On Tue, Jan 12, 2016 at 4:42 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
>
>
> On 15/12/2015 19:32, David Matlack wrote:
> > What do you think about this simplification?
> >
> > bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
> > void *data)
> > jmp_buf jmpbuf;
> > int ret;
> >
> > handle_exception(ex, exception_handler);
> > ret = set_exception_jmpbuf(&jmpbuf);
> > if (ret == 0)
> > trigger_func(data);
> > handle_exception(ex, NULL);
> > return ret;
> > }
> >
> > Then trigger_func can be very simple, e.g.
> >
> > static void do_write_apicbase(u64 data)
> > {
> > wrmsr(MSR_IA32_APICBASE, data);
> > }
>
> I agree that's the best of both worlds.
>
> -------- 8< ------------
> From de1c13978b785e2aca82060ad3ccecdc04e75802 Mon Sep 17 00:00:00 2001
> From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Date: Tue, 12 Jan 2016 13:40:19 +0100
> Subject: [PATCH kvm-unit-tests] x86: simplify test_for_exception trigger
> functions
>
> test_for_exception makes the unit tests simpler, but it requires the
> trigger function to be in on the joke: before, by calling
> set_exception_return; now, by calling set_exception_jmpbuf and
> handle_exception(NULL). The new setjmp-based implementation
> lets us move all of this into test_for_exception itself, so
> that the trigger_func can be very simple.
Looks good. Thanks!
>
> Suggested-by: David Matlack <dmatlack@xxxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> lib/x86/desc.c | 10 +++++++---
> x86/apic.c | 5 +----
> x86/vmx.c | 12 +++---------
> 3 files changed, 11 insertions(+), 16 deletions(-)
>
> diff --git a/lib/x86/desc.c b/lib/x86/desc.c
> index acf29e3..17aedcf 100644
> --- a/lib/x86/desc.c
> +++ b/lib/x86/desc.c
> @@ -333,11 +333,15 @@ static void exception_handler(struct ex_regs *regs)
> bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
> void *data)
> {
> + jmp_buf jmpbuf;
> + int ret;
> +
> handle_exception(ex, exception_handler);
> - exception = false;
> - trigger_func(data);
> + ret = set_exception_jmpbuf(&jmpbuf);
> + if (ret == 0)
> + trigger_func(data);
> handle_exception(ex, NULL);
> - return exception;
> + return ret;
> }
>
> void __set_exception_jmpbuf(jmp_buf *addr)
> diff --git a/x86/apic.c b/x86/apic.c
> index 2e04c82..61a0a76 100644
> --- a/x86/apic.c
> +++ b/x86/apic.c
> @@ -63,10 +63,7 @@ static void test_tsc_deadline_timer(void)
>
> static void do_write_apicbase(void *data)
> {
> - jmp_buf jmpbuf;
> - if (set_exception_jmpbuf(jmpbuf) == 0) {
> - wrmsr(MSR_IA32_APICBASE, *(u64 *)data);
> - }
> + wrmsr(MSR_IA32_APICBASE, *(u64 *)data);
> }
>
> void test_enable_x2apic(void)
> diff --git a/x86/vmx.c b/x86/vmx.c
> index 12ec396..3fa1a73 100644
> --- a/x86/vmx.c
> +++ b/x86/vmx.c
> @@ -617,19 +617,13 @@ static void init_vmx(void)
>
> static void do_vmxon_off(void *data)
> {
> - jmp_buf jmpbuf;
> - if (set_exception_jmpbuf(jmpbuf) == 0) {
> - vmx_on();
> - vmx_off();
> - }
> + vmx_on();
> + vmx_off();
> }
>
> static void do_write_feature_control(void *data)
> {
> - jmp_buf jmpbuf;
> - if (set_exception_jmpbuf(jmpbuf) == 0) {
> - wrmsr(MSR_IA32_FEATURE_CONTROL, 0);
> - }
> + wrmsr(MSR_IA32_FEATURE_CONTROL, 0);
> }
>
> static int test_vmx_feature_control(void)
> --
> 2.5.0
>
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