From 04e3aabde397e7abc78ba1ce6cbd144d5fbb1722 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 4 Sep 2017 15:21:55 +0100 Subject: cputlb: Support generating CPU exceptions on memory transaction failures Call the new cpu_transaction_failed() hook at the places where CPU generated code interacts with the memory system: io_readx() io_writex() get_page_addr_code() Any access from C code (eg via cpu_physical_memory_rw(), address_space_rw(), ld/st_*_phys()) will *not* trigger CPU exceptions via cpu_transaction_failed(). Handling for transactions failures for this kind of call should be done by using a function which returns a MemTxResult and treating the failure case appropriately in the calling code. In an ideal world we would not generate CPU exceptions for instruction fetch failures in get_page_addr_code() but instead wait until the code translation process tried a load and it failed; however that change would require too great a restructuring and redesign to attempt at this point. Signed-off-by: Peter Maydell Reviewed-by: Edgar E. Iglesias --- accel/tcg/cputlb.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) (limited to 'accel') diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index 85635ae8ad..e72415a882 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -747,6 +747,7 @@ static inline ram_addr_t qemu_ram_addr_from_host_nofail(void *ptr) } static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry, + int mmu_idx, target_ulong addr, uintptr_t retaddr, int size) { CPUState *cpu = ENV_GET_CPU(env); @@ -754,6 +755,7 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry, MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs); uint64_t val; bool locked = false; + MemTxResult r; physaddr = (physaddr & TARGET_PAGE_MASK) + addr; cpu->mem_io_pc = retaddr; @@ -767,7 +769,12 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry, qemu_mutex_lock_iothread(); locked = true; } - memory_region_dispatch_read(mr, physaddr, &val, size, iotlbentry->attrs); + r = memory_region_dispatch_read(mr, physaddr, + &val, size, iotlbentry->attrs); + if (r != MEMTX_OK) { + cpu_transaction_failed(cpu, physaddr, addr, size, MMU_DATA_LOAD, + mmu_idx, iotlbentry->attrs, r, retaddr); + } if (locked) { qemu_mutex_unlock_iothread(); } @@ -776,6 +783,7 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry, } static void io_writex(CPUArchState *env, CPUIOTLBEntry *iotlbentry, + int mmu_idx, uint64_t val, target_ulong addr, uintptr_t retaddr, int size) { @@ -783,6 +791,7 @@ static void io_writex(CPUArchState *env, CPUIOTLBEntry *iotlbentry, hwaddr physaddr = iotlbentry->addr; MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs); bool locked = false; + MemTxResult r; physaddr = (physaddr & TARGET_PAGE_MASK) + addr; if (mr != &io_mem_rom && mr != &io_mem_notdirty && !cpu->can_do_io) { @@ -795,7 +804,12 @@ static void io_writex(CPUArchState *env, CPUIOTLBEntry *iotlbentry, qemu_mutex_lock_iothread(); locked = true; } - memory_region_dispatch_write(mr, physaddr, val, size, iotlbentry->attrs); + r = memory_region_dispatch_write(mr, physaddr, + val, size, iotlbentry->attrs); + if (r != MEMTX_OK) { + cpu_transaction_failed(cpu, physaddr, addr, size, MMU_DATA_STORE, + mmu_idx, iotlbentry->attrs, r, retaddr); + } if (locked) { qemu_mutex_unlock_iothread(); } @@ -845,6 +859,7 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env, target_ulong addr) MemoryRegion *mr; CPUState *cpu = ENV_GET_CPU(env); CPUIOTLBEntry *iotlbentry; + hwaddr physaddr; index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1); mmu_idx = cpu_mmu_index(env, true); @@ -868,6 +883,19 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env, target_ulong addr) } qemu_mutex_unlock_iothread(); + /* Give the new-style cpu_transaction_failed() hook first chance + * to handle this. + * This is not the ideal place to detect and generate CPU + * exceptions for instruction fetch failure (for instance + * we don't know the length of the access that the CPU would + * use, and it would be better to go ahead and try the access + * and use the MemTXResult it produced). However it is the + * simplest place we have currently available for the check. + */ + physaddr = (iotlbentry->addr & TARGET_PAGE_MASK) + addr; + cpu_transaction_failed(cpu, physaddr, addr, 0, MMU_INST_FETCH, mmu_idx, + iotlbentry->attrs, MEMTX_DECODE_ERROR, 0); + cpu_unassigned_access(cpu, addr, false, true, 0, 4); /* The CPU's unassigned access hook might have longjumped out * with an exception. If it didn't (or there was no hook) then -- cgit v1.2.1