From ea776d15adc021a9f38179d27227a7f4d90a8698 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Thu, 6 May 2021 12:05:42 -0400 Subject: [PATCH] KVM: Create the KVMSlot dirty bitmap on flag changes 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 Signed-off-by: Peter Xu Message-Id: <20210506160549.130416-4-peterx@redhat.com> Signed-off-by: Paolo Bonzini --- 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__,