On Tue, Oct 10, 2017 at 05:32:53PM +0300, Jarkko Sakkinen wrote:
> diff --git a/drivers/platform/x86/intel_sgx/sgx_page_cache.c b/drivers/platform/x86/intel_sgx/sgx_page_cache.c
> new file mode 100644
> index 000000000000..1089b563e07b
> --- /dev/null
> +++ b/drivers/platform/x86/intel_sgx/sgx_page_cache.c
>
> +/**
> + * sgx_alloc_page - allocate an EPC page
> + * @flags: allocation flags
> + *
> + * Try to grab a page from the free EPC page list. If there is a free page
> + * available, it is returned to the caller. If called with SGX_ALLOC_ATOMIC,
> + * the function will return immediately if the list is empty. Otherwise, it
> + * will swap pages up until there is a free page available. Before returning
> + * the low watermark is checked and ksgxswapd is waken up if we are below it.
> + *
> + * Return: an EPC page or a system error code
> + */
> +struct sgx_epc_page *sgx_alloc_page(unsigned int flags)
> +{
> + struct sgx_epc_page *entry;
> +
> + for ( ; ; ) {
> + entry = sgx_alloc_page_fast();
> + if (entry)
> + break;
> +
> + /* We need at minimum two pages for the #PF handler. */
> + if (atomic_read(&sgx_va_pages_cnt) >
> + (sgx_nr_total_epc_pages - 2))
> + return ERR_PTR(-ENOMEM);
> +
> + if (flags & SGX_ALLOC_ATOMIC) {
> + entry = ERR_PTR(-EBUSY);
> + break;
> + }
> +
> + if (signal_pending(current)) {
> + entry = ERR_PTR(-ERESTARTSYS);
> + break;
> + }
> +
> + sgx_swap_pages(SGX_NR_SWAP_CLUSTER_MAX);
> + schedule();
> + }
> +
> + if (sgx_nr_free_pages < sgx_nr_low_pages)
> + wake_up(&ksgxswapd_waitq);
> +
> + return entry;
> +}
> +EXPORT_SYMBOL(sgx_alloc_page);
I think it makes sense to remove the exports from sgx_page_cache.c
for the initial upstreaming given that the only consumer is the
pre-release/out-of-tree KVM module, which generally requires
recompiling the entire kernel anyways.
