From a5ed22948873b50fcf1415d1ce15c71d61a9388d Mon Sep 17 00:00:00 2001
From: Juan Quintela <quintela@redhat.com>
Date: Fri, 19 Nov 2021 14:14:11 +0100
Subject: [PATCH] multifd: Make zlib compression method not use iovs

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/multifd-zlib.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
index e85ef8824d..da6201704c 100644
--- a/migration/multifd-zlib.c
+++ b/migration/multifd-zlib.c
@@ -13,6 +13,7 @@
 #include "qemu/osdep.h"
 #include <zlib.h>
 #include "qemu/rcu.h"
+#include "exec/ramblock.h"
 #include "exec/target_page.h"
 #include "qapi/error.h"
 #include "migration.h"
@@ -98,8 +99,8 @@ static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
  */
 static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)
 {
-    struct iovec *iov = p->pages->iov;
     struct zlib_data *z = p->data;
+    size_t page_size = qemu_target_page_size();
     z_stream *zs = &z->zs;
     uint32_t out_size = 0;
     int ret;
@@ -113,8 +114,8 @@ static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)
             flush = Z_SYNC_FLUSH;
         }
 
-        zs->avail_in = iov[i].iov_len;
-        zs->next_in = iov[i].iov_base;
+        zs->avail_in = page_size;
+        zs->next_in = p->pages->block->host + p->pages->offset[i];
 
         zs->avail_out = available;
         zs->next_out = z->zbuff + out_size;
@@ -235,6 +236,7 @@ static void zlib_recv_cleanup(MultiFDRecvParams *p)
 static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
 {
     struct zlib_data *z = p->data;
+    size_t page_size = qemu_target_page_size();
     z_stream *zs = &z->zs;
     uint32_t in_size = p->next_packet_size;
     /* we measure the change of total_out */
@@ -259,7 +261,6 @@ static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
     zs->next_in = z->zbuff;
 
     for (i = 0; i < p->pages->num; i++) {
-        struct iovec *iov = &p->pages->iov[i];
         int flush = Z_NO_FLUSH;
         unsigned long start = zs->total_out;
 
@@ -267,8 +268,8 @@ static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
             flush = Z_SYNC_FLUSH;
         }
 
-        zs->avail_out = iov->iov_len;
-        zs->next_out = iov->iov_base;
+        zs->avail_out = page_size;
+        zs->next_out = p->pages->block->host + p->pages->offset[i];
 
         /*
          * Welcome to inflate semantics
@@ -281,8 +282,8 @@ static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
         do {
             ret = inflate(zs, flush);
         } while (ret == Z_OK && zs->avail_in
-                             && (zs->total_out - start) < iov->iov_len);
-        if (ret == Z_OK && (zs->total_out - start) < iov->iov_len) {
+                             && (zs->total_out - start) < page_size);
+        if (ret == Z_OK && (zs->total_out - start) < page_size) {
             error_setg(errp, "multifd %d: inflate generated too few output",
                        p->id);
             return -1;