* Igor Mammedov (imamm...@redhat.com) wrote: > On Thu, 14 Dec 2017 15:20:10 +0000 > "Dr. David Alan Gilbert" <dgilb...@redhat.com> wrote: > > > * Igor Mammedov (imamm...@redhat.com) wrote: > > > On Wed, 13 Dec 2017 18:08:02 +0000 > > > "Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> wrote: > > > > > > > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > > > > > > > Move the log_dirty check into vhost_section. > > > > > > > > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > > > > --- > > > > hw/virtio/trace-events | 3 +++ > > > > hw/virtio/vhost.c | 20 +++++++++++++------- > > > > 2 files changed, 16 insertions(+), 7 deletions(-) > > > > > > > > diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events > > > > index 775461ae98..4a493bcd46 100644 > > > > --- a/hw/virtio/trace-events > > > > +++ b/hw/virtio/trace-events > > > > @@ -1,5 +1,8 @@ > > > > # See docs/devel/tracing.txt for syntax documentation. > > > > > > > > +# hw/virtio/vhost.c > > > > +vhost_section(const char *name, int r) "%s:%d" > > > > + > > > > # hw/virtio/virtio.c > > > > virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, > > > > unsigned out_num) "elem %p size %zd in_num %u out_num %u" > > > > virtqueue_fill(void *vq, const void *elem, unsigned int len, unsigned > > > > int idx) "vq %p elem %p len %u idx %u" > > > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > > > > index e4290ce93d..e923219e63 100644 > > > > --- a/hw/virtio/vhost.c > > > > +++ b/hw/virtio/vhost.c > > > > @@ -27,6 +27,7 @@ > > > > #include "hw/virtio/virtio-access.h" > > > > #include "migration/blocker.h" > > > > #include "sysemu/dma.h" > > > > +#include "trace.h" > > > > > > > > /* enabled until disconnected backend stabilizes */ > > > > #define _VHOST_DEBUG 1 > > > > @@ -567,18 +568,12 @@ static void vhost_set_memory(MemoryListener > > > > *listener, > > > > memory_listener); > > > > hwaddr start_addr = section->offset_within_address_space; > > > > ram_addr_t size = int128_get64(section->size); > > > > - bool log_dirty = > > > > - memory_region_get_dirty_log_mask(section->mr) & ~(1 << > > > > DIRTY_MEMORY_MIGRATION); > > > > int s = offsetof(struct vhost_memory, regions) + > > > > (dev->mem->nregions + 1) * sizeof dev->mem->regions[0]; > > > > void *ram; > > > > > > > > dev->mem = g_realloc(dev->mem, s); > > > > > > > > - if (log_dirty) { > > > > - add = false; > > > > - } > > > > - > > > > assert(size); > > > > > > > > /* Optimize no-change case. At least cirrus_vga does this a lot at > > > > this time. */ > > > > @@ -611,8 +606,19 @@ static void vhost_set_memory(MemoryListener > > > > *listener, > > > > > > > > static bool vhost_section(MemoryRegionSection *section) > > > > { > > > > - return memory_region_is_ram(section->mr) && > > > > + bool result; > > > > + bool log_dirty = memory_region_get_dirty_log_mask(section->mr) & > > > > + ~(1 << DIRTY_MEMORY_MIGRATION); > > > > + result = memory_region_is_ram(section->mr) && > > > > !memory_region_is_rom(section->mr); > > > > + > > > > + /* Vhost doesn't handle any block which is doing dirty-tracking > > > > other > > > > + * than migration; this typically fires on VGA areas. > > > > + */ > > > > + result &= !log_dirty; > > > before patch even if log_dirty, vhost_set_memory will still proceed > > > and may remove dirty section from memmap and set memory_changed = true > > > > > > but with this patch it will just ignore such section, > > > I'm not sure it's right (it might be right with new approach add/nop > > > but then this patch should go after new code in place and old one > > > if gone). > > > > I thought about that, but then I came to the conclusion that the whole > > idea is that we're supposed to be ignoring these regions - so why > > should they cause any change to the behaviour of vhost at all? > > Thus this way seems safer. > the thing is that with originally with old code backend will use memap > with not yet dirty region, then after region becomes dirty current code > will REMOVE dirty region from map and NOTIFY backend. > > While this patch is fine for new approach as memmap is build from scratch, > it doesn't look correct for current code since region that just became > dirty will not be removed from memap and might be used backend. > Whether it would really break something or not I'm not sure, > maybe Michael may Ack this patch ii using dirty region is fine.
That's OK; I can add the check to vhost_region_add_section when I initially create it, and then swing this change around nearer to the end of the patchset, so that now we're using the new code. Dave > > > > Dave > > > > > > + > > > > + trace_vhost_section(section->mr->name, result); > > > > + return result; > > > > } > > > > > > > > static void vhost_begin(MemoryListener *listener) > > > > > -- > > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK