Commit 88c73d16 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Peter Maydell
Browse files

memory: fix usage of find_next_bit and find_next_zero_bit 



The last two arguments to these functions are the last and first bit to
check relative to the base.  The code was using incorrectly the first
bit and the number of bits.  Fix this in cpu_physical_memory_get_dirty
and cpu_physical_memory_all_dirty.  This requires a few changes in the
iteration; change the code in cpu_physical_memory_set_dirty_range to
match.

Fixes: 5b82b703
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Tested-by: default avatarLeon Alrae <leon.alrae@imgtec.com>
Tested-by: default avatarThomas Huth <thuth@redhat.com>
Message-id: 1455113505-11237-1-git-send-email-pbonzini@redhat.com
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent c9f19dff

include/exec/ram_addr.h

+36 −19
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ static inline bool cpu_physical_memory_get_dirty(ram_addr_t start, 
{

    DirtyMemoryBlocks *blocks;

    unsigned long end, page;

    unsigned long idx, offset, base;

    bool dirty = false;



    assert(client < DIRTY_MEMORY_NUM);
@@ -132,17 +133,22 @@ static inline bool cpu_physical_memory_get_dirty(ram_addr_t start, 


    blocks = atomic_rcu_read(&ram_list.dirty_memory[client]);



    idx = page / DIRTY_MEMORY_BLOCK_SIZE;

    offset = page % DIRTY_MEMORY_BLOCK_SIZE;

    base = page - offset;

    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);



        if (find_next_bit(blocks->blocks[idx], offset, num) < num) {

        unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE);

        unsigned long num = next - base;

        unsigned long found = find_next_bit(blocks->blocks[idx], num, offset);

        if (found < num) {

            dirty = true;

            break;

        }



        page += num;

        page = next;

        idx++;

        offset = 0;

        base += DIRTY_MEMORY_BLOCK_SIZE;

    }



    rcu_read_unlock();
@@ -156,6 +162,7 @@ static inline bool cpu_physical_memory_all_dirty(ram_addr_t start, 
{

    DirtyMemoryBlocks *blocks;

    unsigned long end, page;

    unsigned long idx, offset, base;

    bool dirty = true;



    assert(client < DIRTY_MEMORY_NUM);
@@ -167,17 +174,22 @@ static inline bool cpu_physical_memory_all_dirty(ram_addr_t start, 


    blocks = atomic_rcu_read(&ram_list.dirty_memory[client]);



    idx = page / DIRTY_MEMORY_BLOCK_SIZE;

    offset = page % DIRTY_MEMORY_BLOCK_SIZE;

    base = page - offset;

    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);



        if (find_next_zero_bit(blocks->blocks[idx], offset, num) < num) {

        unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE);

        unsigned long num = next - base;

        unsigned long found = find_next_zero_bit(blocks->blocks[idx], num, offset);

        if (found < num) {

            dirty = false;

            break;

        }



        page += num;

        page = next;

        idx++;

        offset = 0;

        base += DIRTY_MEMORY_BLOCK_SIZE;

    }



    rcu_read_unlock();
@@ -248,6 +260,7 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start, 
{

    DirtyMemoryBlocks *blocks[DIRTY_MEMORY_NUM];

    unsigned long end, page;

    unsigned long idx, offset, base;

    int i;



    if (!mask && !xen_enabled()) {
@@ -263,25 +276,29 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start, 
        blocks[i] = atomic_rcu_read(&ram_list.dirty_memory[i]);

    }



    idx = page / DIRTY_MEMORY_BLOCK_SIZE;

    offset = page % DIRTY_MEMORY_BLOCK_SIZE;

    base = page - offset;

    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);

        unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE);



        if (likely(mask & (1 << DIRTY_MEMORY_MIGRATION))) {

            bitmap_set_atomic(blocks[DIRTY_MEMORY_MIGRATION]->blocks[idx],

                              offset, num);

                              offset, next - page);

        }

        if (unlikely(mask & (1 << DIRTY_MEMORY_VGA))) {

            bitmap_set_atomic(blocks[DIRTY_MEMORY_VGA]->blocks[idx],

                              offset, num);

                              offset, next - page);

        }

        if (unlikely(mask & (1 << DIRTY_MEMORY_CODE))) {

            bitmap_set_atomic(blocks[DIRTY_MEMORY_CODE]->blocks[idx],

                              offset, num);

                              offset, next - page);

        }



        page += num;

        page = next;

        idx++;

        offset = 0;

        base += DIRTY_MEMORY_BLOCK_SIZE;

    }



    rcu_read_unlock();