When doing ditry tracking or calculating dirty tracking range, readonly regions can be bypassed, because corresponding DMA mappings are readonly and never become dirty.
This can optimize dirty tracking a bit for passthrough device. Signed-off-by: Zhenzhong Duan <[email protected]> --- hw/vfio/listener.c | 46 +++++++++++++++++++++++++++++++++----------- hw/vfio/trace-events | 1 + 2 files changed, 36 insertions(+), 11 deletions(-) diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c index 3b48f6796c..ca2377d860 100644 --- a/hw/vfio/listener.c +++ b/hw/vfio/listener.c @@ -76,8 +76,13 @@ static bool vfio_log_sync_needed(const VFIOContainer *bcontainer) return true; } -static bool vfio_listener_skipped_section(MemoryRegionSection *section) +static bool vfio_listener_skipped_section(MemoryRegionSection *section, + bool bypass_ro) { + if (bypass_ro && section->readonly) { + return true; + } + return (!memory_region_is_ram(section->mr) && !memory_region_is_iommu(section->mr)) || memory_region_is_protected(section->mr) || @@ -368,9 +373,9 @@ static bool vfio_known_safe_misalignment(MemoryRegionSection *section) } static bool vfio_listener_valid_section(MemoryRegionSection *section, - const char *name) + bool bypass_ro, const char *name) { - if (vfio_listener_skipped_section(section)) { + if (vfio_listener_skipped_section(section, bypass_ro)) { trace_vfio_listener_region_skip(name, section->offset_within_address_space, section->offset_within_address_space + @@ -497,7 +502,7 @@ void vfio_container_region_add(VFIOContainer *bcontainer, int ret; Error *err = NULL; - if (!vfio_listener_valid_section(section, "region_add")) { + if (!vfio_listener_valid_section(section, false, "region_add")) { return; } @@ -663,7 +668,7 @@ static void vfio_listener_region_del(MemoryListener *listener, int ret; bool try_unmap = true; - if (!vfio_listener_valid_section(section, "region_del")) { + if (!vfio_listener_valid_section(section, false, "region_del")) { return; } @@ -722,11 +727,11 @@ static void vfio_listener_region_del(MemoryListener *listener, } /* - * Fake an IOTLB entry for identity mapping which is needed by dirty - * tracking. In fact, in unmap_bitmap, only translated_addr field is - * used to set dirty bitmap. + * Fake an IOTLB entry for writable identity mapping which is needed + * by dirty tracking. In fact, in unmap_bitmap, only translated_addr + * field is used to set dirty bitmap. */ - if (!memory_region_is_iommu(section->mr)) { + if (!memory_region_is_iommu(section->mr) && !section->readonly) { entry.iova = iova; entry.translated_addr = iova; iotlb = &entry; @@ -834,7 +839,8 @@ static void vfio_dirty_tracking_update(MemoryListener *listener, container_of(listener, VFIODirtyRangesListener, listener); hwaddr iova, end; - if (!vfio_listener_valid_section(section, "tracking_update") || + /* Bypass readonly section as it never becomes dirty */ + if (!vfio_listener_valid_section(section, true, "tracking_update") || !vfio_get_section_iova_range(dirty->bcontainer, section, &iova, &end, NULL)) { return; @@ -1093,6 +1099,19 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) if (!mr) { goto out_unlock; } + + /* + * The mapping is readonly when either it's a readonly mapping in guest + * or mapped target is readonly, bypass it for dirty tracking as it + * never becomes dirty. + */ + if (!(iotlb->perm & IOMMU_WO) || mr->readonly) { + trace_vfio_iommu_map_dirty_notify_skip_ro(iova, + iova + iotlb->addr_mask); + rcu_read_unlock(); + return; + } + translated_addr = memory_region_get_ram_addr(mr) + xlat; ret = vfio_container_query_dirty_bitmap(bcontainer, iova, iotlb->addr_mask + 1, @@ -1228,7 +1247,12 @@ static void vfio_listener_log_sync(MemoryListener *listener, int ret; Error *local_err = NULL; - if (vfio_listener_skipped_section(section)) { + /* + * Bypass readonly section as it never becomes dirty, iommu memory section + * is RW and never bypassed. The readonly mappings in iommu MR are bypassed + * in vfio_iommu_map_dirty_notify(). + */ + if (vfio_listener_skipped_section(section, true)) { return; } diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index 3c62bab764..180e3d526b 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -103,6 +103,7 @@ vfio_listener_region_del(uint64_t start, uint64_t end) "region_del 0x%"PRIx64" - vfio_device_dirty_tracking_update(uint64_t start, uint64_t end, uint64_t min, uint64_t max) "section 0x%"PRIx64" - 0x%"PRIx64" -> update [0x%"PRIx64" - 0x%"PRIx64"]" vfio_device_dirty_tracking_start(int nr_ranges, uint64_t min32, uint64_t max32, uint64_t min64, uint64_t max64, uint64_t minpci, uint64_t maxpci) "nr_ranges %d 32:[0x%"PRIx64" - 0x%"PRIx64"], 64:[0x%"PRIx64" - 0x%"PRIx64"], pci64:[0x%"PRIx64" - 0x%"PRIx64"]" vfio_iommu_map_dirty_notify(uint64_t iova_start, uint64_t iova_end) "iommu dirty @ 0x%"PRIx64" - 0x%"PRIx64 +vfio_iommu_map_dirty_notify_skip_ro(uint64_t iova_start, uint64_t iova_end) "iommu dirty @ 0x%"PRIx64" - 0x%"PRIx64 # container.c vfio_container_query_dirty_bitmap(uint64_t iova, uint64_t size, uint64_t backend_flag, uint64_t bitmap_size, uint64_t translated_addr, uint64_t dirty_pages) "iova=0x%"PRIx64" size=0x%"PRIx64" backend_flag=0x%"PRIx64" bitmap_size=0x%"PRIx64" gpa=0x%"PRIx64" dirty_pages=%"PRIu64 -- 2.47.1
