lkml.org 
[lkml]   [2022]   [May]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 3/3] x86/tdx: Add Quote generation support
On Sun, May 01, 2022 at 11:35:00AM -0700, Kuppuswamy Sathyanarayanan wrote:

[snip]

> +
> +static long tdx_get_quote(void __user *argp)
> +{
> + struct tdx_quote_req quote_req;
> + long ret = 0;
> + int order;
> +
> + /* Hold lock to serialize GetQuote requests */
> + mutex_lock(&quote_lock);
> +
> + reinit_completion(&req_compl);
> +
> + /* Copy GetQuote request struct from user buffer */
> + if (copy_from_user(&quote_req, argp, sizeof(struct tdx_quote_req))) {
> + ret = -EFAULT;
> + goto quote_failed;
> + }
> +
> + /* Make sure the length & timeout is valid */
> + if (!quote_req.len || !quote_req.timeout) {
> + ret = -EINVAL;
> + goto quote_failed;
> + }
> +
> + /* Get order for Quote buffer page allocation */
> + order = get_order(quote_req.len);
> +
> + /*
> + * Allocate buffer to get TD Quote from the VMM.
> + * Size needs to be 4KB aligned (which is already
> + * met in page allocation).
> + */
> + tdquote = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
> + if (!tdquote) {
> + ret = -ENOMEM;
> + goto quote_failed;
> + }
> +
> + /*
> + * Since this buffer will be shared with the VMM via GetQuote
> + * hypercall, decrypt it.
> + */
> + ret = set_memory_decrypted((unsigned long)tdquote, 1UL << order);
> + if (ret)
> + goto quote_failed;
> +
> + /* Copy TDREPORT from user buffer to kernel Quote buffer */
> + if (copy_from_user(tdquote, (void __user *)quote_req.buf, quote_req.len)) {
> + ret = -EFAULT;
> + goto quote_failed;
> + }
> +
> + /* Submit GetQuote Request */
> + ret = tdx_get_quote_hypercall(tdquote, (1ULL << order) * PAGE_SIZE);
> + if (ret) {
> + pr_err("GetQuote hypercall failed, status:%lx\n", ret);
> + ret = -EIO;
> + goto quote_failed;
> + }
> +
> + /* Wait for attestation completion */
> + ret = wait_for_completion_interruptible(&req_compl);
> + if (ret <= 0) {
> + ret = -EIO;
> + goto quote_failed;
> + }
> +
> + /* Copy output data back to user buffer */
> + if (copy_to_user((void __user *)quote_req.buf, tdquote, quote_req.len))
> + ret = -EFAULT;
> +

IIUC, ret has a positive value at this point, due to the call to
wait_for_completion_interruptible, so we need add "ret = 0;"
here, don't we?

[snip]

\
 
 \ /
  Last update: 2022-05-02 15:19    [W:0.194 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site