[Qemu-devel] [PATCH 14/40] rtl8139: Do not consume the packet during overflow in standard mode.

[Michael Roth <mdroth@linux.vnet.ibm.com>]

From: Vladislav Yasevich <vyasevic@redhat.com>

When operation in standard mode, we currently return the size
of packet during buffer overflow.  This consumes the overflow
packet.  Return 0 instead so we can re-process the overflow packet
when we have room.

This fixes issues with lost/dropped fragments of large messages.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Message-id: 1441121206-6997-3-git-send-email-vyasevic@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 26c4e7ca72d970d120f0f51244bc8d37458512a0)
*removed dependency on b76f21a7
*removed context dependency on 4cbea598
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/net/rtl8139.c         |  2 +-
 tcg/aarch64/tcg-target.c | 28 +++++++++++++++++++++-------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 8a33466..cb51613 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -1159,7 +1159,7 @@ static ssize_t rtl8139_do_receive(NetClientState *nc, const uint8_t *buf, size_t
             s->IntrStatus |= RxOverflow;
             ++s->RxMissed;
             rtl8139_update_irq(s);
-            return size_;
+            return 0;
         }
 
         packet_header |= RxStatusOK;
diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
index b7ec4f5..bad8b1d 100644
--- a/tcg/aarch64/tcg-target.c
+++ b/tcg/aarch64/tcg-target.c
@@ -56,6 +56,12 @@ static const int tcg_target_call_oarg_regs[1] = {
 #define TCG_REG_TMP TCG_REG_X30
 
 #ifndef CONFIG_SOFTMMU
+/* Note that XZR cannot be encoded in the address base register slot,
+   as that actaully encodes SP.  So if we need to zero-extend the guest
+   address, via the address index register slot, we need to load even
+   a zero guest base into a register.  */
+#define USE_GUEST_BASE     (GUEST_BASE != 0 || TARGET_LONG_BITS == 32)
+
 # ifdef CONFIG_USE_GUEST_BASE
 #  define TCG_REG_GUEST_BASE TCG_REG_X28
 # else
@@ -1216,9 +1222,13 @@ static void tcg_out_qemu_ld(TCGContext *s, TCGReg data_reg, TCGReg addr_reg,
     add_qemu_ldst_label(s, true, oi, ext, data_reg, addr_reg,
                         s->code_ptr, label_ptr);
 #else /* !CONFIG_SOFTMMU */
-    tcg_out_qemu_ld_direct(s, memop, ext, data_reg,
-                           GUEST_BASE ? TCG_REG_GUEST_BASE : TCG_REG_XZR,
-                           otype, addr_reg);
+    if (USE_GUEST_BASE) {
+        tcg_out_qemu_ld_direct(s, memop, ext, data_reg,
+                               TCG_REG_GUEST_BASE, otype, addr_reg);
+    } else {
+        tcg_out_qemu_ld_direct(s, memop, ext, data_reg,
+                               addr_reg, TCG_TYPE_I64, TCG_REG_XZR);
+    }
 #endif /* CONFIG_SOFTMMU */
 }
 
@@ -1238,9 +1248,13 @@ static void tcg_out_qemu_st(TCGContext *s, TCGReg data_reg, TCGReg addr_reg,
     add_qemu_ldst_label(s, false, oi, s_bits == MO_64, data_reg, addr_reg,
                         s->code_ptr, label_ptr);
 #else /* !CONFIG_SOFTMMU */
-    tcg_out_qemu_st_direct(s, memop, data_reg,
-                           GUEST_BASE ? TCG_REG_GUEST_BASE : TCG_REG_XZR,
-                           otype, addr_reg);
+    if (USE_GUEST_BASE) {
+        tcg_out_qemu_st_direct(s, memop, data_reg,
+                               TCG_REG_GUEST_BASE, otype, addr_reg);
+    } else {
+        tcg_out_qemu_st_direct(s, memop, data_reg,
+                               addr_reg, TCG_TYPE_I64, TCG_REG_XZR);
+    }
 #endif /* CONFIG_SOFTMMU */
 }
 
@@ -1795,7 +1809,7 @@ static void tcg_target_qemu_prologue(TCGContext *s)
                   CPU_TEMP_BUF_NLONGS * sizeof(long));
 
 #if defined(CONFIG_USE_GUEST_BASE)
-    if (GUEST_BASE) {
+    if (USE_GUEST_BASE) {
         tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_GUEST_BASE, GUEST_BASE);
         tcg_regset_set_reg(s->reserved_regs, TCG_REG_GUEST_BASE);
     }
-- 
1.9.1