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[PULL 13/20] KVM: Create the KVMSlot dirty bitmap on flag changes
From: |
Paolo Bonzini |
Subject: |
[PULL 13/20] KVM: Create the KVMSlot dirty bitmap on flag changes |
Date: |
Mon, 17 May 2021 07:19:54 -0400 |
From: Peter Xu <peterx@redhat.com>
Previously we have two places that will create the per KVMSlot dirty
bitmap:
1. When a newly created KVMSlot has dirty logging enabled,
2. When the first log_sync() happens for a memory slot.
The 2nd case is lazy-init, while the 1st case is not (which is a fix
of what the 2nd case missed).
To do explicit initialization of dirty bitmaps, what we're missing is
to create the dirty bitmap when the slot changed from not-dirty-track
to dirty-track. Do that in kvm_slot_update_flags().
With that, we can safely remove the 2nd lazy-init.
This change will be needed for kvm dirty ring because kvm dirty ring
does not use the log_sync() interface at all.
Also move all the pre-checks into kvm_slot_init_dirty_bitmap().
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210506160549.130416-4-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
accel/kvm/kvm-all.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f8980e155b..5bc40fd71b 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -177,6 +177,8 @@ static QemuMutex kml_slots_lock;
#define kvm_slots_lock() qemu_mutex_lock(&kml_slots_lock)
#define kvm_slots_unlock() qemu_mutex_unlock(&kml_slots_lock)
+static void kvm_slot_init_dirty_bitmap(KVMSlot *mem);
+
static inline void kvm_resample_fd_remove(int gsi)
{
KVMResampleFd *rfd;
@@ -500,6 +502,7 @@ static int kvm_slot_update_flags(KVMMemoryListener *kml,
KVMSlot *mem,
return 0;
}
+ kvm_slot_init_dirty_bitmap(mem);
return kvm_set_user_memory_region(kml, mem, false);
}
@@ -584,8 +587,12 @@ static int
kvm_get_dirty_pages_log_range(MemoryRegionSection *section,
#define ALIGN(x, y) (((x)+(y)-1) & ~((y)-1))
/* Allocate the dirty bitmap for a slot */
-static void kvm_memslot_init_dirty_bitmap(KVMSlot *mem)
+static void kvm_slot_init_dirty_bitmap(KVMSlot *mem)
{
+ if (!(mem->flags & KVM_MEM_LOG_DIRTY_PAGES) || mem->dirty_bmap) {
+ return;
+ }
+
/*
* XXX bad kernel interface alert
* For dirty bitmap, kernel allocates array of size aligned to
@@ -640,11 +647,6 @@ static int
kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
goto out;
}
- if (!mem->dirty_bmap) {
- /* Allocate on the first log_sync, once and for all */
- kvm_memslot_init_dirty_bitmap(mem);
- }
-
d.dirty_bitmap = mem->dirty_bmap;
d.slot = mem->slot | (kml->as_id << 16);
ret = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d);
@@ -1181,14 +1183,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
mem->start_addr = start_addr;
mem->ram = ram;
mem->flags = kvm_mem_flags(mr);
-
- if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
- /*
- * Reallocate the bmap; it means it doesn't disappear in
- * middle of a migrate.
- */
- kvm_memslot_init_dirty_bitmap(mem);
- }
+ kvm_slot_init_dirty_bitmap(mem);
err = kvm_set_user_memory_region(kml, mem, true);
if (err) {
fprintf(stderr, "%s: error registering slot: %s\n", __func__,
--
2.27.0
- [PULL 05/20] backends/tpm: Replace qemu_mutex_lock calls with QEMU_LOCK_GUARD, (continued)
- [PULL 05/20] backends/tpm: Replace qemu_mutex_lock calls with QEMU_LOCK_GUARD, Paolo Bonzini, 2021/05/17
- [PULL 03/20] configure: simplify assignment to GIT_SUBMODULES, Paolo Bonzini, 2021/05/17
- [PULL 04/20] hw/mem/nvdimm: Use Kconfig 'imply' instead of 'depends on', Paolo Bonzini, 2021/05/17
- [PULL 01/20] configure: Only clone softfloat-3 repositories if TCG is enabled, Paolo Bonzini, 2021/05/17
- [PULL 07/20] meson: bump submodule to 0.57.2, Paolo Bonzini, 2021/05/17
- [PULL 10/20] KVM: do not allow setting properties at runtime, Paolo Bonzini, 2021/05/17
- [PULL 09/20] qtest: add a QOM object for qtest, Paolo Bonzini, 2021/05/17
- [PULL 06/20] i386/cpu: Expose AVX_VNNI instruction to guest, Paolo Bonzini, 2021/05/17
- [PULL 11/20] memory: Introduce log_sync_global() to memory listener, Paolo Bonzini, 2021/05/17
- [PULL 12/20] KVM: Use a big lock to replace per-kml slots_lock, Paolo Bonzini, 2021/05/17
- [PULL 13/20] KVM: Create the KVMSlot dirty bitmap on flag changes,
Paolo Bonzini <=
- [PULL 14/20] KVM: Provide helper to get kvm dirty log, Paolo Bonzini, 2021/05/17
- [PULL 15/20] KVM: Provide helper to sync dirty bitmap from slot to ramblock, Paolo Bonzini, 2021/05/17
- [PULL 16/20] KVM: Simplify dirty log sync in kvm_set_phys_mem, Paolo Bonzini, 2021/05/17
- [PULL 18/20] KVM: Add dirty-ring-size property, Paolo Bonzini, 2021/05/17
- [PULL 17/20] KVM: Cache kvm slot dirty bitmap size, Paolo Bonzini, 2021/05/17
- [PULL 19/20] KVM: Disable manual dirty log when dirty ring enabled, Paolo Bonzini, 2021/05/17
- [PULL 20/20] KVM: Dirty ring support, Paolo Bonzini, 2021/05/17
- Re: [PULL 00/20] Misc patches for 2020-05-17, no-reply, 2021/05/17
- Re: [PULL 00/20] Misc patches for 2020-05-17, Peter Maydell, 2021/05/18