Patchwork [V2] Drop check_rxov, always treat RX ring with RHD == RDT as empty

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Submitter Dmitry Fleytman
Date Oct. 18, 2012, 6:59 p.m.
Message ID <1350586751-19050-2-git-send-email-dmitry@daynix.com>
Download mbox | patch
Permalink /patch/192418/
State New
Headers show

Comments

Dmitry Fleytman - Oct. 18, 2012, 6:59 p.m.
Real HW always treats RX ring with RDH == RDT as empty.
Emulation is supposed to behave the same.

Reported-by: Chris Webb <chris.webb@elastichosts.com>
Reported-by: Richard Davies <richard.davies@elastichosts.com>
Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
---
 hw/e1000.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)
Peter Maydell - Oct. 18, 2012, 7:20 p.m.
On 18 October 2012 19:59, Dmitry Fleytman <dmitry@daynix.com> wrote:
> Real HW always treats RX ring with RDH == RDT as empty.
> Emulation is supposed to behave the same.

If you need to do a v3 of this patch for some reason, it would
be nice to amend the summary line so it started "e1000: " so
people scanning git logs know which device is affected.

Also your commit message body says "RDH" but the subject
says "RHD"...

thanks
-- PMM
Dmitry Fleytman - Oct. 18, 2012, 8:59 p.m.
Thanks, Peter

I'll resend the patch.

Sent from my iPad

On Oct 18, 2012, at 9:20 PM, Peter Maydell <peter.maydell@linaro.org> wrote:

> On 18 October 2012 19:59, Dmitry Fleytman <dmitry@daynix.com> wrote:
>> Real HW always treats RX ring with RDH == RDT as empty.
>> Emulation is supposed to behave the same.
> 
> If you need to do a v3 of this patch for some reason, it would
> be nice to amend the summary line so it started "e1000: " so
> people scanning git logs know which device is affected.
> 
> Also your commit message body says "RDH" but the subject
> says "RHD"...
> 
> thanks
> -- PMM

Patch

diff --git a/hw/e1000.c b/hw/e1000.c
index 63fee10..ab39d47 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -92,7 +92,6 @@  typedef struct E1000State_st {
 
     uint32_t rxbuf_size;
     uint32_t rxbuf_min_shift;
-    int check_rxov;
     struct e1000_tx {
         unsigned char header[256];
         unsigned char vlan_header[4];
@@ -741,11 +740,11 @@  static bool e1000_has_rxbufs(E1000State *s, size_t total_size)
     int bufs;
     /* Fast-path short packets */
     if (total_size <= s->rxbuf_size) {
-        return s->mac_reg[RDH] != s->mac_reg[RDT] || !s->check_rxov;
+        return s->mac_reg[RDH] != s->mac_reg[RDT];
     }
     if (s->mac_reg[RDH] < s->mac_reg[RDT]) {
         bufs = s->mac_reg[RDT] - s->mac_reg[RDH];
-    } else if (s->mac_reg[RDH] > s->mac_reg[RDT] || !s->check_rxov) {
+    } else if (s->mac_reg[RDH] > s->mac_reg[RDT]) {
         bufs = s->mac_reg[RDLEN] /  sizeof(struct e1000_rx_desc) +
             s->mac_reg[RDT] - s->mac_reg[RDH];
     } else {
@@ -848,7 +847,6 @@  e1000_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 
         if (++s->mac_reg[RDH] * sizeof(desc) >= s->mac_reg[RDLEN])
             s->mac_reg[RDH] = 0;
-        s->check_rxov = 1;
         /* see comment in start_xmit; same here */
         if (s->mac_reg[RDH] == rdh_start) {
             DBGOUT(RXERR, "RDH wraparound @%x, RDT %x, RDLEN %x\n",
@@ -925,7 +923,6 @@  mac_writereg(E1000State *s, int index, uint32_t val)
 static void
 set_rdt(E1000State *s, int index, uint32_t val)
 {
-    s->check_rxov = 0;
     s->mac_reg[index] = val & 0xffff;
     if (e1000_has_rxbufs(s, 1)) {
         qemu_flush_queued_packets(&s->nic->nc);