[Qemu-devel] [PATCH] make e1000 use the checksuming code

[Qemu-devel] [PATCH] make e1000 use the checksuming code

[Gerd Hoffmann]

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  Hi,

This patch makes the e1000 nic driver use the checksumming code added
with the previous patch.  That one better should be reviewed by someone
knowing the e1000 better than I do.  I think I got it right though ...

cheers,
  Gerd

-- 
http://kraxel.fedorapeople.org/xenner/

[-- Attachment #2: 0005-e1000-use-common-checksumming-code.patch --]
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>From 6b61fa35c52092c6372e9d095e2131370cc151cd Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue, 29 Jul 2008 13:39:32 +0200
Subject: [PATCH 05/22] e1000: use common checksumming code.


Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/e1000.c |   20 ++++++--------------
 1 files changed, 6 insertions(+), 14 deletions(-)

diff --git a/hw/e1000.c b/hw/e1000.c
index 1a14051..d81d9be 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -279,26 +279,18 @@ flash_eerd_read(E1000State *s, int x)
            E1000_EEPROM_RW_REG_DONE | r;
 }
 
-static unsigned int
-do_cksum(uint8_t *dp, uint8_t *de)
-{
-    unsigned int bsum[2] = {0, 0}, i, sum;
-
-    for (i = 1; dp < de; bsum[i^=1] += *dp++)
-        ;
-    sum = (bsum[0] << 8) + bsum[1];
-    sum = (sum >> 16) + (sum & 0xffff);
-    return ~(sum + (sum >> 16));
-}
-
 static void
 putsum(uint8_t *data, uint32_t n, uint32_t sloc, uint32_t css, uint32_t cse)
 {
+    uint32_t sum;
+
     if (cse && cse < n)
         n = cse + 1;
-    if (sloc < n-1)
+    if (sloc < n-1) {
+        sum = net_checksum_add(n-css, data+css);
         cpu_to_be16wu((uint16_t *)(data + sloc),
-                      do_cksum(data + css, data + n));
+                      net_checksum_finish(sum));
+    }
 }
 
 static void
-- 
1.5.4.1

Re: [Qemu-devel] [PATCH] make e1000 use the checksuming code

[Anthony Liguori]

Gerd Hoffmann wrote:
>   Hi,
>
> This patch makes the e1000 nic driver use the checksumming code added
> with the previous patch.  That one better should be reviewed by someone
> knowing the e1000 better than I do.  I think I got it right though ...
>   

Applied this and the v2 of the checksumming patch.  I reviewed the 
checksumming code carefully for the e1000 and AFAICT, it's identical to 
the old behaviour.  It also tested for packet corruption and everything 
appears okay.

Thanks.

Regards,

Anthony Liguori

> cheers,
>   Gerd
>
>