Merge tag 'pull-migration-20220720c' of https://gitlab.com/dagrh/qemu into staging

Migration pull 2022-07-20

This replaces yesterdays pull and:
  a) Fixes some test build errors without TLS
  b) Reenabled the zlib acceleration on s390
     now that we have Ilya's fix

  Hyman's dirty page rate limit set
  Ilya's fix for zlib vs migration
  Peter's postcopy-preempt
  Cleanup from Dan
  zero-copy tidy ups from Leo
  multifd doc fix from Juan
  Revert disable of zlib acceleration on s390x

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

# gpg: Signature made Wed 20 Jul 2022 12:18:56 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* tag 'pull-migration-20220720c' of https://gitlab.com/dagrh/qemu: (30 commits)
  Revert "gitlab: disable accelerated zlib for s390x"
  migration: Avoid false-positive on non-supported scenarios for zero-copy-send
  multifd: Document the locking of MultiFD{Send/Recv}Params
  migration/multifd: Report to user when zerocopy not working
  Add dirty-sync-missed-zero-copy migration stat
  QIOChannelSocket: Fix zero-copy flush returning code 1 when nothing sent
  migration: remove unreachable code after reading data
  tests: Add postcopy preempt tests
  tests: Add postcopy tls recovery migration test
  tests: Add postcopy tls migration test
  tests: Move MigrateCommon upper
  migration: Respect postcopy request order in preemption mode
  migration: Enable TLS for preempt channel
  migration: Export tls-[creds|hostname|authz] params to cmdline too
  migration: Add helpers to detect TLS capability
  migration: Add property x-postcopy-preempt-break-huge
  migration: Create the postcopy preempt channel asynchronously
  migration: Postcopy recover with preempt enabled
  migration: Postcopy preemption enablement
  migration: Postcopy preemption preparation on channel creation
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 41 insertions, 25 deletions

diff --git a/migration/multifd.h b/migration/multifd.h
index 4d8d89e..519f498 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -65,7 +65,9 @@ typedef struct {
 } MultiFDPages_t;
 
 typedef struct {
-    /* this fields are not changed once the thread is created */
+    /* Fields are only written at creating/deletion time */
+    /* No lock required for them, they are read only */
+
     /* channel number */
     uint8_t id;
     /* channel thread name */
@@ -74,39 +76,47 @@ typedef struct {
     QemuThread thread;
     /* communication channel */
     QIOChannel *c;
+    /* is the yank function registered */
+    bool registered_yank;
+    /* packet allocated len */
+    uint32_t packet_len;
+    /* multifd flags for sending ram */
+    int write_flags;
+
     /* sem where to wait for more work */
     QemuSemaphore sem;
+    /* syncs main thread and channels */
+    QemuSemaphore sem_sync;
+
     /* this mutex protects the following parameters */
     QemuMutex mutex;
     /* is this channel thread running */
     bool running;
     /* should this thread finish */
     bool quit;
-    /* is the yank function registered */
-    bool registered_yank;
+    /* multifd flags for each packet */
+    uint32_t flags;
+    /* global number of generated multifd packets */
+    uint64_t packet_num;
     /* thread has work to do */
     int pending_job;
-    /* array of pages to sent */
+    /* array of pages to sent.
+     * The owner of 'pages' depends of 'pending_job' value:
+     * pending_job == 0 -> migration_thread can use it.
+     * pending_job != 0 -> multifd_channel can use it.
+     */
     MultiFDPages_t *pages;
-    /* packet allocated len */
-    uint32_t packet_len;
+
+    /* thread local variables. No locking required */
+
     /* pointer to the packet */
     MultiFDPacket_t *packet;
-    /* multifd flags for sending ram */
-    int write_flags;
-    /* multifd flags for each packet */
-    uint32_t flags;
     /* size of the next packet that contains pages */
     uint32_t next_packet_size;
-    /* global number of generated multifd packets */
-    uint64_t packet_num;
-    /* thread local variables */
     /* packets sent through this channel */
     uint64_t num_packets;
     /* non zero pages sent through this channel */
     uint64_t total_normal_pages;
-    /* syncs main thread and channels */
-    QemuSemaphore sem_sync;
     /* buffers to send */
     struct iovec *iov;
     /* number of iovs used */
@@ -120,7 +130,9 @@ typedef struct {
 }  MultiFDSendParams;
 
 typedef struct {
-    /* this fields are not changed once the thread is created */
+    /* Fields are only written at creating/deletion time */
+    /* No lock required for them, they are read only */
+
     /* channel number */
     uint8_t id;
     /* channel thread name */
@@ -129,31 +141,35 @@ typedef struct {
     QemuThread thread;
     /* communication channel */
     QIOChannel *c;
+    /* packet allocated len */
+    uint32_t packet_len;
+
+    /* syncs main thread and channels */
+    QemuSemaphore sem_sync;
+
     /* this mutex protects the following parameters */
     QemuMutex mutex;
     /* is this channel thread running */
     bool running;
     /* should this thread finish */
     bool quit;
-    /* ramblock host address */
-    uint8_t *host;
-    /* packet allocated len */
-    uint32_t packet_len;
-    /* pointer to the packet */
-    MultiFDPacket_t *packet;
     /* multifd flags for each packet */
     uint32_t flags;
     /* global number of generated multifd packets */
     uint64_t packet_num;
-    /* thread local variables */
+
+    /* thread local variables. No locking required */
+
+    /* pointer to the packet */
+    MultiFDPacket_t *packet;
     /* size of the next packet that contains pages */
     uint32_t next_packet_size;
     /* packets sent through this channel */
     uint64_t num_packets;
+    /* ramblock host address */
+    uint8_t *host;
     /* non zero pages recv through this channel */
     uint64_t total_normal_pages;
-    /* syncs main thread and channels */
-    QemuSemaphore sem_sync;
     /* buffers to recv */
     struct iovec *iov;
     /* Pages that are not zero */