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qemu/include/exec/cpu-all.h
Mike Day 0dc3f44aca Convert ram_list to RCU 
Allow "unlocked" reads of the ram_list by using an RCU-enabled QLIST.

The ramlist mutex is kept.  call_rcu callbacks are run with the iothread
lock taken, but that may change in the future.  Writers still take the
ramlist mutex, but they no longer need to assume that the iothread lock
is taken.

Readers of the list, instead, no longer require either the iothread
or ramlist mutex, but they need to use rcu_read_lock() and
rcu_read_unlock().

One place in arch_init.c was downgrading from write side to read side
like this:

    qemu_mutex_lock_iothread()
    qemu_mutex_lock_ramlist()
    ...
    qemu_mutex_unlock_iothread()
    ...
    qemu_mutex_unlock_ramlist()

and the equivalent idiom is:

    qemu_mutex_lock_ramlist()
    rcu_read_lock()
    ...
    qemu_mutex_unlock_ramlist()
    ...
    rcu_read_unlock()

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Mike Day <ncmike@ncultra.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-16 17:31:55 +01:00

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/*
* defines common to all virtual CPUs
*
* Copyright (c) 2003 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef CPU_ALL_H
#define CPU_ALL_H
#include "qemu-common.h"
#include "exec/cpu-common.h"
#include "exec/memory.h"
#include "qemu/thread.h"
#include "qom/cpu.h"
#include "qemu/rcu.h"
/* some important defines:
*
* WORDS_ALIGNED : if defined, the host cpu can only make word aligned
* memory accesses.
*
* HOST_WORDS_BIGENDIAN : if defined, the host cpu is big endian and
* otherwise little endian.
*
* (TARGET_WORDS_ALIGNED : same for target cpu (not supported yet))
*
* TARGET_WORDS_BIGENDIAN : same for target cpu
*/
#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
#define BSWAP_NEEDED
#endif
#ifdef BSWAP_NEEDED
static inline uint16_t tswap16(uint16_t s)
{
return bswap16(s);
}
static inline uint32_t tswap32(uint32_t s)
{
return bswap32(s);
}
static inline uint64_t tswap64(uint64_t s)
{
return bswap64(s);
}
static inline void tswap16s(uint16_t *s)
{
*s = bswap16(*s);
}
static inline void tswap32s(uint32_t *s)
{
*s = bswap32(*s);
}
static inline void tswap64s(uint64_t *s)
{
*s = bswap64(*s);
}
#else
static inline uint16_t tswap16(uint16_t s)
{
return s;
}
static inline uint32_t tswap32(uint32_t s)
{
return s;
}
static inline uint64_t tswap64(uint64_t s)
{
return s;
}
static inline void tswap16s(uint16_t *s)
{
}
static inline void tswap32s(uint32_t *s)
{
}
static inline void tswap64s(uint64_t *s)
{
}
#endif
#if TARGET_LONG_SIZE == 4
#define tswapl(s) tswap32(s)
#define tswapls(s) tswap32s((uint32_t *)(s))
#define bswaptls(s) bswap32s(s)
#else
#define tswapl(s) tswap64(s)
#define tswapls(s) tswap64s((uint64_t *)(s))
#define bswaptls(s) bswap64s(s)
#endif
/* Target-endianness CPU memory access functions. These fit into the
* {ld,st}{type}{sign}{size}{endian}_p naming scheme described in bswap.h.
*/
#if defined(TARGET_WORDS_BIGENDIAN)
#define lduw_p(p) lduw_be_p(p)
#define ldsw_p(p) ldsw_be_p(p)
#define ldl_p(p) ldl_be_p(p)
#define ldq_p(p) ldq_be_p(p)
#define ldfl_p(p) ldfl_be_p(p)
#define ldfq_p(p) ldfq_be_p(p)
#define stw_p(p, v) stw_be_p(p, v)
#define stl_p(p, v) stl_be_p(p, v)
#define stq_p(p, v) stq_be_p(p, v)
#define stfl_p(p, v) stfl_be_p(p, v)
#define stfq_p(p, v) stfq_be_p(p, v)
#else
#define lduw_p(p) lduw_le_p(p)
#define ldsw_p(p) ldsw_le_p(p)
#define ldl_p(p) ldl_le_p(p)
#define ldq_p(p) ldq_le_p(p)
#define ldfl_p(p) ldfl_le_p(p)
#define ldfq_p(p) ldfq_le_p(p)
#define stw_p(p, v) stw_le_p(p, v)
#define stl_p(p, v) stl_le_p(p, v)
#define stq_p(p, v) stq_le_p(p, v)
#define stfl_p(p, v) stfl_le_p(p, v)
#define stfq_p(p, v) stfq_le_p(p, v)
#endif
/* MMU memory access macros */
#if defined(CONFIG_USER_ONLY)
#include <assert.h>
#include "exec/user/abitypes.h"
/* On some host systems the guest address space is reserved on the host.
* This allows the guest address space to be offset to a convenient location.
*/
#if defined(CONFIG_USE_GUEST_BASE)
extern unsigned long guest_base;
extern int have_guest_base;
extern unsigned long reserved_va;
#define GUEST_BASE guest_base
#define RESERVED_VA reserved_va
#else
#define GUEST_BASE 0ul
#define RESERVED_VA 0ul
#endif
#define GUEST_ADDR_MAX (RESERVED_VA ? RESERVED_VA : \
(1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
#endif
/* page related stuff */
#define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
#define TARGET_PAGE_MASK ~(TARGET_PAGE_SIZE - 1)
#define TARGET_PAGE_ALIGN(addr) (((addr) + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK)
/* ??? These should be the larger of uintptr_t and target_ulong. */
extern uintptr_t qemu_real_host_page_size;
extern uintptr_t qemu_host_page_size;
extern uintptr_t qemu_host_page_mask;
#define HOST_PAGE_ALIGN(addr) (((addr) + qemu_host_page_size - 1) & qemu_host_page_mask)
/* same as PROT_xxx */
#define PAGE_READ 0x0001
#define PAGE_WRITE 0x0002
#define PAGE_EXEC 0x0004
#define PAGE_BITS (PAGE_READ | PAGE_WRITE | PAGE_EXEC)
#define PAGE_VALID 0x0008
/* original state of the write flag (used when tracking self-modifying
code */
#define PAGE_WRITE_ORG 0x0010
#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
/* FIXME: Code that sets/uses this is broken and needs to go away. */
#define PAGE_RESERVED 0x0020
#endif
#if defined(CONFIG_USER_ONLY)
void page_dump(FILE *f);
typedef int (*walk_memory_regions_fn)(void *, target_ulong,
target_ulong, unsigned long);
int walk_memory_regions(void *, walk_memory_regions_fn);
int page_get_flags(target_ulong address);
void page_set_flags(target_ulong start, target_ulong end, int flags);
int page_check_range(target_ulong start, target_ulong len, int flags);
#endif
CPUArchState *cpu_copy(CPUArchState *env);
/* Flags for use in ENV->INTERRUPT_PENDING.
The numbers assigned here are non-sequential in order to preserve
binary compatibility with the vmstate dump. Bit 0 (0x0001) was
previously used for CPU_INTERRUPT_EXIT, and is cleared when loading
the vmstate dump. */
/* External hardware interrupt pending. This is typically used for
interrupts from devices. */
#define CPU_INTERRUPT_HARD 0x0002
/* Exit the current TB. This is typically used when some system-level device
makes some change to the memory mapping. E.g. the a20 line change. */
#define CPU_INTERRUPT_EXITTB 0x0004
/* Halt the CPU. */
#define CPU_INTERRUPT_HALT 0x0020
/* Debug event pending. */
#define CPU_INTERRUPT_DEBUG 0x0080
/* Reset signal. */
#define CPU_INTERRUPT_RESET 0x0400
/* Several target-specific external hardware interrupts. Each target/cpu.h
should define proper names based on these defines. */
#define CPU_INTERRUPT_TGT_EXT_0 0x0008
#define CPU_INTERRUPT_TGT_EXT_1 0x0010
#define CPU_INTERRUPT_TGT_EXT_2 0x0040
#define CPU_INTERRUPT_TGT_EXT_3 0x0200
#define CPU_INTERRUPT_TGT_EXT_4 0x1000
/* Several target-specific internal interrupts. These differ from the
preceding target-specific interrupts in that they are intended to
originate from within the cpu itself, typically in response to some
instruction being executed. These, therefore, are not masked while
single-stepping within the debugger. */
#define CPU_INTERRUPT_TGT_INT_0 0x0100
#define CPU_INTERRUPT_TGT_INT_1 0x0800
#define CPU_INTERRUPT_TGT_INT_2 0x2000
/* First unused bit: 0x4000. */
/* The set of all bits that should be masked when single-stepping. */
#define CPU_INTERRUPT_SSTEP_MASK \
(CPU_INTERRUPT_HARD \
| CPU_INTERRUPT_TGT_EXT_0 \
| CPU_INTERRUPT_TGT_EXT_1 \
| CPU_INTERRUPT_TGT_EXT_2 \
| CPU_INTERRUPT_TGT_EXT_3 \
| CPU_INTERRUPT_TGT_EXT_4)
#if !defined(CONFIG_USER_ONLY)
/* memory API */
typedef struct RAMBlock RAMBlock;
struct RAMBlock {
struct rcu_head rcu;
struct MemoryRegion *mr;
uint8_t *host;
ram_addr_t offset;
ram_addr_t used_length;
ram_addr_t max_length;
void (*resized)(const char*, uint64_t length, void *host);
uint32_t flags;
/* Protected by iothread lock. */
char idstr[256];
/* RCU-enabled, writes protected by the ramlist lock */
QLIST_ENTRY(RAMBlock) next;
int fd;
};
static inline void *ramblock_ptr(RAMBlock *block, ram_addr_t offset)
{
assert(offset < block->used_length);
assert(block->host);
return (char *)block->host + offset;
}
typedef struct RAMList {
QemuMutex mutex;
/* Protected by the iothread lock. */
unsigned long *dirty_memory[DIRTY_MEMORY_NUM];
RAMBlock *mru_block;
/* RCU-enabled, writes protected by the ramlist lock. */
QLIST_HEAD(, RAMBlock) blocks;
uint32_t version;
} RAMList;
extern RAMList ram_list;
/* Flags stored in the low bits of the TLB virtual address. These are
defined so that fast path ram access is all zeros. */
/* Zero if TLB entry is valid. */
#define TLB_INVALID_MASK (1 << 3)
/* Set if TLB entry references a clean RAM page. The iotlb entry will
contain the page physical address. */
#define TLB_NOTDIRTY (1 << 4)
/* Set if TLB entry is an IO callback. */
#define TLB_MMIO (1 << 5)
void dump_exec_info(FILE *f, fprintf_function cpu_fprintf);
void dump_opcount_info(FILE *f, fprintf_function cpu_fprintf);
ram_addr_t last_ram_offset(void);
void qemu_mutex_lock_ramlist(void);
void qemu_mutex_unlock_ramlist(void);
#endif /* !CONFIG_USER_ONLY */
int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
uint8_t *buf, int len, int is_write);
#endif /* CPU_ALL_H */
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