[Qemu-devel] [PULL 2/4] dump: introduce GuestPhysBlockList

[Luiz Capitulino <lcapitulino@redhat.com>]

From: Laszlo Ersek <lersek@redhat.com>

The vmcore must use physical addresses that are visible to the guest, not
addresses that point into linear RAMBlocks. As first step, introduce the
list type into which we'll collect the physical mappings in effect at the
time of the dump.

Related RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=981582

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 dump.c                          | 31 +++++++++++++++++++------------
 include/sysemu/memory_mapping.h | 22 ++++++++++++++++++++++
 memory_mapping.c                | 17 +++++++++++++++++
 3 files changed, 58 insertions(+), 12 deletions(-)

diff --git a/dump.c b/dump.c
index 9a2f939..716fb1d 100644
--- a/dump.c
+++ b/dump.c
@@ -59,6 +59,7 @@ static uint64_t cpu_convert_to_target64(uint64_t val, int endian)
 }
 
 typedef struct DumpState {
+    GuestPhysBlockList guest_phys_blocks;
     ArchDumpInfo dump_info;
     MemoryMappingList list;
     uint16_t phdr_num;
@@ -81,6 +82,7 @@ static int dump_cleanup(DumpState *s)
 {
     int ret = 0;
 
+    guest_phys_blocks_free(&s->guest_phys_blocks);
     memory_mapping_list_free(&s->list);
     if (s->fd != -1) {
         close(s->fd);
@@ -728,31 +730,34 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
         s->resume = false;
     }
 
+    /* If we use KVM, we should synchronize the registers before we get dump
+     * info or physmap info.
+     */
+    cpu_synchronize_all_states();
+    nr_cpus = 0;
+    for (cpu = first_cpu; cpu != NULL; cpu = cpu->next_cpu) {
+        nr_cpus++;
+    }
+
     s->errp = errp;
     s->fd = fd;
     s->has_filter = has_filter;
     s->begin = begin;
     s->length = length;
+
+    guest_phys_blocks_init(&s->guest_phys_blocks);
+    /* FILL LIST */
+
     s->start = get_start_block(s);
     if (s->start == -1) {
         error_set(errp, QERR_INVALID_PARAMETER, "begin");
         goto cleanup;
     }
 
-    /*
-     * get dump info: endian, class and architecture.
+    /* get dump info: endian, class and architecture.
      * If the target architecture is not supported, cpu_get_dump_info() will
      * return -1.
-     *
-     * If we use KVM, we should synchronize the registers before we get dump
-     * info.
      */
-    cpu_synchronize_all_states();
-    nr_cpus = 0;
-    for (cpu = first_cpu; cpu != NULL; cpu = cpu->next_cpu) {
-        nr_cpus++;
-    }
-
     ret = cpu_get_dump_info(&s->dump_info);
     if (ret < 0) {
         error_set(errp, QERR_UNSUPPORTED);
@@ -827,6 +832,8 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
     return 0;
 
 cleanup:
+    guest_phys_blocks_free(&s->guest_phys_blocks);
+
     if (s->resume) {
         vm_start();
     }
@@ -874,7 +881,7 @@ void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin,
         return;
     }
 
-    s = g_malloc(sizeof(DumpState));
+    s = g_malloc0(sizeof(DumpState));
 
     ret = dump_init(s, fd, paging, has_begin, begin, length, errp);
     if (ret < 0) {
diff --git a/include/sysemu/memory_mapping.h b/include/sysemu/memory_mapping.h
index 6dfb68d..d2d06cd 100644
--- a/include/sysemu/memory_mapping.h
+++ b/include/sysemu/memory_mapping.h
@@ -17,6 +17,25 @@
 #include "qemu/queue.h"
 #include "qemu/typedefs.h"
 
+typedef struct GuestPhysBlock {
+    /* visible to guest, reflects PCI hole, etc */
+    hwaddr target_start;
+
+    /* implies size */
+    hwaddr target_end;
+
+    /* points into host memory */
+    uint8_t *host_addr;
+
+    QTAILQ_ENTRY(GuestPhysBlock) next;
+} GuestPhysBlock;
+
+/* point-in-time snapshot of guest-visible physical mappings */
+typedef struct GuestPhysBlockList {
+    unsigned num;
+    QTAILQ_HEAD(GuestPhysBlockHead, GuestPhysBlock) head;
+} GuestPhysBlockList;
+
 /* The physical and virtual address in the memory mapping are contiguous. */
 typedef struct MemoryMapping {
     hwaddr phys_addr;
@@ -45,6 +64,9 @@ void memory_mapping_list_free(MemoryMappingList *list);
 
 void memory_mapping_list_init(MemoryMappingList *list);
 
+void guest_phys_blocks_free(GuestPhysBlockList *list);
+void guest_phys_blocks_init(GuestPhysBlockList *list);
+
 void qemu_get_guest_memory_mapping(MemoryMappingList *list, Error **errp);
 
 /* get guest's memory mapping without do paging(virtual address is 0). */
diff --git a/memory_mapping.c b/memory_mapping.c
index 515a984..c70505b 100644
--- a/memory_mapping.c
+++ b/memory_mapping.c
@@ -165,6 +165,23 @@ void memory_mapping_list_init(MemoryMappingList *list)
     QTAILQ_INIT(&list->head);
 }
 
+void guest_phys_blocks_free(GuestPhysBlockList *list)
+{
+    GuestPhysBlock *p, *q;
+
+    QTAILQ_FOREACH_SAFE(p, &list->head, next, q) {
+        QTAILQ_REMOVE(&list->head, p, next);
+        g_free(p);
+    }
+    list->num = 0;
+}
+
+void guest_phys_blocks_init(GuestPhysBlockList *list)
+{
+    list->num = 0;
+    QTAILQ_INIT(&list->head);
+}
+
 static CPUState *find_paging_enabled_cpu(CPUState *start_cpu)
 {
     CPUState *cpu;
-- 
1.8.1.4