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qemu-kvm/kvm-accel-kvm-refactor-dirty-ring-setup.patch
Miroslav Rezanina 1889838d24 * Tue Nov 19 2024 Miroslav Rezanina <mrezanin@redhat.com> - 9.1.0-5 
- kvm-migration-Ensure-vmstate_save-sets-errp.patch [RHEL-63051]
- kvm-kvm-replace-fprintf-with-error_report-printf-in-kvm_.patch [RHEL-57685]
- kvm-kvm-refactor-core-virtual-machine-creation-into-its-.patch [RHEL-57685]
- kvm-accel-kvm-refactor-dirty-ring-setup.patch [RHEL-57685]
- kvm-KVM-Dynamic-sized-kvm-memslots-array.patch [RHEL-57685]
- kvm-KVM-Define-KVM_MEMSLOTS_NUM_MAX_DEFAULT.patch [RHEL-57685]
- kvm-KVM-Rename-KVMMemoryListener.nr_used_slots-to-nr_slo.patch [RHEL-57685]
- kvm-KVM-Rename-KVMState-nr_slots-to-nr_slots_max.patch [RHEL-57685]
- kvm-Require-new-dtrace-package.patch [RHEL-67899]
- Resolves: RHEL-63051
  (qemu crashed after killed virtiofsd during migration)
- Resolves: RHEL-57685
  (Bad migration performance when performing vGPU VM live migration )
- Resolves: RHEL-67899
  (Failed to build qemu-kvm due to missing dtrace [rhel-10.0])
2024-11-19 02:39:29 -05:00

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From 00a2dbf483a077bb31b1c9f70cced36319d22628 Mon Sep 17 00:00:00 2001
From: Ani Sinha <anisinha@redhat.com>
Date: Thu, 12 Sep 2024 11:48:38 +0530
Subject: [PATCH 4/9] accel/kvm: refactor dirty ring setup
RH-Author: Peter Xu <peterx@redhat.com>
RH-MergeRequest: 285: KVM: Dynamic sized kvm memslots array
RH-Jira: RHEL-57685
RH-Acked-by: Juraj Marcin <None>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [3/7] 94f345d1e7ad6437dd2ce67ca7cad224c67aa48f (peterx/qemu-kvm)
Refactor setting up of dirty ring code in kvm_init() so that is can be
reused in the future patchsets.
Signed-off-by: Ani Sinha <anisinha@redhat.com>
Link: https://lore.kernel.org/r/20240912061838.4501-1-anisinha@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 28ed7f9761eb273e7dedcfdc0507d158106d0451)
Signed-off-by: Peter Xu <peterx@redhat.com>
---
accel/kvm/kvm-all.c | 88 +++++++++++++++++++++++++--------------------
1 file changed, 50 insertions(+), 38 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index d86d1b515a..8187ad3964 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2439,6 +2439,55 @@ static int find_kvm_machine_type(MachineState *ms)
return type;
}
+static int kvm_setup_dirty_ring(KVMState *s)
+{
+ uint64_t dirty_log_manual_caps;
+ int ret;
+
+ /*
+ * Enable KVM dirty ring if supported, otherwise fall back to
+ * dirty logging mode
+ */
+ ret = kvm_dirty_ring_init(s);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /*
+ * KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is not needed when dirty ring is
+ * enabled. More importantly, KVM_DIRTY_LOG_INITIALLY_SET will assume no
+ * page is wr-protected initially, which is against how kvm dirty ring is
+ * usage - kvm dirty ring requires all pages are wr-protected at the very
+ * beginning. Enabling this feature for dirty ring causes data corruption.
+ *
+ * TODO: Without KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 and kvm clear dirty log,
+ * we may expect a higher stall time when starting the migration. In the
+ * future we can enable KVM_CLEAR_DIRTY_LOG to work with dirty ring too:
+ * instead of clearing dirty bit, it can be a way to explicitly wr-protect
+ * guest pages.
+ */
+ if (!s->kvm_dirty_ring_size) {
+ dirty_log_manual_caps =
+ kvm_check_extension(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
+ dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
+ KVM_DIRTY_LOG_INITIALLY_SET);
+ s->manual_dirty_log_protect = dirty_log_manual_caps;
+ if (dirty_log_manual_caps) {
+ ret = kvm_vm_enable_cap(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, 0,
+ dirty_log_manual_caps);
+ if (ret) {
+ warn_report("Trying to enable capability %"PRIu64" of "
+ "KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 but failed. "
+ "Falling back to the legacy mode. ",
+ dirty_log_manual_caps);
+ s->manual_dirty_log_protect = 0;
+ }
+ }
+ }
+
+ return 0;
+}
+
static int kvm_init(MachineState *ms)
{
MachineClass *mc = MACHINE_GET_CLASS(ms);
@@ -2458,7 +2507,6 @@ static int kvm_init(MachineState *ms)
const KVMCapabilityInfo *missing_cap;
int ret;
int type;
- uint64_t dirty_log_manual_caps;
qemu_mutex_init(&kml_slots_lock);
@@ -2570,47 +2618,11 @@ static int kvm_init(MachineState *ms)
s->coalesced_pio = s->coalesced_mmio &&
kvm_check_extension(s, KVM_CAP_COALESCED_PIO);
- /*
- * Enable KVM dirty ring if supported, otherwise fall back to
- * dirty logging mode
- */
- ret = kvm_dirty_ring_init(s);
+ ret = kvm_setup_dirty_ring(s);
if (ret < 0) {
goto err;
}
- /*
- * KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is not needed when dirty ring is
- * enabled. More importantly, KVM_DIRTY_LOG_INITIALLY_SET will assume no
- * page is wr-protected initially, which is against how kvm dirty ring is
- * usage - kvm dirty ring requires all pages are wr-protected at the very
- * beginning. Enabling this feature for dirty ring causes data corruption.
- *
- * TODO: Without KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 and kvm clear dirty log,
- * we may expect a higher stall time when starting the migration. In the
- * future we can enable KVM_CLEAR_DIRTY_LOG to work with dirty ring too:
- * instead of clearing dirty bit, it can be a way to explicitly wr-protect
- * guest pages.
- */
- if (!s->kvm_dirty_ring_size) {
- dirty_log_manual_caps =
- kvm_check_extension(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
- dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
- KVM_DIRTY_LOG_INITIALLY_SET);
- s->manual_dirty_log_protect = dirty_log_manual_caps;
- if (dirty_log_manual_caps) {
- ret = kvm_vm_enable_cap(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, 0,
- dirty_log_manual_caps);
- if (ret) {
- warn_report("Trying to enable capability %"PRIu64" of "
- "KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 but failed. "
- "Falling back to the legacy mode. ",
- dirty_log_manual_caps);
- s->manual_dirty_log_protect = 0;
- }
- }
- }
-
#ifdef KVM_CAP_VCPU_EVENTS
s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS);
#endif
--
2.39.3
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