exec: introduce MemoryRegionCache

Device models often have to perform multiple access to a single
memory region that is known in advance, but would to use "DMA-style"
functions instead of address_space_map/unmap.  This can happen
for example when the data has to undergo endianness conversion.
Introduce a new data structure to cache the result of
address_space_translate without forcing usage of a host address
like address_space_map does.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-11-22 12:04:52 +01:00
parent 715c31ec8e
commit 1f4e496e1f
4 changed files with 251 additions and 0 deletions

76
exec.c
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@ -3077,6 +3077,82 @@ void cpu_physical_memory_unmap(void *buffer, hwaddr len,
#define RCU_READ_UNLOCK(...) rcu_read_unlock()
#include "memory_ldst.inc.c"
int64_t address_space_cache_init(MemoryRegionCache *cache,
AddressSpace *as,
hwaddr addr,
hwaddr len,
bool is_write)
{
hwaddr l, xlat;
MemoryRegion *mr;
void *ptr;
assert(len > 0);
l = len;
mr = address_space_translate(as, addr, &xlat, &l, is_write);
if (!memory_access_is_direct(mr, is_write)) {
return -EINVAL;
}
l = address_space_extend_translation(as, addr, len, mr, xlat, l, is_write);
ptr = qemu_ram_ptr_length(mr->ram_block, xlat, &l);
cache->xlat = xlat;
cache->is_write = is_write;
cache->mr = mr;
cache->ptr = ptr;
cache->len = l;
memory_region_ref(cache->mr);
return l;
}
void address_space_cache_invalidate(MemoryRegionCache *cache,
hwaddr addr,
hwaddr access_len)
{
assert(cache->is_write);
invalidate_and_set_dirty(cache->mr, addr + cache->xlat, access_len);
}
void address_space_cache_destroy(MemoryRegionCache *cache)
{
if (!cache->mr) {
return;
}
if (xen_enabled()) {
xen_invalidate_map_cache_entry(cache->ptr);
}
memory_region_unref(cache->mr);
}
/* Called from RCU critical section. This function has the same
* semantics as address_space_translate, but it only works on a
* predefined range of a MemoryRegion that was mapped with
* address_space_cache_init.
*/
static inline MemoryRegion *address_space_translate_cached(
MemoryRegionCache *cache, hwaddr addr, hwaddr *xlat,
hwaddr *plen, bool is_write)
{
assert(addr < cache->len && *plen <= cache->len - addr);
*xlat = addr + cache->xlat;
return cache->mr;
}
#define ARG1_DECL MemoryRegionCache *cache
#define ARG1 cache
#define SUFFIX _cached
#define TRANSLATE(...) address_space_translate_cached(cache, __VA_ARGS__)
#define IS_DIRECT(mr, is_write) true
#define MAP_RAM(mr, ofs) (cache->ptr + (ofs - cache->xlat))
#define INVALIDATE(mr, ofs, len) ((void)0)
#define RCU_READ_LOCK() ((void)0)
#define RCU_READ_UNLOCK() ((void)0)
#include "memory_ldst.inc.c"
/* virtual memory access for debug (includes writing to ROM) */
int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
uint8_t *buf, int len, int is_write)

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@ -186,6 +186,29 @@ void address_space_stl(AddressSpace *as, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stq(AddressSpace *as, hwaddr addr, uint64_t val,
MemTxAttrs attrs, MemTxResult *result);
uint32_t lduw_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint32_t ldl_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint64_t ldq_phys_cached(MemoryRegionCache *cache, hwaddr addr);
void stl_phys_notdirty_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stw_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stl_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stq_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val);
uint32_t address_space_lduw_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_ldl_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint64_t address_space_ldq_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_notdirty_cached(MemoryRegionCache *cache, hwaddr addr,
uint32_t val, MemTxAttrs attrs, MemTxResult *result);
void address_space_stw_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stq_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val,
MemTxAttrs attrs, MemTxResult *result);
#endif
/* page related stuff */

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@ -1419,6 +1419,125 @@ void stl_be_phys(AddressSpace *as, hwaddr addr, uint32_t val);
void stq_le_phys(AddressSpace *as, hwaddr addr, uint64_t val);
void stq_be_phys(AddressSpace *as, hwaddr addr, uint64_t val);
struct MemoryRegionCache {
hwaddr xlat;
void *ptr;
hwaddr len;
MemoryRegion *mr;
bool is_write;
};
/* address_space_cache_init: prepare for repeated access to a physical
* memory region
*
* @cache: #MemoryRegionCache to be filled
* @as: #AddressSpace to be accessed
* @addr: address within that address space
* @len: length of buffer
* @is_write: indicates the transfer direction
*
* Will only work with RAM, and may map a subset of the requested range by
* returning a value that is less than @len. On failure, return a negative
* errno value.
*
* Because it only works with RAM, this function can be used for
* read-modify-write operations. In this case, is_write should be %true.
*
* Note that addresses passed to the address_space_*_cached functions
* are relative to @addr.
*/
int64_t address_space_cache_init(MemoryRegionCache *cache,
AddressSpace *as,
hwaddr addr,
hwaddr len,
bool is_write);
/**
* address_space_cache_invalidate: complete a write to a #MemoryRegionCache
*
* @cache: The #MemoryRegionCache to operate on.
* @addr: The first physical address that was written, relative to the
* address that was passed to @address_space_cache_init.
* @access_len: The number of bytes that were written starting at @addr.
*/
void address_space_cache_invalidate(MemoryRegionCache *cache,
hwaddr addr,
hwaddr access_len);
/**
* address_space_cache_destroy: free a #MemoryRegionCache
*
* @cache: The #MemoryRegionCache whose memory should be released.
*/
void address_space_cache_destroy(MemoryRegionCache *cache);
/* address_space_ld*_cached: load from a cached #MemoryRegion
* address_space_st*_cached: store into a cached #MemoryRegion
*
* These functions perform a load or store of the byte, word,
* longword or quad to the specified address. The address is
* a physical address in the AddressSpace, but it must lie within
* a #MemoryRegion that was mapped with address_space_cache_init.
*
* The _le suffixed functions treat the data as little endian;
* _be indicates big endian; no suffix indicates "same endianness
* as guest CPU".
*
* The "guest CPU endianness" accessors are deprecated for use outside
* target-* code; devices should be CPU-agnostic and use either the LE
* or the BE accessors.
*
* @cache: previously initialized #MemoryRegionCache to be accessed
* @addr: address within the address space
* @val: data value, for stores
* @attrs: memory transaction attributes
* @result: location to write the success/failure of the transaction;
* if NULL, this information is discarded
*/
uint32_t address_space_ldub_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_lduw_le_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_lduw_be_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_ldl_le_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_ldl_be_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint64_t address_space_ldq_le_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint64_t address_space_ldq_be_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stb_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stw_le_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stw_be_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_le_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_be_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stq_le_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stq_be_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val,
MemTxAttrs attrs, MemTxResult *result);
uint32_t ldub_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint32_t lduw_le_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint32_t lduw_be_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint32_t ldl_le_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint32_t ldl_be_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint64_t ldq_le_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint64_t ldq_be_phys_cached(MemoryRegionCache *cache, hwaddr addr);
void stb_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stw_le_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stw_be_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stl_le_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stl_be_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stq_le_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val);
void stq_be_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val);
/* address_space_translate: translate an address range into an address space
* into a MemoryRegion and an address range into that section. Should be
* called from an RCU critical section, to avoid that the last reference
@ -1544,6 +1663,38 @@ MemTxResult address_space_read(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
return result;
}
/**
* address_space_read_cached: read from a cached RAM region
*
* @cache: Cached region to be addressed
* @addr: address relative to the base of the RAM region
* @buf: buffer with the data transferred
* @len: length of the data transferred
*/
static inline void
address_space_read_cached(MemoryRegionCache *cache, hwaddr addr,
void *buf, int len)
{
assert(addr < cache->len && len <= cache->len - addr);
memcpy(buf, cache->ptr + addr, len);
}
/**
* address_space_write_cached: write to a cached RAM region
*
* @cache: Cached region to be addressed
* @addr: address relative to the base of the RAM region
* @buf: buffer with the data transferred
* @len: length of the data transferred
*/
static inline void
address_space_write_cached(MemoryRegionCache *cache, hwaddr addr,
void *buf, int len)
{
assert(addr < cache->len && len <= cache->len - addr);
memcpy(cache->ptr + addr, buf, len);
}
#endif
#endif

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@ -45,6 +45,7 @@ typedef struct MachineState MachineState;
typedef struct MemoryListener MemoryListener;
typedef struct MemoryMappingList MemoryMappingList;
typedef struct MemoryRegion MemoryRegion;
typedef struct MemoryRegionCache MemoryRegionCache;
typedef struct MemoryRegionSection MemoryRegionSection;
typedef struct MigrationIncomingState MigrationIncomingState;
typedef struct MigrationParams MigrationParams;