From 25c893037b89ddd4e42927a2a9b524dbbc0c34a3 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 23 May 2023 20:30:36 +0200 Subject: [PATCH] virtio-mem: Simplify bitmap handling and virtio_mem_set_block_state() Let's separate plug and unplug handling to prepare for future changes and make the code a bit easier to read -- working on block states (plugged/unplugged) instead of on a bitmap. Cc: "Michael S. Tsirkin" Cc: Gavin Shan Signed-off-by: David Hildenbrand Message-Id: <20230523183036.517957-1-david@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-mem.c | 116 ++++++++++++++++++++++++++++--------------------- 1 file changed, 66 insertions(+), 50 deletions(-) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 12ea58d5ad..ec0ae32589 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -398,33 +398,46 @@ static void virtio_mem_notify_unplug_all(VirtIOMEM *vmem) } } -static bool virtio_mem_test_bitmap(const VirtIOMEM *vmem, uint64_t start_gpa, - uint64_t size, bool plugged) +static bool virtio_mem_is_range_plugged(const VirtIOMEM *vmem, + uint64_t start_gpa, uint64_t size) { const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size; const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1; unsigned long found_bit; /* We fake a shorter bitmap to avoid searching too far. */ - if (plugged) { - found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit); - } else { - found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit); - } + found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit); return found_bit > last_bit; } -static void virtio_mem_set_bitmap(VirtIOMEM *vmem, uint64_t start_gpa, - uint64_t size, bool plugged) +static bool virtio_mem_is_range_unplugged(const VirtIOMEM *vmem, + uint64_t start_gpa, uint64_t size) +{ + const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size; + const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1; + unsigned long found_bit; + + /* We fake a shorter bitmap to avoid searching too far. */ + found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit); + return found_bit > last_bit; +} + +static void virtio_mem_set_range_plugged(VirtIOMEM *vmem, uint64_t start_gpa, + uint64_t size) { const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size; const unsigned long nbits = size / vmem->block_size; - if (plugged) { - bitmap_set(vmem->bitmap, bit, nbits); - } else { - bitmap_clear(vmem->bitmap, bit, nbits); - } + bitmap_set(vmem->bitmap, bit, nbits); +} + +static void virtio_mem_set_range_unplugged(VirtIOMEM *vmem, uint64_t start_gpa, + uint64_t size) +{ + const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size; + const unsigned long nbits = size / vmem->block_size; + + bitmap_clear(vmem->bitmap, bit, nbits); } static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem, @@ -474,6 +487,7 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, { const uint64_t offset = start_gpa - vmem->addr; RAMBlock *rb = vmem->memdev->mr.ram_block; + int ret = 0; if (virtio_mem_is_busy()) { return -EBUSY; @@ -484,42 +498,43 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, return -EBUSY; } virtio_mem_notify_unplug(vmem, offset, size); - } else { - int ret = 0; - - if (vmem->prealloc) { - void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset; - int fd = memory_region_get_fd(&vmem->memdev->mr); - Error *local_err = NULL; - - qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err); - if (local_err) { - static bool warned; - - /* - * Warn only once, we don't want to fill the log with these - * warnings. - */ - if (!warned) { - warn_report_err(local_err); - warned = true; - } else { - error_free(local_err); - } - ret = -EBUSY; + virtio_mem_set_range_unplugged(vmem, start_gpa, size); + return 0; + } + + if (vmem->prealloc) { + void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset; + int fd = memory_region_get_fd(&vmem->memdev->mr); + Error *local_err = NULL; + + qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err); + if (local_err) { + static bool warned; + + /* + * Warn only once, we don't want to fill the log with these + * warnings. + */ + if (!warned) { + warn_report_err(local_err); + warned = true; + } else { + error_free(local_err); } + ret = -EBUSY; } - if (!ret) { - ret = virtio_mem_notify_plug(vmem, offset, size); - } + } - if (ret) { - /* Could be preallocation or a notifier populated memory. */ - ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); - return -EBUSY; - } + if (!ret) { + ret = virtio_mem_notify_plug(vmem, offset, size); } - virtio_mem_set_bitmap(vmem, start_gpa, size, plug); + if (ret) { + /* Could be preallocation or a notifier populated memory. */ + ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); + return -EBUSY; + } + + virtio_mem_set_range_plugged(vmem, start_gpa, size); return 0; } @@ -538,7 +553,8 @@ static int virtio_mem_state_change_request(VirtIOMEM *vmem, uint64_t gpa, } /* test if really all blocks are in the opposite state */ - if (!virtio_mem_test_bitmap(vmem, gpa, size, !plug)) { + if ((plug && !virtio_mem_is_range_unplugged(vmem, gpa, size)) || + (!plug && !virtio_mem_is_range_plugged(vmem, gpa, size))) { return VIRTIO_MEM_RESP_ERROR; } @@ -651,9 +667,9 @@ static void virtio_mem_state_request(VirtIOMEM *vmem, VirtQueueElement *elem, return; } - if (virtio_mem_test_bitmap(vmem, gpa, size, true)) { + if (virtio_mem_is_range_plugged(vmem, gpa, size)) { resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED); - } else if (virtio_mem_test_bitmap(vmem, gpa, size, false)) { + } else if (virtio_mem_is_range_unplugged(vmem, gpa, size)) { resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED); } else { resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED); @@ -1372,7 +1388,7 @@ static bool virtio_mem_rdm_is_populated(const RamDiscardManager *rdm, return false; } - return virtio_mem_test_bitmap(vmem, start_gpa, end_gpa - start_gpa, true); + return virtio_mem_is_range_plugged(vmem, start_gpa, end_gpa - start_gpa); } struct VirtIOMEMReplayData { -- 2.11.4.GIT