[Qemu-devel] [PATCH v6 0/6] postcopy (& 1 test) patch for 2.7

[Qemu-devel] [PATCH v6 0/6] postcopy (& 1 test) patch for 2.7

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

  This is a small set of postcopy changes, the largest of which
is an x86 test for postcopy.

Andrea's libqtest change came about from running my test under very heavy
load.

The test includes a self contained migration workload that rapidly changes
RAM in a predictable fashion allowing us to end up in postcopy mode and
also to be able to check the contents of RAM.

  Note this sometimes fails on Linux kernels 4.5 (and current 4.6) which
  have a KVM+THP bug. Use this fix:
     https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg04028.html

v6:
  Fix for postcopy test on non-linux/linux-without-userfault
      Tested on freebsd (x86-64) where v5 failed
                linux (aarch64) where v5 worked for me, but failed for Peter
                linux (x86-64)
v5:
  Swing sys/ #include's into the ifdef __linux__ on the postcopy test

v4:
  Add a patch to fail migrate-set-capability when turning on postcopy if we
  don't have the kernel support.

v3:
  Change all the test asserts to be g_assert macros (Marcel's suggestion)

v2:
  Split 'Add stats...' into two (Eric's comment)
  Test:
      Survive qmp events landing when we're expecting a response from the
      command (qmp/libqtest doesn't help in that)
      Fix a race where we'd start postcopy early

Dave


Andrea Arcangeli (1):
  tests: fix libqtest socket timeouts

Dr. David Alan Gilbert (5):
  Postcopy: Avoid 0 length discards
  Migration: Split out ram part of qmp_query_migrate
  Postcopy: Add stats on page requests
  test: Postcopy
  Postcopy: Check for support when setting the capability

 hmp.c                         |   4 +
 include/migration/migration.h |   2 +
 migration/migration.c         |  73 +++----
 migration/ram.c               |   5 +-
 qapi-schema.json              |   6 +-
 tests/Makefile.include        |   2 +
 tests/libqtest.c              |   2 +-
 tests/postcopy-test.c         | 455 ++++++++++++++++++++++++++++++++++++++++++
 8 files changed, 511 insertions(+), 38 deletions(-)
 create mode 100644 tests/postcopy-test.c

-- 
2.7.4

[Qemu-devel] [PATCH v6 1/6] Postcopy: Avoid 0 length discards

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

The discard code in migration/ram.c would send request for
zero length discards in the case where no discards were needed.
It doesn't appear to have had any bad effect.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
---
 migration/ram.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/migration/ram.c b/migration/ram.c
index 844ea46..5f929d6 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1557,7 +1557,9 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms,
             } else {
                 discard_length = zero - one;
             }
-            postcopy_discard_send_range(ms, pds, one, discard_length);
+            if (discard_length) {
+                postcopy_discard_send_range(ms, pds, one, discard_length);
+            }
             current = one + discard_length;
         } else {
             current = one;
-- 
2.7.4

[Qemu-devel] [PATCH v6 2/6] Migration: Split out ram part of qmp_query_migrate

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

The RAM section of qmp_query_migrate is reasonably complex
and repeated 3 times.  Split it out into a helper.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviwed-by: Denis V. Lunev <den@openvz.org>
---
 migration/migration.c | 57 ++++++++++++++++++++-------------------------------
 1 file changed, 22 insertions(+), 35 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 7ecbade..1954987 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -602,6 +602,25 @@ static void get_xbzrle_cache_stats(MigrationInfo *info)
     }
 }
 
+static void populate_ram_info(MigrationInfo *info, MigrationState *s)
+{
+    info->has_ram = true;
+    info->ram = g_malloc0(sizeof(*info->ram));
+    info->ram->transferred = ram_bytes_transferred();
+    info->ram->total = ram_bytes_total();
+    info->ram->duplicate = dup_mig_pages_transferred();
+    info->ram->skipped = skipped_mig_pages_transferred();
+    info->ram->normal = norm_mig_pages_transferred();
+    info->ram->normal_bytes = norm_mig_bytes_transferred();
+    info->ram->mbps = s->mbps;
+    info->ram->dirty_sync_count = s->dirty_sync_count;
+
+    if (s->state != MIGRATION_STATUS_COMPLETED) {
+        info->ram->remaining = ram_bytes_remaining();
+        info->ram->dirty_pages_rate = s->dirty_pages_rate;
+    }
+}
+
 MigrationInfo *qmp_query_migrate(Error **errp)
 {
     MigrationInfo *info = g_malloc0(sizeof(*info));
@@ -626,18 +645,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
         info->has_setup_time = true;
         info->setup_time = s->setup_time;
 
-        info->has_ram = true;
-        info->ram = g_malloc0(sizeof(*info->ram));
-        info->ram->transferred = ram_bytes_transferred();
-        info->ram->remaining = ram_bytes_remaining();
-        info->ram->total = ram_bytes_total();
-        info->ram->duplicate = dup_mig_pages_transferred();
-        info->ram->skipped = skipped_mig_pages_transferred();
-        info->ram->normal = norm_mig_pages_transferred();
-        info->ram->normal_bytes = norm_mig_bytes_transferred();
-        info->ram->dirty_pages_rate = s->dirty_pages_rate;
-        info->ram->mbps = s->mbps;
-        info->ram->dirty_sync_count = s->dirty_sync_count;
+        populate_ram_info(info, s);
 
         if (blk_mig_active()) {
             info->has_disk = true;
@@ -665,18 +673,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
         info->has_setup_time = true;
         info->setup_time = s->setup_time;
 
-        info->has_ram = true;
-        info->ram = g_malloc0(sizeof(*info->ram));
-        info->ram->transferred = ram_bytes_transferred();
-        info->ram->remaining = ram_bytes_remaining();
-        info->ram->total = ram_bytes_total();
-        info->ram->duplicate = dup_mig_pages_transferred();
-        info->ram->skipped = skipped_mig_pages_transferred();
-        info->ram->normal = norm_mig_pages_transferred();
-        info->ram->normal_bytes = norm_mig_bytes_transferred();
-        info->ram->dirty_pages_rate = s->dirty_pages_rate;
-        info->ram->mbps = s->mbps;
-        info->ram->dirty_sync_count = s->dirty_sync_count;
+        populate_ram_info(info, s);
 
         if (blk_mig_active()) {
             info->has_disk = true;
@@ -699,17 +696,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
         info->has_setup_time = true;
         info->setup_time = s->setup_time;
 
-        info->has_ram = true;
-        info->ram = g_malloc0(sizeof(*info->ram));
-        info->ram->transferred = ram_bytes_transferred();
-        info->ram->remaining = 0;
-        info->ram->total = ram_bytes_total();
-        info->ram->duplicate = dup_mig_pages_transferred();
-        info->ram->skipped = skipped_mig_pages_transferred();
-        info->ram->normal = norm_mig_pages_transferred();
-        info->ram->normal_bytes = norm_mig_bytes_transferred();
-        info->ram->mbps = s->mbps;
-        info->ram->dirty_sync_count = s->dirty_sync_count;
+        populate_ram_info(info, s);
         break;
     case MIGRATION_STATUS_FAILED:
         info->has_status = true;
-- 
2.7.4

[Qemu-devel] [PATCH v6 3/6] Postcopy: Add stats on page requests

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

On the source, add a count of page requests received from the
destination.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
---
 hmp.c                         | 4 ++++
 include/migration/migration.h | 2 ++
 migration/migration.c         | 2 ++
 migration/ram.c               | 1 +
 qapi-schema.json              | 6 +++++-
 5 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/hmp.c b/hmp.c
index a4b1d3d..4b8e987 100644
--- a/hmp.c
+++ b/hmp.c
@@ -217,6 +217,10 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
             monitor_printf(mon, "dirty pages rate: %" PRIu64 " pages\n",
                            info->ram->dirty_pages_rate);
         }
+        if (info->ram->postcopy_requests) {
+            monitor_printf(mon, "postcopy request count: %" PRIu64 "\n",
+                           info->ram->postcopy_requests);
+        }
     }
 
     if (info->has_disk) {
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 13b12b7..836c4e3 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -160,6 +160,8 @@ struct MigrationState
     int64_t xbzrle_cache_size;
     int64_t setup_time;
     int64_t dirty_sync_count;
+    /* Count of requests incoming from destination */
+    int64_t postcopy_requests;
 
     /* Flag set once the migration has been asked to enter postcopy */
     bool start_postcopy;
diff --git a/migration/migration.c b/migration/migration.c
index 1954987..7bc406a 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -614,6 +614,7 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s)
     info->ram->normal_bytes = norm_mig_bytes_transferred();
     info->ram->mbps = s->mbps;
     info->ram->dirty_sync_count = s->dirty_sync_count;
+    info->ram->postcopy_requests = s->postcopy_requests;
 
     if (s->state != MIGRATION_STATUS_COMPLETED) {
         info->ram->remaining = ram_bytes_remaining();
@@ -991,6 +992,7 @@ MigrationState *migrate_init(const MigrationParams *params)
     s->dirty_sync_count = 0;
     s->start_postcopy = false;
     s->postcopy_after_devices = false;
+    s->postcopy_requests = 0;
     s->migration_thread_running = false;
     s->last_req_rb = NULL;
     error_free(s->error);
diff --git a/migration/ram.c b/migration/ram.c
index 5f929d6..42fb8ac 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1169,6 +1169,7 @@ int ram_save_queue_pages(MigrationState *ms, const char *rbname,
 {
     RAMBlock *ramblock;
 
+    ms->postcopy_requests++;
     rcu_read_lock();
     if (!rbname) {
         /* Reuse last RAMBlock */
diff --git a/qapi-schema.json b/qapi-schema.json
index 8483bdf..4029c14 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -382,13 +382,17 @@
 #
 # @dirty-sync-count: number of times that dirty ram was synchronized (since 2.1)
 #
+# @postcopy-requests: The number of page requests received from the destination
+#        (since 2.7)
+#
 # Since: 0.14.0
 ##
 { 'struct': 'MigrationStats',
   'data': {'transferred': 'int', 'remaining': 'int', 'total': 'int' ,
            'duplicate': 'int', 'skipped': 'int', 'normal': 'int',
            'normal-bytes': 'int', 'dirty-pages-rate' : 'int',
-           'mbps' : 'number', 'dirty-sync-count' : 'int' } }
+           'mbps' : 'number', 'dirty-sync-count' : 'int',
+           'postcopy-requests' : 'int' } }
 
 ##
 # @XBZRLECacheStats
-- 
2.7.4

[Qemu-devel] [PATCH v6 4/6] test: Postcopy

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

This is a postcopy test (x86 only) that actually runs the guest
and checks the memory contents.

The test runs from an x86 boot block with the hex embedded in the test;
the source for this is:

...........

.code16
.org 0x7c00
	.file	"fill.s"
	.text
	.globl	start
	.type	start, @function
start:             # at 0x7c00 ?
        cli
        lgdt gdtdesc
        mov $1,%eax
        mov %eax,%cr0  # Protected mode enable
        data32 ljmp $8,$0x7c20

.org 0x7c20
.code32
        # A20 enable - not sure I actually need this
        inb $0x92,%al
        or  $2,%al
        outb %al, $0x92

        # set up DS for the whole of RAM (needed on KVM)
        mov $16,%eax
        mov %eax,%ds

        mov $65,%ax
        mov $0x3f8,%dx
        outb %al,%dx

        # bl keeps a counter so we limit the output speed
        mov $0, %bl
mainloop:
        # Start from 1MB
        mov $(1024*1024),%eax
innerloop:
        incb (%eax)
        add $4096,%eax
        cmp $(100*1024*1024),%eax
        jl innerloop

        inc %bl
        jnz mainloop

        mov $66,%ax
        mov $0x3f8,%dx
        outb %al,%dx

	jmp mainloop

        # GDT magic from old (GPLv2)  Grub startup.S
        .p2align        2       /* force 4-byte alignment */
gdt:
        .word   0, 0
        .byte   0, 0, 0, 0

        /* -- code segment --
         * base = 0x00000000, limit = 0xFFFFF (4 KiB Granularity), present
         * type = 32bit code execute/read, DPL = 0
         */
        .word   0xFFFF, 0
        .byte   0, 0x9A, 0xCF, 0

        /* -- data segment --
         * base = 0x00000000, limit 0xFFFFF (4 KiB Granularity), present
         * type = 32 bit data read/write, DPL = 0
         */
        .word   0xFFFF, 0
        .byte   0, 0x92, 0xCF, 0

gdtdesc:
        .word   0x27                    /* limit */
        .long   gdt                     /* addr */

/* I'm a bootable disk */
.org 0x7dfe
        .byte 0x55
        .byte 0xAA

...........

and that can be assembled by the following magic:
    as --32 -march=i486 fill.s -o fill.o
    objcopy -O binary fill.o fill.boot
    dd if=fill.boot of=bootsect bs=256 count=2 skip=124
    xxd -i bootsect

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
---
 tests/Makefile.include |   2 +
 tests/postcopy-test.c  | 455 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 457 insertions(+)
 create mode 100644 tests/postcopy-test.c

diff --git a/tests/Makefile.include b/tests/Makefile.include
index 7d63d16..6135875 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -234,6 +234,7 @@ endif
 check-qtest-i386-y += tests/test-netfilter$(EXESUF)
 check-qtest-i386-y += tests/test-filter-mirror$(EXESUF)
 check-qtest-i386-y += tests/test-filter-redirector$(EXESUF)
+check-qtest-i386-y += tests/postcopy-test$(EXESUF)
 check-qtest-x86_64-y = $(check-qtest-i386-y)
 gcov-files-i386-y += i386-softmmu/hw/timer/mc146818rtc.c
 gcov-files-x86_64-y = $(subst i386-softmmu/,x86_64-softmmu/,$(gcov-files-i386-y))
@@ -599,6 +600,7 @@ tests/usb-hcd-uhci-test$(EXESUF): tests/usb-hcd-uhci-test.o $(libqos-usb-obj-y)
 tests/usb-hcd-ehci-test$(EXESUF): tests/usb-hcd-ehci-test.o $(libqos-usb-obj-y)
 tests/usb-hcd-xhci-test$(EXESUF): tests/usb-hcd-xhci-test.o $(libqos-usb-obj-y)
 tests/pc-cpu-test$(EXESUF): tests/pc-cpu-test.o
+tests/postcopy-test$(EXESUF): tests/postcopy-test.o
 tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o qemu-char.o qemu-timer.o $(qtest-obj-y) $(test-io-obj-y)
 tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
 tests/test-qemu-opts$(EXESUF): tests/test-qemu-opts.o $(test-util-obj-y)
diff --git a/tests/postcopy-test.c b/tests/postcopy-test.c
new file mode 100644
index 0000000..9ff88ee
--- /dev/null
+++ b/tests/postcopy-test.c
@@ -0,0 +1,455 @@
+/*
+ * QTest testcase for postcopy
+ *
+ * Copyright (c) 2016 Red Hat, Inc. and/or its affiliates
+ *   based on the vhost-user-test.c that is:
+ *      Copyright (c) 2014 Virtual Open Systems Sarl.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include <glib.h>
+
+#include "libqtest.h"
+#include "qemu/option.h"
+#include "qemu/range.h"
+#include "sysemu/char.h"
+#include "sysemu/sysemu.h"
+
+#include <qemu/sockets.h>
+
+const unsigned start_address = 1024 * 1024;
+const unsigned end_address = 100 * 1024 * 1024;
+bool got_stop;
+
+#if defined(__linux__)
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <sys/vfs.h>
+#endif
+
+#if defined(__linux__) && defined(__NR_userfaultfd) && defined(CONFIG_EVENTFD)
+#include <sys/eventfd.h>
+#include <sys/ioctl.h>
+#include <linux/userfaultfd.h>
+
+static bool ufd_version_check(void)
+{
+    struct uffdio_api api_struct;
+    uint64_t ioctl_mask;
+
+    int ufd = ufd = syscall(__NR_userfaultfd, O_CLOEXEC);
+
+    if (ufd == -1) {
+        g_test_message("Skipping test: userfaultfd not available");
+        return false;
+    }
+
+    api_struct.api = UFFD_API;
+    api_struct.features = 0;
+    if (ioctl(ufd, UFFDIO_API, &api_struct)) {
+        g_test_message("Skipping test: UFFDIO_API failed");
+        return false;
+    }
+
+    ioctl_mask = (__u64)1 << _UFFDIO_REGISTER |
+                 (__u64)1 << _UFFDIO_UNREGISTER;
+    if ((api_struct.ioctls & ioctl_mask) != ioctl_mask) {
+        g_test_message("Skipping test: Missing userfault feature");
+        return false;
+    }
+
+    return true;
+}
+
+#else
+static bool ufd_version_check(void)
+{
+    g_test_message("Skipping test: Userfault not available (builtdtime)");
+    return false;
+}
+
+#endif
+
+static const char *tmpfs;
+
+/* A simple PC boot sector that modifies memory (1-100MB) quickly
+ * outputing a 'B' every so often if it's still running.
+ */
+unsigned char bootsect[] = {
+  0xfa, 0x0f, 0x01, 0x16, 0x74, 0x7c, 0x66, 0xb8, 0x01, 0x00, 0x00, 0x00,
+  0x0f, 0x22, 0xc0, 0x66, 0xea, 0x20, 0x7c, 0x00, 0x00, 0x08, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe4, 0x92, 0x0c, 0x02,
+  0xe6, 0x92, 0xb8, 0x10, 0x00, 0x00, 0x00, 0x8e, 0xd8, 0x66, 0xb8, 0x41,
+  0x00, 0x66, 0xba, 0xf8, 0x03, 0xee, 0xb3, 0x00, 0xb8, 0x00, 0x00, 0x10,
+  0x00, 0xfe, 0x00, 0x05, 0x00, 0x10, 0x00, 0x00, 0x3d, 0x00, 0x00, 0x40,
+  0x06, 0x7c, 0xf2, 0xfe, 0xc3, 0x75, 0xe9, 0x66, 0xb8, 0x42, 0x00, 0x66,
+  0xba, 0xf8, 0x03, 0xee, 0xeb, 0xde, 0x66, 0x90, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00,
+  0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00, 0x27, 0x00, 0x5c, 0x7c,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xaa
+};
+
+/*
+ * Wait for some output in the serial output file,
+ * we get an 'A' followed by an endless string of 'B's
+ * but on the destination we won't have the A.
+ */
+static void wait_for_serial(const char *side)
+{
+    char *serialpath = g_strdup_printf("%s/%s", tmpfs, side);
+    FILE *serialfile = fopen(serialpath, "r");
+
+    do {
+        int readvalue = fgetc(serialfile);
+
+        switch (readvalue) {
+        case 'A':
+            /* Fine */
+            break;
+
+        case 'B':
+            /* It's alive! */
+            fclose(serialfile);
+            g_free(serialpath);
+            return;
+
+        case EOF:
+            fseek(serialfile, 0, SEEK_SET);
+            usleep(1000);
+            break;
+
+        default:
+            fprintf(stderr, "Unexpected %d on %s serial\n", readvalue, side);
+            g_assert_not_reached();
+        }
+    } while (true);
+}
+
+/*
+ * Events can get in the way of responses we are actually waiting for.
+ */
+static QDict *return_or_event(QDict *response)
+{
+    const char *event_string;
+    if (!qdict_haskey(response, "event")) {
+        return response;
+    }
+
+    /* OK, it was an event */
+    event_string = qdict_get_str(response, "event");
+    if (!strcmp(event_string, "STOP")) {
+        got_stop = true;
+    }
+    QDECREF(response);
+    return return_or_event(qtest_qmp_receive(global_qtest));
+}
+
+
+/*
+ * It's tricky to use qemu's migration event capability with qtest,
+ * events suddenly appearing confuse the qmp()/hmp() responses.
+ * so wait for a couple of passes to have happened before
+ * going postcopy.
+ */
+
+static uint64_t get_migration_pass(void)
+{
+    QDict *rsp, *rsp_return, *rsp_ram;
+    uint64_t result;
+
+    rsp = return_or_event(qmp("{ 'execute': 'query-migrate' }"));
+    rsp_return = qdict_get_qdict(rsp, "return");
+    if (!qdict_haskey(rsp_return, "ram")) {
+        /* Still in setup */
+        result = 0;
+    } else {
+        rsp_ram = qdict_get_qdict(rsp_return, "ram");
+        result = qdict_get_try_int(rsp_ram, "dirty-sync-count", 0);
+        QDECREF(rsp);
+    }
+    return result;
+}
+
+static void wait_for_migration_complete(void)
+{
+    QDict *rsp, *rsp_return;
+    bool completed;
+
+    do {
+        const char *status;
+
+        rsp = return_or_event(qmp("{ 'execute': 'query-migrate' }"));
+        rsp_return = qdict_get_qdict(rsp, "return");
+        status = qdict_get_str(rsp_return, "status");
+        completed = strcmp(status, "completed") == 0;
+        g_assert_cmpstr(status, !=,  "failed");
+        QDECREF(rsp);
+        usleep(1000 * 100);
+    } while (!completed);
+}
+
+static void wait_for_migration_pass(void)
+{
+    uint64_t initial_pass = get_migration_pass();
+    uint64_t pass;
+
+    /* Wait for the 1st sync */
+    do {
+        initial_pass = get_migration_pass();
+        if (got_stop || initial_pass) {
+            break;
+        }
+        usleep(1000 * 100);
+    } while (true);
+
+    do {
+        usleep(1000 * 100);
+        pass = get_migration_pass();
+    } while (pass == initial_pass && !got_stop);
+}
+
+static void check_guests_ram(void)
+{
+    /* Our ASM test will have been incrementing one byte from each page from
+     * 1MB to <100MB in order.
+     * This gives us a constraint that any page's byte should be equal or less
+     * than the previous pages byte (mod 256); and they should all be equal
+     * except for one transition at the point where we meet the incrementer.
+     * (We're running this with the guest stopped).
+     */
+    unsigned address;
+    uint8_t first_byte;
+    uint8_t last_byte;
+    bool hit_edge = false;
+    bool bad = false;
+
+    qtest_memread(global_qtest, start_address, &first_byte, 1);
+    last_byte = first_byte;
+
+    for (address = start_address + 4096; address < end_address; address += 4096)
+    {
+        uint8_t b;
+        qtest_memread(global_qtest, address, &b, 1);
+        if (b != last_byte) {
+            if (((b + 1) % 256) == last_byte && !hit_edge) {
+                /* This is OK, the guest stopped at the point of
+                 * incrementing the previous page but didn't get
+                 * to us yet.
+                 */
+                hit_edge = true;
+            } else {
+                fprintf(stderr, "Memory content inconsistency at %x"
+                                " first_byte = %x last_byte = %x current = %x"
+                                " hit_edge = %x\n",
+                                address, first_byte, last_byte, b, hit_edge);
+                bad = true;
+            }
+        }
+        last_byte = b;
+    }
+    g_assert_false(bad);
+}
+
+static void cleanup(const char *filename)
+{
+    char *path = g_strdup_printf("%s/%s", tmpfs, filename);
+
+    unlink(path);
+}
+
+static void test_migrate(void)
+{
+    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
+    QTestState *global = global_qtest, *from, *to;
+    unsigned char dest_byte_a, dest_byte_b, dest_byte_c, dest_byte_d;
+    gchar *cmd;
+    QDict *rsp;
+
+    char *bootpath = g_strdup_printf("%s/bootsect", tmpfs);
+    FILE *bootfile = fopen(bootpath, "wb");
+
+    got_stop = false;
+    g_assert_cmpint(fwrite(bootsect, 512, 1, bootfile), ==, 1);
+    fclose(bootfile);
+
+    cmd = g_strdup_printf("-machine accel=kvm:tcg -m 150M"
+                          " -name pcsource,debug-threads=on"
+                          " -serial file:%s/src_serial"
+                          " -drive file=%s,format=raw",
+                          tmpfs, bootpath);
+    from = qtest_start(cmd);
+    g_free(cmd);
+
+    cmd = g_strdup_printf("-machine accel=kvm:tcg -m 150M"
+                          " -name pcdest,debug-threads=on"
+                          " -serial file:%s/dest_serial"
+                          " -drive file=%s,format=raw"
+                          " -incoming %s",
+                          tmpfs, bootpath, uri);
+    to = qtest_init(cmd);
+    g_free(cmd);
+
+    global_qtest = from;
+    rsp = qmp("{ 'execute': 'migrate-set-capabilities',"
+                  "'arguments': { "
+                      "'capabilities': [ {"
+                          "'capability': 'postcopy-ram',"
+                          "'state': true } ] } }");
+    g_assert(qdict_haskey(rsp, "return"));
+    QDECREF(rsp);
+
+    global_qtest = to;
+    rsp = qmp("{ 'execute': 'migrate-set-capabilities',"
+                  "'arguments': { "
+                      "'capabilities': [ {"
+                          "'capability': 'postcopy-ram',"
+                          "'state': true } ] } }");
+    g_assert(qdict_haskey(rsp, "return"));
+    QDECREF(rsp);
+
+    /* We want to pick a speed slow enough that the test completes
+     * quickly, but that it doesn't complete precopy even on a slow
+     * machine, so also set the downtime.
+     */
+    global_qtest = from;
+    rsp = qmp("{ 'execute': 'migrate_set_speed',"
+              "'arguments': { 'value': 100000000 } }");
+    g_assert(qdict_haskey(rsp, "return"));
+    QDECREF(rsp);
+
+    /* 1ms downtime - it should never finish precopy */
+    rsp = qmp("{ 'execute': 'migrate_set_downtime',"
+              "'arguments': { 'value': 0.001 } }");
+    g_assert(qdict_haskey(rsp, "return"));
+    QDECREF(rsp);
+
+
+    /* Wait for the first serial output from the source */
+    wait_for_serial("src_serial");
+
+    cmd = g_strdup_printf("{ 'execute': 'migrate',"
+                          "'arguments': { 'uri': '%s' } }",
+                          uri);
+    rsp = qmp(cmd);
+    g_free(cmd);
+    g_assert(qdict_haskey(rsp, "return"));
+    QDECREF(rsp);
+
+    wait_for_migration_pass();
+
+    rsp = return_or_event(qmp("{ 'execute': 'migrate-start-postcopy' }"));
+    g_assert(qdict_haskey(rsp, "return"));
+    QDECREF(rsp);
+
+    if (!got_stop) {
+        qmp_eventwait("STOP");
+    }
+
+    global_qtest = to;
+    qmp_eventwait("RESUME");
+
+    wait_for_serial("dest_serial");
+    global_qtest = from;
+    wait_for_migration_complete();
+
+    qtest_quit(from);
+
+    global_qtest = to;
+
+    qtest_memread(to, start_address, &dest_byte_a, 1);
+
+    /* Destination still running, wait for a byte to change */
+    do {
+        qtest_memread(to, start_address, &dest_byte_b, 1);
+        usleep(10 * 1000);
+    } while (dest_byte_a == dest_byte_b);
+
+    qmp("{ 'execute' : 'stop'}");
+    /* With it stopped, check nothing changes */
+    qtest_memread(to, start_address, &dest_byte_c, 1);
+    sleep(1);
+    qtest_memread(to, start_address, &dest_byte_d, 1);
+    g_assert_cmpint(dest_byte_c, ==, dest_byte_d);
+
+    check_guests_ram();
+
+    qtest_quit(to);
+    g_free(uri);
+
+    global_qtest = global;
+
+    cleanup("bootsect");
+    cleanup("migsocket");
+    cleanup("src_serial");
+    cleanup("dest_serial");
+}
+
+int main(int argc, char **argv)
+{
+    char template[] = "/tmp/postcopy-test-XXXXXX";
+    int ret;
+
+    g_test_init(&argc, &argv, NULL);
+
+    if (!ufd_version_check()) {
+        return 0;
+    }
+
+    tmpfs = mkdtemp(template);
+    if (!tmpfs) {
+        g_test_message("mkdtemp on path (%s): %s\n", template, strerror(errno));
+    }
+    g_assert(tmpfs);
+
+    module_call_init(MODULE_INIT_QOM);
+
+    qtest_add_func("/postcopy", test_migrate);
+
+    ret = g_test_run();
+
+    g_assert_cmpint(ret, ==, 0);
+
+    ret = rmdir(tmpfs);
+    if (ret != 0) {
+        g_test_message("unable to rmdir: path (%s): %s\n",
+                       tmpfs, strerror(errno));
+    }
+
+    return ret;
+}
-- 
2.7.4

[Qemu-devel] [PATCH v6 5/6] tests: fix libqtest socket timeouts

[Dr. David Alan Gilbert (git)]

From: Andrea Arcangeli <aarcange@redhat.com>

I kept getting timeouts and unix socket accept failures under high
load, the patch fixes it.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
---
 tests/libqtest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/libqtest.c b/tests/libqtest.c
index 5c82348..eb00f13 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -26,7 +26,7 @@
 #include "qapi/qmp/qjson.h"
 
 #define MAX_IRQ 256
-#define SOCKET_TIMEOUT 5
+#define SOCKET_TIMEOUT 50
 
 QTestState *global_qtest;
 
-- 
2.7.4

[Qemu-devel] [PATCH v6 6/6] Postcopy: Check for support when setting the capability

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Knowing whether the destination host supports migration with
postcopy can be tricky.
The destination doesn't need the capability set, however
if we set it then use the opportunity to do the test and
tell the user/management layer early.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/migration.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/migration/migration.c b/migration/migration.c
index 7bc406a..253395c 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -720,6 +720,7 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
 {
     MigrationState *s = migrate_get_current();
     MigrationCapabilityStatusList *cap;
+    bool old_postcopy_cap = migrate_postcopy_ram();
 
     if (migration_is_setup_or_active(s->state)) {
         error_setg(errp, QERR_MIGRATION_ACTIVE);
@@ -742,6 +743,19 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
             s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] =
                 false;
         }
+        /* This check is reasonably expensive, so only when it's being
+         * set the first time, also it's only the destination that needs
+         * special support.
+         */
+        if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) &&
+            !postcopy_ram_supported_by_host()) {
+            /* postcopy_ram_supported_by_host will have emitted a more
+             * detailed message
+             */
+            error_report("Postcopy is not supported");
+            s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] =
+                false;
+        }
     }
 }
 
-- 
2.7.4