mirror of
https://github.com/qemu/qemu.git
synced 2025-10-31 12:07:31 +00:00
185ecf40e3
The data plane thread needs to map guest physical addresses to host pointers. Normally this is done with cpu_physical_memory_map() but the function assumes the global mutex is held. The data plane thread does not touch the global mutex and therefore needs a thread-safe memory mapping mechanism. Hostmem registers a MemoryListener similar to how vhost collects and pushes memory region information into the kernel. There is a fine-grained lock on the regions list which is held during lookup and when installing a new regions list. When the physical memory map changes the MemoryListener callbacks are invoked. They build up a new list of memory regions which is finally installed when the list has been completed. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
/*
|
|
* Thread-safe guest to host memory mapping
|
|
*
|
|
* Copyright 2012 Red Hat, Inc. and/or its affiliates
|
|
*
|
|
* Authors:
|
|
* Stefan Hajnoczi <stefanha@redhat.com>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*
|
|
*/
|
|
|
|
#ifndef HOSTMEM_H
|
|
#define HOSTMEM_H
|
|
|
|
#include "exec/memory.h"
|
|
#include "qemu/thread.h"
|
|
|
|
typedef struct {
|
|
void *host_addr;
|
|
hwaddr guest_addr;
|
|
uint64_t size;
|
|
bool readonly;
|
|
} HostMemRegion;
|
|
|
|
typedef struct {
|
|
/* The listener is invoked when regions change and a new list of regions is
|
|
* built up completely before they are installed.
|
|
*/
|
|
MemoryListener listener;
|
|
HostMemRegion *new_regions;
|
|
size_t num_new_regions;
|
|
|
|
/* Current regions are accessed from multiple threads either to lookup
|
|
* addresses or to install a new list of regions. The lock protects the
|
|
* pointer and the regions.
|
|
*/
|
|
QemuMutex current_regions_lock;
|
|
HostMemRegion *current_regions;
|
|
size_t num_current_regions;
|
|
} HostMem;
|
|
|
|
void hostmem_init(HostMem *hostmem);
|
|
void hostmem_finalize(HostMem *hostmem);
|
|
|
|
/**
|
|
* Map a guest physical address to a pointer
|
|
*
|
|
* Note that there is map/unmap mechanism here. The caller must ensure that
|
|
* mapped memory is no longer used across events like hot memory unplug. This
|
|
* can be done with other mechanisms like bdrv_drain_all() that quiesce
|
|
* in-flight I/O.
|
|
*/
|
|
void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write);
|
|
|
|
#endif /* HOSTMEM_H */
|