crypto: ccp - Avoid page allocation failure warning for SEV_GET_ID2

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2130715
Upstream Status: merged into herbert/cryptodev-2.6.git

commit 91dfd98
Author: David Rientjes <rientjes@google.com>
Date:   Fri Dec 30 14:18:46 2022 -0800

    crypto: ccp - Avoid page allocation failure warning for SEV_GET_ID2

    For SEV_GET_ID2, the user provided length does not have a specified
    limitation because the length of the ID may change in the future.  The
    kernel memory allocation, however, is implicitly limited to 4MB on x86 by
    the page allocator, otherwise the kzalloc() will fail.

    When this happens, it is best not to spam the kernel log with the warning.
    Simply fail the allocation and return ENOMEM to the user.

    Fixes: d6112ea ("crypto: ccp - introduce SEV_GET_ID2 command")
    Reported-by: Andy Nguyen <theflow@google.com>
    Reported-by: Peter Gonda <pgonda@google.com>
    Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: David Rientjes <rientjes@google.com>
    Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: Vladis Dronov <vdronov@redhat.com>

Author: nefigtut

drivers/crypto/ccp/sev-dev.c

@@ -881,7 +881,14 @@ static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp)
 	input_address = (void __user *)input.address;
 
 	if (input.address && input.length) {
-		id_blob = kzalloc(input.length, GFP_KERNEL);
+		/*
+		 * The length of the ID shouldn't be assumed by software since
+		 * it may change in the future.  The allocation size is limited
+		 * to 1 << (PAGE_SHIFT + MAX_ORDER - 1) by the page allocator.
+		 * If the allocation fails, simply return ENOMEM rather than
+		 * warning in the kernel log.
+		 */
+		id_blob = kzalloc(input.length, GFP_KERNEL | __GFP_NOWARN);
 		if (!id_blob)
 			return -ENOMEM;