On Thu, Sep 2, 2021 at 9:17 AM Philippe Mathieu-Daudé <f4...@amsat.org>
wrote:
> do_interrupt() is sysemu specific. However due to some X86
> specific hack, it is also used in user-mode emulation, which
> is why it couldn't be restricted to CONFIG_SOFTMMU (see the
> comment around added in commit 78271684719: "cpu: tcg_ops:
> move to tcg-cpu-ops.h, keep a pointer in CPUClass").
> Keep the hack but rename the handler as fake_user_exception()
> and restrict do_interrupt() to sysemu.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> ---
> RFC: Any better name / idea here?
>
Maybe user_mode_exception()? but I'm not sure that's better...
> ---
> include/hw/core/tcg-cpu-ops.h | 22 ++++++++++++++--------
> accel/tcg/cpu-exec.c | 4 ++--
> target/i386/tcg/tcg-cpu.c | 6 ++++--
> 3 files changed, 20 insertions(+), 12 deletions(-)
>
Reviewed-by: Warner Losh <i...@bsdimp.com>
> diff --git a/include/hw/core/tcg-cpu-ops.h b/include/hw/core/tcg-cpu-ops.h
> index eab27d0c030..600f0349659 100644
> --- a/include/hw/core/tcg-cpu-ops.h
> +++ b/include/hw/core/tcg-cpu-ops.h
> @@ -37,14 +37,6 @@ struct TCGCPUOps {
> void (*cpu_exec_exit)(CPUState *cpu);
> /** @cpu_exec_interrupt: Callback for processing interrupts in
> cpu_exec */
> bool (*cpu_exec_interrupt)(CPUState *cpu, int interrupt_request);
> - /**
> - * @do_interrupt: Callback for interrupt handling.
> - *
> - * note that this is in general SOFTMMU only, but it actually isn't
> - * because of an x86 hack (accel/tcg/cpu-exec.c), so we cannot put it
> - * in the SOFTMMU section in general.
> - */
> - void (*do_interrupt)(CPUState *cpu);
> /**
> * @tlb_fill: Handle a softmmu tlb miss or user-only address fault
> *
> @@ -61,6 +53,20 @@ struct TCGCPUOps {
> void (*debug_excp_handler)(CPUState *cpu);
>
> #ifdef NEED_CPU_H
> +#if defined(CONFIG_USER_ONLY) && defined(TARGET_I386)
> + /**
> + * @fake_user_exception: Callback for 'fake exception' handling.
> + *
> + * Simulate 'fake exception' which will be handled outside the
> + * cpu execution loop (hack for x86 user mode).
> + */
> + void (*fake_user_exception)(CPUState *cpu);
> +#else
> + /**
> + * @do_interrupt: Callback for interrupt handling.
> + */
> + void (*do_interrupt)(CPUState *cpu);
> +#endif /* !CONFIG_USER_ONLY || !TARGET_I386 */
> #ifdef CONFIG_SOFTMMU
> /**
> * @do_transaction_failed: Callback for handling failed memory
> transactions
> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index e5c0ccd1a2a..3e387c944c5 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -651,8 +651,8 @@ static inline bool cpu_handle_exception(CPUState *cpu,
> int *ret)
> loop */
> #if defined(TARGET_I386)
> CPUClass *cc = CPU_GET_CLASS(cpu);
> - cc->tcg_ops->do_interrupt(cpu);
> -#endif
> + cc->tcg_ops->fake_user_exception(cpu);
> +#endif /* TARGET_I386 */
> *ret = cpu->exception_index;
> cpu->exception_index = -1;
> return true;
> diff --git a/target/i386/tcg/tcg-cpu.c b/target/i386/tcg/tcg-cpu.c
> index 93a79a57415..dce800a8953 100644
> --- a/target/i386/tcg/tcg-cpu.c
> +++ b/target/i386/tcg/tcg-cpu.c
> @@ -73,9 +73,11 @@ static const struct TCGCPUOps x86_tcg_ops = {
> .cpu_exec_enter = x86_cpu_exec_enter,
> .cpu_exec_exit = x86_cpu_exec_exit,
> .cpu_exec_interrupt = x86_cpu_exec_interrupt,
> - .do_interrupt = x86_cpu_do_interrupt,
> .tlb_fill = x86_cpu_tlb_fill,
> -#ifndef CONFIG_USER_ONLY
> +#ifdef CONFIG_USER_ONLY
> + .fake_user_exception = x86_cpu_do_interrupt,
> +#else
> + .do_interrupt = x86_cpu_do_interrupt,
> .debug_excp_handler = breakpoint_handler,
> .debug_check_breakpoint = x86_debug_check_breakpoint,
> #endif /* !CONFIG_USER_ONLY */
> --
> 2.31.1
>
>
