From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
qemu-devel@nongnu.org, "Michael S . Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH RFC 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock
Date: Wed, 25 Mar 2020 18:47:07 +0000 [thread overview]
Message-ID: <20200325184707.GE2635@work-vm> (raw)
In-Reply-To: <20200205141749.378044-7-peterx@redhat.com>
* Peter Xu (peterx@redhat.com) wrote:
> kvm_physical_sync_dirty_bitmap() calculates the ramblock offset in an
> awkward way from the MemoryRegionSection that passed in from the
> caller. The truth is for each KVMSlot the ramblock offset never
> change for the lifecycle. Cache the ramblock offset for each KVMSlot
> into the structure when the KVMSlot is created.
>
> With that, we can further simplify kvm_physical_sync_dirty_bitmap()
> with a helper to sync KVMSlot dirty bitmap to the ramblock dirty
> bitmap of a specific KVMSlot.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> accel/kvm/kvm-all.c | 37 +++++++++++++++++--------------------
> include/sysemu/kvm_int.h | 2 ++
> 2 files changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 608216fd53..f81e7a644b 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -515,15 +515,12 @@ static void kvm_log_stop(MemoryListener *listener,
> }
>
> /* get kvm's dirty pages bitmap and update qemu's */
> -static int kvm_get_dirty_pages_log_range(MemoryRegionSection *section,
> - unsigned long *bitmap)
> +static void kvm_slot_sync_dirty_pages(KVMSlot *slot)
> {
> - ram_addr_t start = section->offset_within_region +
> - memory_region_get_ram_addr(section->mr);
> - ram_addr_t pages = int128_get64(section->size) / qemu_real_host_page_size;
> + ram_addr_t start = slot->ram_start_offset;
> + ram_addr_t pages = slot->memory_size / qemu_real_host_page_size;
>
> - cpu_physical_memory_set_dirty_lebitmap(bitmap, start, pages);
> - return 0;
> + cpu_physical_memory_set_dirty_lebitmap(slot->dirty_bmap, start, pages);
> }
>
> #define ALIGN(x, y) (((x)+(y)-1) & ~((y)-1))
> @@ -582,12 +579,10 @@ static void kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
> KVMState *s = kvm_state;
> KVMSlot *mem;
> hwaddr start_addr, size;
> - hwaddr slot_size, slot_offset = 0;
> + hwaddr slot_size;
>
> size = kvm_align_section(section, &start_addr);
> while (size) {
> - MemoryRegionSection subsection = *section;
> -
> slot_size = MIN(kvm_max_slot_size, size);
> mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
> if (!mem) {
> @@ -596,12 +591,7 @@ static void kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
> }
>
> 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, mem->dirty_bmap);
> -
> - slot_offset += slot_size;
> + kvm_slot_sync_dirty_pages(mem);
> start_addr += slot_size;
> size -= slot_size;
> }
> @@ -1023,7 +1013,8 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
> int err;
> MemoryRegion *mr = section->mr;
> bool writeable = !mr->readonly && !mr->rom_device;
> - hwaddr start_addr, size, slot_size;
> + hwaddr start_addr, size, slot_size, mr_offset;
> + ram_addr_t ram_start_offset;
> void *ram;
>
> if (!memory_region_is_ram(mr)) {
> @@ -1041,9 +1032,13 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
> return;
> }
>
> - /* use aligned delta to align the ram address */
> - ram = memory_region_get_ram_ptr(mr) + section->offset_within_region +
> - (start_addr - section->offset_within_address_space);
> + /* The offset of the kvmslot within the memory region */
> + mr_offset = section->offset_within_region + start_addr -
> + section->offset_within_address_space;
> +
> + /* use aligned delta to align the ram address and offset */
> + ram = memory_region_get_ram_ptr(mr) + mr_offset;
> + ram_start_offset = memory_region_get_ram_addr(mr) + mr_offset;
>
> kvm_slots_lock(kml);
>
> @@ -1082,6 +1077,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
> mem->as_id = kml->as_id;
> mem->memory_size = slot_size;
> mem->start_addr = start_addr;
> + mem->ram_start_offset = ram_start_offset;
> mem->ram = ram;
> mem->flags = kvm_mem_flags(mr);
> kvm_slot_init_dirty_bitmap(mem);
> @@ -1092,6 +1088,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
> abort();
> }
> start_addr += slot_size;
> + ram_start_offset += slot_size;
> ram += slot_size;
> size -= slot_size;
> } while (size);
> diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
> index 4434e15ec7..1a19bfef80 100644
> --- a/include/sysemu/kvm_int.h
> +++ b/include/sysemu/kvm_int.h
> @@ -25,6 +25,8 @@ typedef struct KVMSlot
> unsigned long *dirty_bmap;
> /* Cache of the address space ID */
> int as_id;
> + /* Cache of the offset in ram address space */
> + ram_addr_t ram_start_offset;
> } KVMSlot;
>
> typedef struct KVMMemoryListener {
> --
> 2.24.1
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2020-03-25 18:49 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 14:17 [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) Peter Xu
2020-02-05 14:17 ` [PATCH RFC 1/9] KVM: Fixup kvm_log_clear_one_slot() ioctl return check Peter Xu
2020-03-25 16:34 ` Dr. David Alan Gilbert
2020-03-25 17:43 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 2/9] linux-headers: Update Peter Xu
2020-02-05 14:17 ` [PATCH RFC 3/9] memory: Introduce log_sync_global() to memory listener Peter Xu
2020-03-25 16:52 ` Dr. David Alan Gilbert
2020-03-25 17:02 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 4/9] KVM: Create the KVMSlot dirty bitmap on flag changes Peter Xu
2020-03-25 17:44 ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 5/9] KVM: Provide helper to get kvm dirty log Peter Xu
2020-03-25 17:52 ` Dr. David Alan Gilbert
2020-03-25 18:15 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock Peter Xu
2020-03-25 18:47 ` Dr. David Alan Gilbert [this message]
2020-02-05 14:17 ` [PATCH RFC 7/9] KVM: Cache kvm slot dirty bitmap size Peter Xu
2020-03-25 18:49 ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 8/9] KVM: Add dirty-ring-size property Peter Xu
2020-03-25 20:00 ` Dr. David Alan Gilbert
2020-03-25 20:42 ` Peter Xu
2020-03-26 13:41 ` Dr. David Alan Gilbert
2020-03-26 16:03 ` Peter Xu
2020-03-25 20:14 ` Dr. David Alan Gilbert
2020-03-25 20:48 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 9/9] KVM: Dirty ring support Peter Xu
2020-03-25 20:41 ` Dr. David Alan Gilbert
2020-03-25 21:32 ` Peter Xu
2020-03-26 14:14 ` Dr. David Alan Gilbert
2020-03-26 16:10 ` Peter Xu
2020-02-05 14:51 ` [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) no-reply
2020-03-03 17:32 ` Peter Xu
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