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qemu-linux-user.openSUSE_Leap_42.3_Update
0146-memory-add-support-getting-and-usin.patch
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File 0146-memory-add-support-getting-and-usin.patch of Package qemu-linux-user.openSUSE_Leap_42.3_Update
From e96971f5cfe3e700109e2747923d22cf09483791 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann <kraxel@redhat.com> Date: Fri, 21 Apr 2017 11:16:25 +0200 Subject: [PATCH] memory: add support getting and using a dirty bitmap copy. This patch adds support for getting and using a local copy of the dirty bitmap. memory_region_snapshot_and_clear_dirty() will create a snapshot of the dirty bitmap for the specified range, clear the dirty bitmap and return the copy. The returned bitmap can be a bit larger than requested, the range is expanded so the code can copy unsigned longs from the bitmap and avoid atomic bit update operations. memory_region_snapshot_get_dirty() will return the dirty status of pages, pretty much like memory_region_get_dirty(), but using the copy returned by memory_region_copy_and_clear_dirty(). Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Message-id: 20170421091632.30900-3-kraxel@redhat.com Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> (cherry picked from commit 8deaf12ca1a7c89867df739dc9056080509628bd) [BR: Support for BSC#1084604 (and other useful vga fixes)] Signed-off-by: Bruce Rogers <brogers@suse.com> --- exec.c | 75 +++++++++++++++++++++++++++++++++++++++++ include/exec/memory.h | 47 ++++++++++++++++++++++++++ include/exec/ram_addr.h | 7 ++++ include/qemu/typedefs.h | 1 + memory.c | 17 ++++++++++ 5 files changed, 147 insertions(+) diff --git a/exec.c b/exec.c index 9ef33e4f65..dfe20f5ffc 100644 --- a/exec.c +++ b/exec.c @@ -223,6 +223,12 @@ struct CPUAddressSpace { MemoryListener tcg_as_listener; }; +struct DirtyBitmapSnapshot { + ram_addr_t start; + ram_addr_t end; + unsigned long dirty[]; +}; + #endif #if !defined(CONFIG_USER_ONLY) @@ -1061,6 +1067,75 @@ bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start, return dirty; } +DirtyBitmapSnapshot *cpu_physical_memory_snapshot_and_clear_dirty + (ram_addr_t start, ram_addr_t length, unsigned client) +{ + DirtyMemoryBlocks *blocks; + unsigned long align = 1UL << (TARGET_PAGE_BITS + BITS_PER_LEVEL); + ram_addr_t first = QEMU_ALIGN_DOWN(start, align); + ram_addr_t last = QEMU_ALIGN_UP(start + length, align); + DirtyBitmapSnapshot *snap; + unsigned long page, end, dest; + + snap = g_malloc0(sizeof(*snap) + + ((last - first) >> (TARGET_PAGE_BITS + 3))); + snap->start = first; + snap->end = last; + + page = first >> TARGET_PAGE_BITS; + end = last >> TARGET_PAGE_BITS; + dest = 0; + + rcu_read_lock(); + + blocks = atomic_rcu_read(&ram_list.dirty_memory[client]); + + while (page < end) { + unsigned long idx = page / DIRTY_MEMORY_BLOCK_SIZE; + unsigned long offset = page % DIRTY_MEMORY_BLOCK_SIZE; + unsigned long num = MIN(end - page, DIRTY_MEMORY_BLOCK_SIZE - offset); + + assert(QEMU_IS_ALIGNED(offset, (1 << BITS_PER_LEVEL))); + assert(QEMU_IS_ALIGNED(num, (1 << BITS_PER_LEVEL))); + offset >>= BITS_PER_LEVEL; + + bitmap_copy_and_clear_atomic(snap->dirty + dest, + blocks->blocks[idx] + offset, + num); + page += num; + dest += num >> BITS_PER_LEVEL; + } + + rcu_read_unlock(); + + if (tcg_enabled()) { + tlb_reset_dirty_range_all(start, length); + } + + return snap; +} + +bool cpu_physical_memory_snapshot_get_dirty(DirtyBitmapSnapshot *snap, + ram_addr_t start, + ram_addr_t length) +{ + unsigned long page, end; + + assert(start >= snap->start); + assert(start + length <= snap->end); + + end = TARGET_PAGE_ALIGN(start + length - snap->start) >> TARGET_PAGE_BITS; + page = (start - snap->start) >> TARGET_PAGE_BITS; + + while (page < end) { + if (test_bit(page, snap->dirty)) { + return true; + } + page++; + } + return false; +} + /* Called from RCU critical section */ hwaddr memory_region_section_get_iotlb(CPUState *cpu, MemoryRegionSection *section, diff --git a/include/exec/memory.h b/include/exec/memory.h index f20b191793..1e15e79d00 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -871,6 +871,53 @@ void memory_region_set_dirty(MemoryRegion *mr, hwaddr addr, */ bool memory_region_test_and_clear_dirty(MemoryRegion *mr, hwaddr addr, hwaddr size, unsigned client); + +/** + * memory_region_snapshot_and_clear_dirty: Get a snapshot of the dirty + * bitmap and clear it. + * + * Creates a snapshot of the dirty bitmap, clears the dirty bitmap and + * returns the snapshot. The snapshot can then be used to query dirty + * status, using memory_region_snapshot_get_dirty. Unlike + * memory_region_test_and_clear_dirty this allows to query the same + * page multiple times, which is especially useful for display updates + * where the scanlines often are not page aligned. + * + * The dirty bitmap region which gets copyed into the snapshot (and + * cleared afterwards) can be larger than requested. The boundaries + * are rounded up/down so complete bitmap longs (covering 64 pages on + * 64bit hosts) can be copied over into the bitmap snapshot. Which + * isn't a problem for display updates as the extra pages are outside + * the visible area, and in case the visible area changes a full + * display redraw is due anyway. Should other use cases for this + * function emerge we might have to revisit this implementation + * detail. + * + * Use g_free to release DirtyBitmapSnapshot. + * + * @mr: the memory region being queried. + * @addr: the address (relative to the start of the region) being queried. + * @size: the size of the range being queried. + * @client: the user of the logging information; typically %DIRTY_MEMORY_VGA. + */ +DirtyBitmapSnapshot *memory_region_snapshot_and_clear_dirty(MemoryRegion *mr, + hwaddr addr, + hwaddr size, + unsigned client); + +/** + * memory_region_snapshot_get_dirty: Check whether a range of bytes is dirty + * in the specified dirty bitmap snapshot. + * + * @mr: the memory region being queried. + * @snap: the dirty bitmap snapshot + * @addr: the address (relative to the start of the region) being queried. + * @size: the size of the range being queried. + */ +bool memory_region_snapshot_get_dirty(MemoryRegion *mr, + DirtyBitmapSnapshot *snap, + hwaddr addr, hwaddr size); + /** * memory_region_sync_dirty_bitmap: Synchronize a region's dirty bitmap with * any external TLBs (e.g. kvm) diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index 29647303b0..571188cdec 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -343,6 +343,13 @@ bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start, ram_addr_t length, unsigned client); +DirtyBitmapSnapshot *cpu_physical_memory_snapshot_and_clear_dirty + (ram_addr_t start, ram_addr_t length, unsigned client); + +bool cpu_physical_memory_snapshot_get_dirty(DirtyBitmapSnapshot *snap, + ram_addr_t start, + ram_addr_t length); + static inline void cpu_physical_memory_clear_dirty_range(ram_addr_t start, ram_addr_t length) { diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h index e95f28cfec..f08d327aec 100644 --- a/include/qemu/typedefs.h +++ b/include/qemu/typedefs.h @@ -23,6 +23,7 @@ typedef struct CPUAddressSpace CPUAddressSpace; typedef struct CPUState CPUState; typedef struct DeviceListener DeviceListener; typedef struct DeviceState DeviceState; +typedef struct DirtyBitmapSnapshot DirtyBitmapSnapshot; typedef struct DisplayChangeListener DisplayChangeListener; typedef struct DisplayState DisplayState; typedef struct DisplaySurface DisplaySurface; diff --git a/memory.c b/memory.c index 4c95aaf39c..8a0648551f 100644 --- a/memory.c +++ b/memory.c @@ -1716,6 +1716,23 @@ bool memory_region_test_and_clear_dirty(MemoryRegion *mr, hwaddr addr, memory_region_get_ram_addr(mr) + addr, size, client); } +DirtyBitmapSnapshot *memory_region_snapshot_and_clear_dirty(MemoryRegion *mr, + hwaddr addr, + hwaddr size, + unsigned client) +{ + assert(mr->ram_block); + return cpu_physical_memory_snapshot_and_clear_dirty( + memory_region_get_ram_addr(mr) + addr, size, client); +} + +bool memory_region_snapshot_get_dirty(MemoryRegion *mr, DirtyBitmapSnapshot *snap, + hwaddr addr, hwaddr size) +{ + assert(mr->ram_block); + return cpu_physical_memory_snapshot_get_dirty(snap, + memory_region_get_ram_addr(mr) + addr, size); +} void memory_region_sync_dirty_bitmap(MemoryRegion *mr) {
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