Re: [RFC PATCH 09/15] x86/virt/tdx: Add interface to generate a Quote

[Adrian Hunter]

On 22/05/2026 06:41, Xu Yilun wrote:
> From: Peter Fang <peter.fang@xxxxxxxxx>
> 
> Use the TDX Quoting extension's TDH.QUOTE.GET SEAMCALL to generate a
> Quote. Since the interface is shared across all KVM instances,
> serialize access to the SEAMCALL buffer with a mutex.

Isn't the concurrency configurable, so supporting only 1 instance
is a decision of the software implementation, not a TDX limitation?

> +static u64 tdx_quote_get(struct tdx_td *td, u64 in_data_pa, u64 in_data_len,
> +			 u64 hpa_list_pa, u64 total_len, u64 *quote_len)
> +{
> +	struct tdx_module_args args = {
> +		.rcx = tdx_tdr_pa(td),
> +		/* Don't bother specifying the quote id */

Need to explain why

> +		.rdx = QUOTE_ID_MASK & (u64)-1,
> +		.r8 = in_data_pa,
> +		.r9 = in_data_len,
> +		.r10 = hpa_list_pa,
> +		.r11 = total_len,
> +	};
> +	u64 r;
> +
> +	do {
> +		r = seamcall_ret(TDH_QUOTE_GET, &args);
> +	} while (r == TDX_INTERRUPTED_RESUMABLE);
> +
> +	*quote_len = args.rcx;
> +
> +	return r;
> +}

...

> +	r = tdx_quote_get(td, quote_data.hpa_list[0], (u64)in_data_len,
> +			  quote_data.hpa_list_pa, quote_data.buf_len, &out_len);
> +	if (r || !out_len || out_len > quote_data.buf_len)

Is r != TDX_SUCCESS more consistent

> +		goto out;