Re: [Qemu-devel] [RFC][PATCH 1/5 v2] Add API to create memory mapping list

[Jan Kiszka]

On 2011-12-09 09:06, Wen Congyang wrote:
> The memory mapping list stores virtual address and physical address mapping.
> The folloing patch will use this information to create PT_LOAD in the vmcore.
> 
> Signed-off-by: Wen Congyang <address@hidden>
> ---
>  Makefile.target  |    1 +
>  memory_mapping.c |  130 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  memory_mapping.h |   29 ++++++++++++
>  3 files changed, 160 insertions(+), 0 deletions(-)
>  create mode 100644 memory_mapping.c
>  create mode 100644 memory_mapping.h
> 
> diff --git a/Makefile.target b/Makefile.target
> index a111521..778f514 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -205,6 +205,7 @@ obj-$(CONFIG_REALLY_VIRTFS) += 9pfs/virtio-9p-device.o
>  obj-$(CONFIG_KVM) += kvm.o kvm-all.o
>  obj-$(CONFIG_NO_KVM) += kvm-stub.o
>  obj-y += memory.o
> +obj-y += memory_mapping.o
>  LIBS+=-lz
>  
>  QEMU_CFLAGS += $(VNC_TLS_CFLAGS)
> diff --git a/memory_mapping.c b/memory_mapping.c
> new file mode 100644
> index 0000000..d83b7d7
> --- /dev/null
> +++ b/memory_mapping.c
> @@ -0,0 +1,130 @@
> +/*
> + * QEMU memory mapping
> + *
> + * Copyright Fujitsu, Corp. 2011
> + *
> + * Authors:
> + *     Wen Congyang <address@hidden>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "cpu.h"
> +#include "cpu-all.h"
> +#include "memory_mapping.h"
> +
> +static MemoryMapping *last_mapping;
> +
> +static void create_new_memory_mapping(MemoryMappingList *list,
> +                                      target_phys_addr_t phys_addr,
> +                                      target_phys_addr_t virt_addr,
> +                                      ram_addr_t length)
> +{
> +    MemoryMapping *memory_mapping, *p;
> +
> +    memory_mapping = g_malloc(sizeof(MemoryMapping));
> +    memory_mapping->phys_addr = phys_addr;
> +    memory_mapping->virt_addr = virt_addr;
> +    memory_mapping->length = length;
> +    last_mapping = memory_mapping;
> +    list->num++;
> +    QTAILQ_FOREACH(p, &list->head, next) {
> +        if (p->phys_addr >= memory_mapping->phys_addr) {
> +            QTAILQ_INSERT_BEFORE(p, memory_mapping, next);
> +            return;
> +        }
> +    }
> +    QTAILQ_INSERT_TAIL(&list->head, memory_mapping, next);
> +    return;
> +}
> +
> +void create_new_memory_mapping_head(MemoryMappingList *list,
> +                                    target_phys_addr_t phys_addr,
> +                                    target_phys_addr_t virt_addr,
> +                                    ram_addr_t length)
> +{
> +    MemoryMapping *memory_mapping;
> +
> +    memory_mapping = g_malloc(sizeof(MemoryMapping));
> +    memory_mapping->phys_addr = phys_addr;
> +    memory_mapping->virt_addr = virt_addr;
> +    memory_mapping->length = length;
> +    last_mapping = memory_mapping;
> +    list->num++;
> +    QTAILQ_INSERT_HEAD(&list->head, memory_mapping, next);
> +    return;
> +}

Isn't create_new_memory_mapping_head just a special case of
create_new_memory_mapping? And can't add_to_memory_mapping be used or
extended so that create_new_memory_mapping_head becomes obsolete?
Documenting the API would help at least me understanding the different
semantics.

> +
> +void add_to_memory_mapping(MemoryMappingList *list,
> +                           target_phys_addr_t phys_addr,
> +                           target_phys_addr_t virt_addr,
> +                           ram_addr_t length)
> +{
> +    MemoryMapping *memory_mapping;
> +
> +    if (QTAILQ_EMPTY(&list->head)) {
> +        create_new_memory_mapping(list, phys_addr, virt_addr, length);
> +        return;
> +    }
> +
> +    if (last_mapping) {
> +        if ((phys_addr == (last_mapping->phys_addr + last_mapping->length)) 
> &&
> +            (virt_addr == (last_mapping->virt_addr + last_mapping->length))) 
> {
> +            last_mapping->length += length;
> +            return;
> +        }
> +    }
> +
> +    QTAILQ_FOREACH(memory_mapping, &list->head, next) {
> +        last_mapping = memory_mapping;
> +        if ((phys_addr == (last_mapping->phys_addr + last_mapping->length)) 
> &&
> +            (virt_addr == (last_mapping->virt_addr + last_mapping->length))) 
> {
> +            last_mapping->length += length;
> +            return;
> +        }
> +
> +        if (!(phys_addr >= (last_mapping->phys_addr)) ||
> +            !(phys_addr < (last_mapping->phys_addr + last_mapping->length))) 
> {
> +            /* last_mapping does not contain this region */
> +            continue;
> +        }
> +        if (!(virt_addr >= (last_mapping->virt_addr)) ||
> +            !(virt_addr < (last_mapping->virt_addr + last_mapping->length))) 
> {
> +            /* last_mapping does not contain this region */
> +            continue;
> +        }
> +        if ((virt_addr - last_mapping->virt_addr) !=
> +            (phys_addr - last_mapping->phys_addr)) {
> +            /*
> +             * last_mapping contains this region, but we should create 
> another
> +             * mapping region.
> +             */
> +            break;
> +        }
> +
> +        /* merge this region into last_mapping */
> +        if ((virt_addr + length) >
> +            (last_mapping->virt_addr + last_mapping->length)) {
> +            last_mapping->length = virt_addr + length - 
> last_mapping->virt_addr;
> +        }
> +        return;
> +    }
> +
> +    /* this region can not be merged into any existed memory mapping. */
> +    create_new_memory_mapping(list, phys_addr, virt_addr, length);
> +    return;
> +}
> +
> +void free_memory_mapping_list(MemoryMappingList *list)
> +{
> +    MemoryMapping *p, *q;
> +
> +    QTAILQ_FOREACH_SAFE(p, &list->head, next, q) {
> +        QTAILQ_REMOVE(&list->head, p, next);
> +        g_free(p);

Can't last_mapping still point to this object?

> +    }
> +
> +    list->num = 0;
> +}
> diff --git a/memory_mapping.h b/memory_mapping.h
> new file mode 100644
> index 0000000..871591d
> --- /dev/null
> +++ b/memory_mapping.h
> @@ -0,0 +1,29 @@
> +#ifndef MEMORY_MAPPING_H
> +#define MEMORY_MAPPING_H
> +
> +#include "qemu-queue.h"
> +
> +typedef struct MemoryMapping {
> +    target_phys_addr_t phys_addr;
> +    target_ulong virt_addr;
> +    ram_addr_t length;
> +    QTAILQ_ENTRY(MemoryMapping) next;
> +} MemoryMapping;
> +
> +typedef struct MemoryMappingList {
> +    unsigned int num;
> +    QTAILQ_HEAD(, MemoryMapping) head;
> +} MemoryMappingList;
> +
> +void create_new_memory_mapping_head(MemoryMappingList *list,
> +                                    target_phys_addr_t phys_addr,
> +                                    target_phys_addr_t virt_addr,
> +                                    ram_addr_t length);
> +void add_to_memory_mapping(MemoryMappingList *list,
> +                           target_phys_addr_t phys_addr,
> +                           target_phys_addr_t virt_addr,
> +                           ram_addr_t length);
> +
> +void free_memory_mapping_list(MemoryMappingList *list);
> +
> +#endif

Jan

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