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KVM: Provide helper to get kvm dirty log

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Provide a helper kvm_slot_get_dirty_log() to make the function
kvm_physical_sync_dirty_bitmap() clearer.  We can even cache the as_id
into KVMSlot when it is created, so that we don't even need to pass it
down every time.

Since at it, remove return value of kvm_physical_sync_dirty_bitmap()
because it should never fail.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210506160549.130416-5-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Xu 2021-05-06 12:05:43 -04:00 committed by Paolo Bonzini
parent ea776d15ad
commit e65e5f50db
2 changed files with 32 additions and 22 deletions
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52
accel/kvm/kvm-all.c
View file

@ -615,6 +615,30 @@ static void kvm_slot_init_dirty_bitmap(KVMSlot *mem)
mem->dirty_bmap = g_malloc0(bitmap_size);
}
/*
* Sync dirty bitmap from kernel to KVMSlot.dirty_bmap, return true if
* succeeded, false otherwise
*/
static bool kvm_slot_get_dirty_log(KVMState *s, KVMSlot *slot)
{
struct kvm_dirty_log d = {};
int ret;
d.dirty_bitmap = slot->dirty_bmap;
d.slot = slot->slot | (slot->as_id << 16);
ret = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d);
if (ret == -ENOENT) {
/* kernel does not have dirty bitmap in this slot */
ret = 0;
}
if (ret) {
error_report_once("%s: KVM_GET_DIRTY_LOG failed with %d",
__func__, ret);
}
return ret == 0;
}
/**
* kvm_physical_sync_dirty_bitmap - Sync dirty bitmap from kernel space
*
@ -626,15 +650,13 @@ static void kvm_slot_init_dirty_bitmap(KVMSlot *mem)
* @kml: the KVM memory listener object
* @section: the memory section to sync the dirty bitmap with
*/
static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
MemoryRegionSection *section)
static void kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
MemoryRegionSection *section)
{
KVMState *s = kvm_state;
struct kvm_dirty_log d = {};
KVMSlot *mem;
hwaddr start_addr, size;
hwaddr slot_size, slot_offset = 0;
int ret = 0;
size = kvm_align_section(section, &start_addr);
while (size) {
@ -644,19 +666,10 @@ static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
if (!mem) {
/* We don't have a slot if we want to trap every access. */
goto out;
return;
}
d.dirty_bitmap = mem->dirty_bmap;
d.slot = mem->slot | (kml->as_id << 16);
ret = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d);
if (ret == -ENOENT) {
/* kernel does not have dirty bitmap in this slot */
ret = 0;
} else if (ret < 0) {
error_report("ioctl KVM_GET_DIRTY_LOG failed: %d", errno);
goto out;
} else {
if (kvm_slot_get_dirty_log(s, mem)) {
subsection.offset_within_region += slot_offset;
subsection.size = int128_make64(slot_size);
kvm_get_dirty_pages_log_range(&subsection, d.dirty_bitmap);
@ -666,8 +679,6 @@ static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
start_addr += slot_size;
size -= slot_size;
}
out:
return ret;
}
/* Alignment requirement for KVM_CLEAR_DIRTY_LOG - 64 pages */
@ -1179,6 +1190,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
do {
slot_size = MIN(kvm_max_slot_size, size);
mem = kvm_alloc_slot(kml);
mem->as_id = kml->as_id;
mem->memory_size = slot_size;
mem->start_addr = start_addr;
mem->ram = ram;
@ -1221,14 +1233,10 @@ static void kvm_log_sync(MemoryListener *listener,
MemoryRegionSection *section)
{
KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener);
int r;
kvm_slots_lock();
r = kvm_physical_sync_dirty_bitmap(kml, section);
kvm_physical_sync_dirty_bitmap(kml, section);
kvm_slots_unlock();
if (r < 0) {
abort();
}
}
static void kvm_log_clear(MemoryListener *listener,

2
include/sysemu/kvm_int.h
View file

@ -23,6 +23,8 @@ typedef struct KVMSlot
int old_flags;
/* Dirty bitmap cache for the slot */
unsigned long *dirty_bmap;
/* Cache of the address space ID */
int as_id;
} KVMSlot;
typedef struct KVMMemoryListener {