On 16 May 2016 at 18:54, Sergey Fedorov <serge.f...@gmail.com> wrote: > On 16/05/16 19:09, Peter Maydell wrote: >> The exception_action() function in user-exec.c is just a call to >> cpu_loop_exit() for every target CPU except i386. Since this >> function is only called if the target's handle_mmu_fault() hook has >> indicated an MMU fault, and that hook is only called from the >> handle_cpu_signal() code path, we can simply move the x86-specific >> setup into that hook, which allows us to remove the TARGET_I386 >> ifdef from user-exec.c. >> >> Of the actions that were done by the call to raise_interrupt_err(): >> * cpu_svm_check_intercept_param() is a no-op in user mode >> * check_exception() is a no-op since double faults are impossible >> for user-mode >> * assignments to cs->exception_index and env->error_code are no-ops >> * cpu_loop_exit_restore() is equivalent to cpu_loop_exit() since >> pc is 0 >> which leaves just setting env_>exception_is_int and >> env->exception_next_eip as actions that need to be added to >> x86_cpu_handle_mmu_fault(). >> >> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> >> --- >> target-i386/helper.c | 2 ++ >> user-exec.c | 16 +--------------- >> 2 files changed, 3 insertions(+), 15 deletions(-) >> >> diff --git a/target-i386/helper.c b/target-i386/helper.c >> index bf3e762..e1dde46 100644 >> --- a/target-i386/helper.c >> +++ b/target-i386/helper.c >> @@ -700,6 +700,8 @@ int x86_cpu_handle_mmu_fault(CPUState *cs, vaddr addr, >> env->error_code = (is_write << PG_ERROR_W_BIT); >> env->error_code |= PG_ERROR_U_MASK; >> cs->exception_index = EXCP0E_PAGE; >> + env->exception_is_int = 0; >> + env->exception_next_eip = env->eip; > > 'env->eip' was updated by restore_state_to_opc() from > cpu_restore_state_from_tb() from cpu_restore_state() from > handle_cpu_signal() _after_ calling 'handle_mmu_fault' hook but _before_ > calling exception_action().
Oops, nice catch. (I wonder if any of the other target architectures are not correctly doing things in their handle_mmu_fault function because the cpu_restore_state() call happens later?) thanks -- PMM
