diff options
authorPeter Maydell <peter.maydell@linaro.org>2017-07-31 17:41:21 +0100
committerPeter Maydell <peter.maydell@linaro.org>2017-08-02 17:59:00 +0100
commit1599b61a8c33e332783eccf730d86fea6ab0f559 (patch)
parentae1c604c6cc74631c5cd5cfae8255f6a825ef065 (diff)
cpu: Define new cpu_transaction_failed() hook
Currently we have a rather half-baked setup for allowing CPUs to generate exceptions on accesses to invalid memory: the CPU has a cpu_unassigned_access() hook which the memory system calls in unassigned_mem_write() and unassigned_mem_read() if the current_cpu pointer is non-NULL. This was originally designed before we implemented the MemTxResult type that allows memory operations to report a success or failure code, which is why the hook is called right at the bottom of the memory system. The major problem with this is that it means that the hook can be called even when the access was not actually done by the CPU: for instance if the CPU writes to a DMA engine register which causes the DMA engine to begin a transaction which has been set up by the guest to operate on invalid memory then this will casue the CPU to take an exception incorrectly. Another minor problem is that currently if a device returns a transaction error then this won't turn into a CPU exception at all. The right way to do this is to have allow the CPU to respond to memory system transaction failures at the point where the CPU specific code calls into the memory system. Define a new QOM CPU method and utility function cpu_transaction_failed() which is called in these cases. The functionality here overlaps with the existing cpu_unassigned_access() because individual target CPUs will need some work to convert them to the new system. When this transition is complete we can remove the old cpu_unassigned_access() code. Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
1 files changed, 21 insertions, 0 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 25eefea7ab..fc54d5584b 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -85,8 +85,10 @@ struct TranslationBlock;
* @has_work: Callback for checking if there is work to do.
* @do_interrupt: Callback for interrupt handling.
* @do_unassigned_access: Callback for unassigned access handling.
+ * (this is deprecated: new targets should use do_transaction_failed instead)
* @do_unaligned_access: Callback for unaligned access handling, if
* the target defines #ALIGNED_ONLY.
+ * @do_transaction_failed: Callback for handling failed memory transactions
* @virtio_is_big_endian: Callback to return %true if a CPU which supports
* runtime configurable endianness is currently big-endian. Non-configurable
* CPUs can use the default implementation of this method. This method should
@@ -153,6 +155,10 @@ typedef struct CPUClass {
void (*do_unaligned_access)(CPUState *cpu, vaddr addr,
MMUAccessType access_type,
int mmu_idx, uintptr_t retaddr);
+ void (*do_transaction_failed)(CPUState *cpu, hwaddr physaddr, vaddr addr,
+ unsigned size, MMUAccessType access_type,
+ int mmu_idx, MemTxAttrs attrs,
+ MemTxResult response, uintptr_t retaddr);
bool (*virtio_is_big_endian)(CPUState *cpu);
int (*memory_rw_debug)(CPUState *cpu, vaddr addr,
uint8_t *buf, int len, bool is_write);
@@ -837,6 +843,21 @@ static inline void cpu_unaligned_access(CPUState *cpu, vaddr addr,
cc->do_unaligned_access(cpu, addr, access_type, mmu_idx, retaddr);
+static inline void cpu_transaction_failed(CPUState *cpu, hwaddr physaddr,
+ vaddr addr, unsigned size,
+ MMUAccessType access_type,
+ int mmu_idx, MemTxAttrs attrs,
+ MemTxResult response,
+ uintptr_t retaddr)
+ CPUClass *cc = CPU_GET_CLASS(cpu);
+ if (cc->do_transaction_failed) {
+ cc->do_transaction_failed(cpu, physaddr, addr, size, access_type,
+ mmu_idx, attrs, response, retaddr);
+ }
#endif /* NEED_CPU_H */