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* [Qemu-devel] [RFC] Memory API
@ 2011-05-18 13:12 Avi Kivity
  2011-05-18 14:05 ` Jan Kiszka
                   ` (5 more replies)
  0 siblings, 6 replies; 187+ messages in thread
From: Avi Kivity @ 2011-05-18 13:12 UTC (permalink / raw)
  To: qemu-devel

The current memory APIs (cpu_register_io_memory, 
cpu_register_physical_memory) suffer from a number of drawbacks:

- lack of centralized bookkeeping
    - a cpu_register_physical_memory() that overlaps an existing region 
will overwrite the preexisting region; but a following 
cpu_unregister_physical_memory() will not restore things to status quo ante.
    - coalescing and dirty logging are all cleared on unregistering, so 
the client has to re-issue them when re-registering
- lots of opaques
- no nesting
    - if a region has multiple subregions that need different handling 
(different callbacks, RAM interspersed with MMIO) then client code has 
to deal with that manually
    - we can't interpose code between a device and global memory handling

To fix that, I propose an new API to replace the existing one:


#ifndef MEMORY_H
#define MEMORY_H

typedef struct MemoryRegionOps MemoryRegionOps;
typedef struct MemoryRegion MemoryRegion;

typedef uint32_t (*MemoryReadFunc)(MemoryRegion *mr, target_phys_addr_t 
addr);
typedef void (*MemoryWriteFunc)(MemoryRegion *mr, target_phys_addr_t addr,
                                 uint32_t data);

struct MemoryRegionOps {
     MemoryReadFunc readb, readw, readl;
     MemoryWriteFunc writeb, writew, writel;
};

struct MemoryRegion {
     const MemoryRegionOps *ops;
     target_phys_addr_t size;
     target_phys_addr_t addr;
};

void memory_region_init(MemoryRegion *mr,
                         target_phys_addr_t size);
void memory_region_init_io(MemoryRegion *mr,
                            const MemoryRegionOps *ops,
                            target_phys_addr_t size);
void memory_region_init_ram(MemoryRegion *mr,
                             target_phys_addr_t size);
void memory_region_init_ram_ptr(MemoryRegion *mr,
                                 target_phys_addr_t size,
                                 void *ptr);
void memory_region_destroy(MemoryRegion *mr);
void memory_region_set_offset(MemoryRegion *mr, target_phys_addr_t offset);
void memory_region_set_log(MemoryRegion *mr, bool log);
void memory_region_clear_coalescing(MemoryRegion *mr);
void memory_region_add_coalescing(MemoryRegion *mr,
                                   target_phys_addr_t offset,
                                   target_phys_addr_t size);

void memory_region_add_subregion(MemoryRegion *mr,
                                  target_phys_addr_t offset,
                                  MemoryRegion *subregion);
void memory_region_del_subregion(MemoryRegion *mr,
                                  target_phys_addr_t offset,
                                  MemoryRegion *subregion);

void cpu_register_memory_region(MemoryRegion *mr, target_phys_addr_t addr);
void cpu_unregister_memory_region(MemoryRegion *mr);

#endif

The API is nested: you can define, say, a PCI BAR containing RAM and 
MMIO, and give it to the PCI subsystem.  PCI can then enable/disable the 
BAR and move it to different addresses without calling any callbacks; 
the client code can enable or disable logging or coalescing without 
caring if the BAR is mapped or not.  For example:

   MemoryRegion mr, mr_mmio, mr_ram;

   memory_region_init(&mr);
   memory_region_init_io(&mr_mmio, &mmio_ops, 0x1000);
   memory_region_init_ram(&mr_ram, 0x100000);
   memory_region_add_subregion(&mr, 0, &mr_ram);
   memory_region_add_subregion(&mr, 0x10000, &mr_io);
   memory_region_add_coalescing(&mr_ram, 0, 0x100000);
   pci_register_bar(&pci_dev, 0, &mr);

at this point the PCI subsystem knows everything about the BAR and can 
enable or disable it, or move it around, without further help from the 
device code.  On the other hand, the device code can change logging or 
coalescing, or even change the structure of the region, without caring 
about whether the region is currently registered or not.

If we can agree on the API, then I think the way forward is to implement 
it in terms of the old API, change over all devices, then fold the old 
API into the new one.

-- 
error compiling committee.c: too many arguments to function

^ permalink raw reply	[flat|nested] 187+ messages in thread

end of thread, other threads:[~2011-05-23 22:29 UTC | newest]

Thread overview: 187+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-05-18 13:12 [Qemu-devel] [RFC] Memory API Avi Kivity
2011-05-18 14:05 ` Jan Kiszka
2011-05-18 14:36   ` Avi Kivity
2011-05-18 15:11     ` Jan Kiszka
2011-05-18 15:17       ` Peter Maydell
2011-05-18 15:30         ` Jan Kiszka
2011-05-18 19:10           ` Anthony Liguori
2011-05-18 19:27             ` Jan Kiszka
2011-05-18 19:34               ` Anthony Liguori
2011-05-18 20:02                 ` Alex Williamson
2011-05-18 20:11                   ` Jan Kiszka
2011-05-18 20:13                     ` Alex Williamson
2011-05-18 20:07                 ` Jan Kiszka
2011-05-18 20:41                   ` Anthony Liguori
2011-05-19  8:26               ` Gleb Natapov
2011-05-19  8:30                 ` Jan Kiszka
2011-05-19  8:44                   ` Avi Kivity
2011-05-19 13:59                     ` Anthony Liguori
2011-05-19 13:52                   ` Anthony Liguori
2011-05-19 13:56                     ` Avi Kivity
2011-05-19 13:57                     ` Jan Kiszka
2011-05-19 14:04                       ` Anthony Liguori
2011-05-19 14:06                         ` Jan Kiszka
2011-05-19 14:11                         ` Avi Kivity
2011-05-19 18:18                           ` Anthony Liguori
2011-05-19 18:50                             ` Jan Kiszka
2011-05-19 19:02                               ` Anthony Liguori
2011-05-19 19:10                                 ` Jan Kiszka
2011-05-20  9:15                             ` Avi Kivity
2011-05-20 17:30                   ` Blue Swirl
2011-05-22  7:23                     ` Avi Kivity
2011-05-19  6:31             ` Jan Kiszka
2011-05-19 13:23               ` Anthony Liguori
2011-05-19 13:25                 ` Jan Kiszka
2011-05-19 13:26                 ` Avi Kivity
2011-05-19 13:35                   ` Anthony Liguori
2011-05-19 13:36                     ` Jan Kiszka
2011-05-19 13:43                       ` Avi Kivity
2011-05-19 13:39                     ` Avi Kivity
2011-05-19  8:09             ` Avi Kivity
2011-05-18 15:23       ` Avi Kivity
2011-05-18 15:36         ` Jan Kiszka
2011-05-18 15:42           ` Avi Kivity
2011-05-18 16:00             ` Jan Kiszka
2011-05-18 16:14               ` Avi Kivity
2011-05-18 16:39                 ` Jan Kiszka
2011-05-18 16:47                   ` Avi Kivity
2011-05-18 17:07                     ` Jan Kiszka
2011-05-18 17:15                       ` Avi Kivity
2011-05-18 17:40                         ` Jan Kiszka
2011-05-18 20:13                     ` Richard Henderson
2011-05-19  8:04                       ` Avi Kivity
2011-05-19  9:08             ` Gleb Natapov
2011-05-19  9:10               ` Avi Kivity
2011-05-19  9:14                 ` Gleb Natapov
2011-05-19 11:44                   ` Avi Kivity
2011-05-19 11:54                     ` Gleb Natapov
2011-05-19 11:57                       ` Jan Kiszka
2011-05-19 11:58                         ` Gleb Natapov
2011-05-19 12:02                           ` Avi Kivity
2011-05-19 12:21                             ` Gleb Natapov
2011-05-19 12:02                           ` Jan Kiszka
2011-05-19 11:57                       ` Avi Kivity
2011-05-19 12:20                         ` Jan Kiszka
2011-05-19 12:50                           ` Avi Kivity
2011-05-19 12:58                             ` Jan Kiszka
2011-05-19 13:00                               ` Avi Kivity
2011-05-19 13:03                                 ` Jan Kiszka
2011-05-19 13:07                                   ` Avi Kivity
2011-05-19 13:26                                     ` Jan Kiszka
2011-05-19 13:30                                       ` Avi Kivity
2011-05-19 13:43                                         ` Jan Kiszka
2011-05-19 13:47                                           ` Avi Kivity
2011-05-19 13:49                                         ` Anthony Liguori
2011-05-19 13:53                                           ` Avi Kivity
2011-05-19 14:15                                             ` Anthony Liguori
2011-05-19 14:20                                               ` Jan Kiszka
2011-05-19 14:25                                                 ` Anthony Liguori
2011-05-19 14:28                                                   ` Jan Kiszka
2011-05-19 14:31                                                     ` Avi Kivity
2011-05-19 14:37                                                     ` Anthony Liguori
2011-05-19 14:40                                                       ` Avi Kivity
2011-05-19 16:17                                                         ` Gleb Natapov
2011-05-19 16:25                                                           ` Jan Kiszka
2011-05-19 16:28                                                             ` Gleb Natapov
2011-05-19 16:30                                                               ` Jan Kiszka
2011-05-19 16:36                                                                 ` Anthony Liguori
2011-05-19 16:49                                                                   ` Jan Kiszka
2011-05-19 17:12                                                                     ` Gleb Natapov
2011-05-19 18:11                                                                       ` Jan Kiszka
2011-05-20  8:58                                                                     ` Avi Kivity
2011-05-20  8:56                                                                   ` Avi Kivity
2011-05-20 14:51                                                                     ` Anthony Liguori
2011-05-20 16:43                                                                       ` Olivier Galibert
2011-05-20 17:32                                                                         ` Anthony Liguori
2011-05-22  7:36                                                                       ` Avi Kivity
2011-05-19 16:43                                                                 ` Gleb Natapov
2011-05-19 16:51                                                                   ` Jan Kiszka
2011-05-19 16:27                                                         ` Gleb Natapov
2011-05-20  8:59                                                           ` Avi Kivity
2011-05-20 11:57                                                             ` Gleb Natapov
2011-05-22  7:37                                                               ` Avi Kivity
2011-05-22  8:06                                                                 ` Gleb Natapov
2011-05-22  8:09                                                                   ` Avi Kivity
2011-05-22  8:59                                                                     ` Gleb Natapov
2011-05-22 12:26                                                                       ` Avi Kivity
2011-05-19 16:32                                                         ` Anthony Liguori
2011-05-19 16:35                                                           ` Jan Kiszka
2011-05-19 16:38                                                             ` Anthony Liguori
2011-05-19 16:50                                                               ` Jan Kiszka
2011-05-20  9:03                                                               ` Avi Kivity
2011-05-20  9:01                                                           ` Avi Kivity
2011-05-20 15:33                                                             ` Anthony Liguori
2011-05-20 15:59                                                               ` Jan Kiszka
2011-05-22  7:38                                                                 ` Avi Kivity
2011-05-22 15:42                                                                   ` Anthony Liguori
2011-05-19 14:21                                               ` Avi Kivity
2011-05-19 13:44                 ` Anthony Liguori
2011-05-19 13:47                   ` Jan Kiszka
2011-05-19 13:50                     ` Anthony Liguori
2011-05-19 13:55                       ` Jan Kiszka
2011-05-19 13:55                       ` Avi Kivity
2011-05-19 18:06                         ` Anthony Liguori
2011-05-19 18:21                           ` Jan Kiszka
2011-05-19 13:49                   ` Avi Kivity
2011-05-19  9:24               ` Edgar E. Iglesias
2011-05-19 14:49                 ` Peter Maydell
2011-05-18 16:33         ` Anthony Liguori
2011-05-18 16:41           ` Avi Kivity
2011-05-18 17:04             ` Anthony Liguori
2011-05-18 17:13               ` Avi Kivity
2011-05-18 16:42           ` Jan Kiszka
2011-05-18 17:05             ` Avi Kivity
2011-05-18 15:14   ` Anthony Liguori
2011-05-18 15:26     ` Avi Kivity
2011-05-18 16:21       ` Avi Kivity
2011-05-18 16:42         ` Jan Kiszka
2011-05-18 16:49           ` Avi Kivity
2011-05-18 17:11             ` Anthony Liguori
2011-05-18 17:38               ` Jan Kiszka
2011-05-18 15:08 ` Anthony Liguori
2011-05-18 15:37   ` Avi Kivity
2011-05-18 19:36     ` Jan Kiszka
2011-05-18 15:47   ` Stefan Weil
2011-05-18 16:06     ` Avi Kivity
2011-05-18 16:51       ` Richard Henderson
2011-05-18 16:53         ` Avi Kivity
2011-05-18 17:03           ` Richard Henderson
2011-05-18 15:58 ` Avi Kivity
2011-05-18 16:26 ` Richard Henderson
2011-05-18 16:37   ` Avi Kivity
2011-05-18 17:17 ` Avi Kivity
2011-05-18 19:40 ` Jan Kiszka
2011-05-19  8:06   ` Avi Kivity
2011-05-19  8:08     ` Jan Kiszka
2011-05-19  8:13       ` Avi Kivity
2011-05-19  8:25         ` Jan Kiszka
2011-05-19  8:43           ` Avi Kivity
2011-05-19  9:24             ` Jan Kiszka
2011-05-19 11:58               ` Avi Kivity
2011-05-19 13:36   ` Anthony Liguori
2011-05-19 13:37     ` Jan Kiszka
2011-05-19 13:41       ` Avi Kivity
2011-05-19 17:39       ` Gleb Natapov
2011-05-19 18:03         ` Anthony Liguori
2011-05-19 18:28           ` Gleb Natapov
2011-05-19 18:33             ` Anthony Liguori
2011-05-19 18:11         ` Jan Kiszka
2011-05-19 18:22           ` Gleb Natapov
2011-05-19 18:27             ` Jan Kiszka
2011-05-19 18:40               ` Gleb Natapov
2011-05-19 18:45                 ` Jan Kiszka
2011-05-19 18:50                   ` Gleb Natapov
2011-05-19 18:55                     ` Jan Kiszka
2011-05-19 19:02                       ` Jan Kiszka
2011-05-20  7:23                       ` Gleb Natapov
2011-05-20  7:40                         ` Jan Kiszka
2011-05-20 11:25                           ` Gleb Natapov
2011-05-22  7:50                             ` Avi Kivity
2011-05-22  8:41                               ` Gleb Natapov
2011-05-22 10:53                                 ` Jan Kiszka
2011-05-22 11:29                                   ` Avi Kivity
2011-05-23  8:45                                     ` Gleb Natapov
2011-05-23 22:29                                 ` Jamie Lokier
2011-05-20  9:10             ` Avi Kivity
2011-05-20 12:08               ` Gleb Natapov
2011-05-22  7:56                 ` Avi Kivity

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