate() uses an uninterruptible mutex lock for a guest-triggered hardware operation, creating a potential host-level denial of service.
> --
> 
> > +void *tdx_quote_generate(struct tdx_td *td, void *in_data, u32 in_data_len,
> > +			 u32 *quote_len)
> > +{
> > +	struct tdx_quote_data *qdata = &tdx_quote;
> > +	void *quote_dup = NULL;
> > +	u64 r, out_len;
> > +
> > +	if (!tdx_quote_enabled())
> > +		return NULL;
> > +
> > +	mutex_lock(&tdx_quote_lock);
> 
> [Severity: High]
> Since this path can be triggered by a guest, could using an uninterruptible
> mutex_lock() here lead to a host-level denial of service?
> 
> If a guest rapidly requests quotes from multiple vCPUs, it could monopolize
> the global tdx_quote_lock. Other vCPU threads waiting for the lock would
> block in an uninterruptible sleep (D state). If an administrator attempts
> to kill the waiting VMs, the threads will not respond to fatal signals until
> they acquire the lock.
> 
> Would it be safer to use mutex_lock_killable() here to allow fatal signals
> to interrupt the wait and permit VM teardown?

This is a good idea, but I think graceful teardown can be addressed
later.

> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260618081355.3253581-1-yilun.xu@linux.intel.com?part=11
>