On 14.01.21 00:27, Alex Williamson wrote:
> On Thu, 7 Jan 2021 14:34:16 +0100
> David Hildenbrand <da...@redhat.com> wrote:
>
>> Implement support for RamDiscardMgr, to prepare for virtio-mem
>> support. Instead of mapping the whole memory section, we only map
>> "populated" parts and update the mapping when notified about
>> discarding/population of memory via the RamDiscardListener. Similarly, when
>> syncing the dirty bitmaps, sync only the actually mapped (populated) parts
>> by replaying via the notifier.
>>
>> Using virtio-mem with vfio is still blocked via
>> ram_block_discard_disable()/ram_block_discard_require() after this patch.
>>
>> Cc: Paolo Bonzini <pbonz...@redhat.com>
>> Cc: "Michael S. Tsirkin" <m...@redhat.com>
>> Cc: Alex Williamson <alex.william...@redhat.com>
>> Cc: Dr. David Alan Gilbert <dgilb...@redhat.com>
>> Cc: Igor Mammedov <imamm...@redhat.com>
>> Cc: Pankaj Gupta <pankaj.gupta.li...@gmail.com>
>> Cc: Peter Xu <pet...@redhat.com>
>> Cc: Auger Eric <eric.au...@redhat.com>
>> Cc: Wei Yang <richard.weiy...@linux.alibaba.com>
>> Cc: teawater <teawat...@linux.alibaba.com>
>> Cc: Marek Kedzierski <mkedz...@redhat.com>
>> Signed-off-by: David Hildenbrand <da...@redhat.com>
>> ---
>> hw/vfio/common.c | 200 ++++++++++++++++++++++++++++++++++
>> include/hw/vfio/vfio-common.h | 12 ++
>> 2 files changed, 212 insertions(+)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 6ff1daa763..2bd219cf1d 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -654,6 +654,136 @@ out:
>> rcu_read_unlock();
>> }
>>
>> +static void vfio_ram_discard_notify_discard(RamDiscardListener *rdl,
>> + const MemoryRegion *mr,
>> + ram_addr_t offset, ram_addr_t
>> size)
>> +{
>> + VFIORamDiscardListener *vrdl = container_of(rdl, VFIORamDiscardListener,
>> + listener);
>> + const hwaddr mr_start = MAX(offset, vrdl->offset_within_region);
>> + const hwaddr mr_end = MIN(offset + size,
>> + vrdl->offset_within_region + vrdl->size);
>> + const hwaddr iova = mr_start - vrdl->offset_within_region +
>> + vrdl->offset_within_address_space;
>> + int ret;
>> +
>> + if (mr_start >= mr_end) {
>> + return;
>> + }
>> +
>> + /* Unmap with a single call. */
>> + ret = vfio_dma_unmap(vrdl->container, iova, mr_end - mr_start, NULL);
>> + if (ret) {
>> + error_report("%s: vfio_dma_unmap() failed: %s", __func__,
>> + strerror(-ret));
>> + }
>> +}
>> +
>> +static int vfio_ram_discard_notify_populate(RamDiscardListener *rdl,
>> + const MemoryRegion *mr,
>> + ram_addr_t offset, ram_addr_t
>> size)
>> +{
>> + VFIORamDiscardListener *vrdl = container_of(rdl, VFIORamDiscardListener,
>> + listener);
>> + const hwaddr mr_end = MIN(offset + size,
>> + vrdl->offset_within_region + vrdl->size);
>> + hwaddr mr_start = MAX(offset, vrdl->offset_within_region);
>> + hwaddr mr_next, iova;
>> + void *vaddr;
>> + int ret;
>> +
>> + /*
>> + * Map in (aligned within memory region) minimum granularity, so we can
>> + * unmap in minimum granularity later.
>> + */
>> + for (; mr_start < mr_end; mr_start = mr_next) {
>> + mr_next = ROUND_UP(mr_start + 1, vrdl->granularity);
>> + mr_next = MIN(mr_next, mr_end);
>> +
>> + iova = mr_start - vrdl->offset_within_region +
>> + vrdl->offset_within_address_space;
>> + vaddr = memory_region_get_ram_ptr(vrdl->mr) + mr_start;
>> +
>> + ret = vfio_dma_map(vrdl->container, iova, mr_next - mr_start,
>> + vaddr, mr->readonly);
>> + if (ret) {
>> + /* Rollback */
>> + vfio_ram_discard_notify_discard(rdl, mr, offset, size);
>> + return ret;
>> + }
>> + }
>> + return 0;
>> +}
>> +
>> +static void vfio_ram_discard_notify_discard_all(RamDiscardListener *rdl,
>> + const MemoryRegion *mr)
>> +{
>> + VFIORamDiscardListener *vrdl = container_of(rdl, VFIORamDiscardListener,
>> + listener);
>> + int ret;
>> +
>> + /* Unmap with a single call. */
>> + ret = vfio_dma_unmap(vrdl->container, vrdl->offset_within_address_space,
>> + vrdl->size, NULL);
>> + if (ret) {
>> + error_report("%s: vfio_dma_unmap() failed: %s", __func__,
>> + strerror(-ret));
>> + }
>> +}
>> +
>> +static void vfio_register_ram_discard_notifier(VFIOContainer *container,
>> + MemoryRegionSection *section)
>> +{
>> + RamDiscardMgr *rdm = memory_region_get_ram_discard_mgr(section->mr);
>> + RamDiscardMgrClass *rdmc = RAM_DISCARD_MGR_GET_CLASS(rdm);
>> + VFIORamDiscardListener *vrdl;
>> +
>> + vrdl = g_new0(VFIORamDiscardListener, 1);
>> + vrdl->container = container;
>> + vrdl->mr = section->mr;
>> + vrdl->offset_within_region = section->offset_within_region;
>> + vrdl->offset_within_address_space =
>> section->offset_within_address_space;
>> + vrdl->size = int128_get64(section->size);
>> + vrdl->granularity = rdmc->get_min_granularity(rdm, section->mr);
>> +
>> + /* Ignore some corner cases not relevant in practice. */
>> + g_assert(QEMU_IS_ALIGNED(vrdl->offset_within_region, TARGET_PAGE_SIZE));
>> + g_assert(QEMU_IS_ALIGNED(vrdl->offset_within_address_space,
>> + TARGET_PAGE_SIZE));
>> + g_assert(QEMU_IS_ALIGNED(vrdl->size, TARGET_PAGE_SIZE));
>
> Should probably toss in a test of vrdl->granularity vs
> container->pgsizes too, right? Looks good otherwise:
Makes sense as a sanity check. What about
g_assert(vrdl->granularity && !is_power_of_2(vrdl->granularity));
g_assert(vrdl->granularity >= 1 << ctz64(container->pgsizes));
?
Thanks!
>
> Reviewed-by: Alex Williamson <alex.william...@redhat.com>
> Acked-by: Alex Williamson <alex.william...@redhat.com>
Thanks!
--
Thanks,
David / dhildenb
