[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 2/2] spapr: Fix stale HTAB during live migration (TC
From: |
Samuel Mendoza-Jonas |
Subject: |
[Qemu-devel] [PATCH 2/2] spapr: Fix stale HTAB during live migration (TCG) |
Date: |
Wed, 5 Nov 2014 17:17:01 +1100 |
If a TCG guest reboots during a running migration HTAB entries are not
marked dirty, and the destination boots with an invalid HTAB.
When a reboot occurs reset the state of HTAB migration, and explicitly
inform the destination of invalid entries.
Signed-off-by: Samuel Mendoza-Jonas <address@hidden>
---
hw/ppc/spapr.c | 59 +++++++++++++++++++++++++++++++++++---------------
include/hw/ppc/spapr.h | 1 +
2 files changed, 42 insertions(+), 18 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 1610c28..9f419e8 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -829,26 +829,30 @@ static void spapr_reset_htab(sPAPREnvironment *spapr)
shift = kvmppc_reset_htab(spapr->htab_shift);
+ pthread_mutex_lock(&spapr->htab_mutex);
if (shift > 0) {
/* Kernel handles htab, we don't need to allocate one */
spapr->htab_shift = shift;
kvmppc_kern_htab = true;
/* Tell readers to update their file descriptor */
- pthread_mutex_lock(&spapr->htab_mutex);
if (spapr->htab_fd > 0) {
spapr->htab_fd_stale = true;
}
- pthread_mutex_unlock(&spapr->htab_mutex);
} else {
if (!spapr->htab) {
/* Allocate an htab if we don't yet have one */
spapr->htab = qemu_memalign(HTAB_SIZE(spapr), HTAB_SIZE(spapr));
+ } else {
+ spapr->htab_mig_full = true;
+ spapr->htab_first_pass = true;
+ spapr->htab_save_index = 0;
}
/* And clear it */
memset(spapr->htab, 0, HTAB_SIZE(spapr));
}
+ pthread_mutex_unlock(&spapr->htab_mutex);
/* Update the RMA size if necessary */
if (spapr->vrma_adjust) {
@@ -1019,6 +1023,7 @@ static int htab_save_setup(QEMUFile *f, void *opaque)
pthread_mutex_lock(&spapr->htab_mutex);
spapr->htab_fd = kvmppc_get_htab_fd(false);
spapr->htab_fd_stale = false;
+ spapr->htab_mig_full = false;
pthread_mutex_unlock(&spapr->htab_mutex);
if (spapr->htab_fd < 0) {
fprintf(stderr, "Unable to open fd for reading hash table from
KVM: %s\n",
@@ -1034,6 +1039,7 @@ static int htab_save_setup(QEMUFile *f, void *opaque)
static void htab_save_first_pass(QEMUFile *f, sPAPREnvironment *spapr,
int64_t max_ns)
{
+ bool final = max_ns < 0;
int htabslots = HTAB_SIZE(spapr) / HASH_PTE_SIZE_64;
int index = spapr->htab_save_index;
int64_t starttime = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
@@ -1041,33 +1047,40 @@ static void htab_save_first_pass(QEMUFile *f,
sPAPREnvironment *spapr,
assert(spapr->htab_first_pass);
do {
- int chunkstart;
+ int chunkstart, invalidstart;
- /* Consume invalid HPTEs */
- while ((index < htabslots)
- && !HPTE_VALID(HPTE(spapr->htab, index))) {
+ chunkstart = index;
+ /* Consume valid HPTEs */
+ while ((index < htabslots && (index - chunkstart < USHRT_MAX))
+ && HPTE_VALID(HPTE(spapr->htab, index))) {
index++;
CLEAN_HPTE(HPTE(spapr->htab, index));
}
- /* Consume valid HPTEs */
- chunkstart = index;
- while ((index < htabslots)
- && HPTE_VALID(HPTE(spapr->htab, index))) {
+ invalidstart = index;
+ /* Consume invalid HPTEs */
+ while ((index < htabslots && (index - invalidstart < USHRT_MAX))
+ && !HPTE_VALID(HPTE(spapr->htab, index))) {
index++;
CLEAN_HPTE(HPTE(spapr->htab, index));
}
- if (index > chunkstart) {
- int n_valid = index - chunkstart;
+ /* Avoid writing an end marker (0,0,0) */
+ if (index > chunkstart
+ && !(chunkstart == invalidstart && !spapr->htab_mig_full)) {
+ int n_valid = invalidstart - chunkstart;
+ /* If a reset has occured we must explicitly overwrite the HTAB
+ * of the destination */
+ int n_invalid = spapr->htab_mig_full ? index - invalidstart : 0;
qemu_put_be32(f, chunkstart);
qemu_put_be16(f, n_valid);
- qemu_put_be16(f, 0);
+ qemu_put_be16(f, n_invalid);
qemu_put_buffer(f, HPTE(spapr->htab, chunkstart),
HASH_PTE_SIZE_64 * n_valid);
- if ((qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - starttime) > max_ns)
{
+ if ((qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - starttime) > max_ns
+ && !final) {
break;
}
}
@@ -1182,10 +1195,14 @@ static int htab_save_iterate(QEMUFile *f, void *opaque)
if (rc < 0) {
return rc;
}
- } else if (spapr->htab_first_pass) {
- htab_save_first_pass(f, spapr, MAX_ITERATION_NS);
} else {
- rc = htab_save_later_pass(f, spapr, MAX_ITERATION_NS);
+ pthread_mutex_lock(&spapr->htab_mutex);
+ if (spapr->htab_first_pass) {
+ htab_save_first_pass(f, spapr, MAX_ITERATION_NS);
+ } else {
+ rc = htab_save_later_pass(f, spapr, MAX_ITERATION_NS);
+ }
+ pthread_mutex_unlock(&spapr->htab_mutex);
}
/* End marker */
@@ -1220,7 +1237,13 @@ static int htab_save_complete(QEMUFile *f, void *opaque)
close(spapr->htab_fd);
spapr->htab_fd = -1;
} else {
- htab_save_later_pass(f, spapr, -1);
+ pthread_mutex_lock(&spapr->htab_mutex);
+ if (spapr->htab_first_pass) {
+ htab_save_first_pass(f, spapr, -1);
+ } else {
+ htab_save_later_pass(f, spapr, -1);
+ }
+ pthread_mutex_unlock(&spapr->htab_mutex);
}
/* End marker */
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 5e29bec..ee95459 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -38,6 +38,7 @@ typedef struct sPAPREnvironment {
bool htab_first_pass;
int htab_fd;
bool htab_fd_stale;
+ bool htab_mig_full;
pthread_mutex_t htab_mutex;
} sPAPREnvironment;
--
1.9.3