From c66cd34696f1f7f04b367a5f8b4d79802cddafb4 Mon Sep 17 00:00:00 2001

From: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>

Date: Thu, 8 May 2014 10:58:42 +0200

Subject: [PATCH 07/31] XBZRLE: Fix one XBZRLE corruption issues

RH-Author: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>

Message-id: <1399546722-6350-5-git-send-email-dgilbert@redhat.com>

Patchwork-id: 58744

O-Subject: [RHEL7.1/RHEL7.0.z qemu-kvm PATCH 4/4] XBZRLE: Fix one XBZRLE corruption issues

Bugzilla: 1066338

RH-Acked-by: Juan Quintela <quintela@redhat.com>

RH-Acked-by: Markus Armbruster <armbru@redhat.com>

RH-Acked-by: Amit Shah <amit.shah@redhat.com>

From: ChenLiang <chenliang88@huawei.com>

The page may not be inserted into cache after executing save_xbzrle_page.

In case of failure to insert, the original page should be sent rather

than the page in the cache.

Signed-off-by: ChenLiang <chenliang88@huawei.com>

Signed-off-by: Gonglei <arei.gonglei@huawei.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

Signed-off-by: Juan Quintela <quintela@redhat.com>

(cherry picked from commit 1534ee93cc6be992c05577886b24bd44c37ecff6)

---

 arch_init.c | 25 +++++++++++++------------

 1 file changed, 13 insertions(+), 12 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 arch_init.c |   25 +++++++++++++------------

 1 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch_init.c b/arch_init.c

index 80e48f2..22f7def 100644

--- a/arch_init.c

+++ b/arch_init.c

@@ -341,7 +341,7 @@ static void xbzrle_cache_zero_page(ram_addr_t current_addr)

 #define ENCODING_FLAG_XBZRLE 0x1

-static int save_xbzrle_page(QEMUFile *f, uint8_t *current_data,

+static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data,

                             ram_addr_t current_addr, RAMBlock *block,

                             ram_addr_t offset, int cont, bool last_stage)

 {

@@ -349,19 +349,23 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t *current_data,

     uint8_t *prev_cached_page;

     if (!cache_is_cached(XBZRLE.cache, current_addr)) {

+        acct_info.xbzrle_cache_miss++;

         if (!last_stage) {

-            if (cache_insert(XBZRLE.cache, current_addr, current_data) == -1) {

+            if (cache_insert(XBZRLE.cache, current_addr, *current_data) == -1) {

                 return -1;

+            } else {

+                /* update *current_data when the page has been

+                   inserted into cache */

+                *current_data = get_cached_data(XBZRLE.cache, current_addr);

             }

         }

-        acct_info.xbzrle_cache_miss++;

         return -1;

     }

     prev_cached_page = get_cached_data(XBZRLE.cache, current_addr);

     /* save current buffer into memory */

-    memcpy(XBZRLE.current_buf, current_data, TARGET_PAGE_SIZE);

+    memcpy(XBZRLE.current_buf, *current_data, TARGET_PAGE_SIZE);

     /* XBZRLE encoding (if there is no overflow) */

     encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,

@@ -374,7 +378,10 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t *current_data,

         DPRINTF("Overflow\n");

         acct_info.xbzrle_overflows++;

         /* update data in the cache */

-        memcpy(prev_cached_page, current_data, TARGET_PAGE_SIZE);

+        if (!last_stage) {

+            memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE);

+            *current_data = prev_cached_page;

+        }

         return -1;

     }

@@ -599,15 +606,9 @@ static int ram_save_block(QEMUFile *f, bool last_stage)

                  */

                 xbzrle_cache_zero_page(current_addr);

             } else if (!ram_bulk_stage && migrate_use_xbzrle()) {

-                bytes_sent = save_xbzrle_page(f, p, current_addr, block,

+                bytes_sent = save_xbzrle_page(f, &p, current_addr, block,

                                               offset, cont, last_stage);

                 if (!last_stage) {

-                    /* We must send exactly what's in the xbzrle cache

-                     * even if the page wasn't xbzrle compressed, so that

-                     * it's right next time.

-                     */

-                    p = get_cached_data(XBZRLE.cache, current_addr);

-

                     /* Can't send this cached data async, since the cache page

                      * might get updated before it gets to the wire

                      */

-- 

1.7.1