On 22.09.22 16:35, Jason A. Donenfeld wrote:
On Thu, Sep 22, 2022 at 03:07:13PM +0200, David Hildenbrand wrote:
+ if (processed >= MAX_BLOCKS_PER_RUN * 128) {
+ break;
If you make this a `goto out` or similar instead of a break, then you
can
+ if (type == S390_FEAT_TYPE_KLMD && len < 128) {
change that to `if (len)`.
Thanks, I'll do this on top:
diff --git a/target/s390x/tcg/crypto_helper.c b/target/s390x/tcg/crypto_helper.c
index 67133ba33a..c1505b27a4 100644
--- a/target/s390x/tcg/crypto_helper.c
+++ b/target/s390x/tcg/crypto_helper.c
@@ -190,7 +190,7 @@ static int cpacf_sha512(CPUS390XState *env, uintptr_t ra,
uint64_t param_addr,
uint64_t w[16];
if (processed >= MAX_BLOCKS_PER_RUN * 128) {
- break;
+ goto write_ocv;
}
sha512_read_block(env, *message_reg + processed, w, ra);
@@ -198,7 +198,7 @@ static int cpacf_sha512(CPUS390XState *env, uintptr_t ra,
uint64_t param_addr,
}
/* KMLD: Process partial/empty block last. */
- if (type == S390_FEAT_TYPE_KLMD && len < 128) {
+ if (len) {
uint8_t x[128];
/* Read the remainder of the message byte-per-byte. */
@@ -237,6 +237,7 @@ static int cpacf_sha512(CPUS390XState *env, uintptr_t ra,
uint64_t param_addr,
* TODO: if writing fails halfway through (e.g., when crossing page
* boundaries), we're in trouble. We'd need something like
access_prepare().
*/
+write_ocv:
sha512_write_ocv(env, param_addr, a, ra);
*message_reg = deposit64(*message_reg, 0, message_reg_len,
*message_reg + processed);
+ /*
+ * Pad the remainder with zero and place magic value 128 after the
+ * message.
+ */
+ memset(x + len, 0, 128 - len);
+ x[len] = 128;
"magic value 128" ==> "set the top bit"
Yes, thanks. I missed that detail in the PoP. (not sure if it's documented at
all ...)
"Pad the remainder with zero and set the top bit."
Aside from these nits, this refactoring looks fine. I haven't tested
this or checked the crypto carefully, but if it passes all the Linux
test vectors, hopefully things are still fine.
Thanks. I'll resend this patch only as reply to your original one,
so Thomas can easily pick it up (or add more feedback :)).
--
Thanks,
David / dhildenb
