From: William Roche <william.ro...@oracle.com>
A memory page poisoned from the hypervisor level is no longer readable.
The migration of a VM will crash Qemu when it tries to read the
memory address space and stumbles on the poisoned page with a similar
stack trace:
Program terminated with signal SIGBUS, Bus error.
#0 _mm256_loadu_si256
#1 buffer_zero_avx2
#2 select_accel_fn
#3 buffer_is_zero
#4 save_zero_page
#5 ram_save_target_page_legacy
#6 ram_save_host_page
#7 ram_find_and_save_block
#8 ram_save_iterate
#9 qemu_savevm_state_iterate
#10 migration_iteration_run
#11 migration_thread
#12 qemu_thread_start
To avoid this VM crash during the migration, prevent the migration
when a known hardware poison exists on the VM.
Signed-off-by: William Roche <william.ro...@oracle.com>
---
accel/kvm/kvm-all.c | 10 ++++++++++
accel/stubs/kvm-stub.c | 5 +++++
include/sysemu/kvm.h | 6 ++++++
migration/migration.c | 7 +++++++
4 files changed, 28 insertions(+)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 49e755ec4a..a8cecd040e 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1119,6 +1119,11 @@ int kvm_vm_check_extension(KVMState *s, unsigned int
extension)
return ret;
}
+/*
+ * We track the poisoned pages to be able to:
+ * - replace them on VM reset
+ * - block a migration for a VM with a poisoned page
+ */
typedef struct HWPoisonPage {
ram_addr_t ram_addr;
QLIST_ENTRY(HWPoisonPage) list;
@@ -1152,6 +1157,11 @@ void kvm_hwpoison_page_add(ram_addr_t ram_addr)
QLIST_INSERT_HEAD(&hwpoison_page_list, page, list);
}
+bool kvm_hwpoisoned_mem(void)
+{
+ return !QLIST_EMPTY(&hwpoison_page_list);
+}
+
static uint32_t adjust_ioeventfd_endianness(uint32_t val, uint32_t size)
{
#if HOST_BIG_ENDIAN != TARGET_BIG_ENDIAN
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 1b37d9a302..ca38172884 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -124,3 +124,8 @@ uint32_t kvm_dirty_ring_size(void)
{
return 0;
}
+
+bool kvm_hwpoisoned_mem(void)
+{
+ return false;
+}
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index d614878164..fad9a7e8ff 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -538,4 +538,10 @@ bool kvm_arch_cpu_check_are_resettable(void);
bool kvm_dirty_ring_enabled(void);
uint32_t kvm_dirty_ring_size(void);
+
+/**
+ * kvm_hwpoisoned_mem - indicate if there is any hwpoisoned page
+ * reported for the VM.
+ */
+bool kvm_hwpoisoned_mem(void);
#endif
diff --git a/migration/migration.c b/migration/migration.c
index d5f705ceef..b574e66f7b 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -67,6 +67,7 @@
#include "options.h"
#include "sysemu/dirtylimit.h"
#include "qemu/sockets.h"
+#include "sysemu/kvm.h"
static NotifierList migration_state_notifiers =
NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
@@ -1906,6 +1907,12 @@ static bool migrate_prepare(MigrationState *s, bool blk,
bool blk_inc,
return false;
}
+ if (kvm_hwpoisoned_mem()) {
+ error_setg(errp, "Can't migrate this vm with hardware poisoned memory,
"
+ "please reboot the vm and try again");
+ return false;
+ }
+
if (migration_is_blocked(errp)) {
return false;
}
--
2.39.3
