Merge tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator fixes from Jason Donenfeld:

 - If a hardware random number generator passes a sufficiently large
   chunk of entropy to random.c during early boot, we now skip the
   "fast_init" business and let it initialize the RNG.

   This makes CONFIG_RANDOM_TRUST_BOOTLOADER=y actually useful.

 - We already have the command line `random.trust_cpu=0/1` option for
   RDRAND, which let distros enable CONFIG_RANDOM_TRUST_CPU=y while
   placating concerns of more paranoid users.

   Now we add `random.trust_bootloader=0/1` so that distros can
   similarly enable CONFIG_RANDOM_TRUST_BOOTLOADER=y.

 - Re-add a comment that got removed by accident in the recent revert.

 - Add the spec-compliant ACPI CID for vmgenid, which Microsoft added to
   the vmgenid spec at Ard's request during earlier review.

 - Restore build-time randomness via the latent entropy plugin, which
   was lost when we transitioned to using a hash function.

* tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  random: mix build-time latent entropy into pool at init
  virt: vmgenid: recognize new CID added by Hyper-V
  random: re-add removed comment about get_random_{u32,u64} reseeding
  random: treat bootloader trust toggle the same way as cpu trust toggle
  random: skip fast_init if hwrng provides large chunk of entropy

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b7ccaa2ea867..3f1cc5e317ed 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4427,6 +4427,12 @@
 			fully seed the kernel's CRNG. Default is controlled
 			by CONFIG_RANDOM_TRUST_CPU.
 
+	random.trust_bootloader={on,off}
+			[KNL] Enable or disable trusting the use of a
+			seed passed by the bootloader (if available) to
+			fully seed the kernel's CRNG. Default is controlled
+			by CONFIG_RANDOM_TRUST_BOOTLOADER.
+
 	randomize_kstack_offset=
 			[KNL] Enable or disable kernel stack offset
 			randomization, which provides roughly 5 bits of