Re: [PATCH kvm-unit-tests] Test fault during IRET from NMI.

Gleb Natapov
2013-09-15T09:56:51Z

On Sun, Sep 15, 2013 at 11:54:15AM +0200, Paolo Bonzini wrote:
> Il 15/09/2013 10:17, Gleb Natapov ha scritto:
> > This test checks that NMI window opens only after IRET from NMI is
> > executed without a fault.
> >
> > Signed-off-by: Gleb Natapov <gleb@redhat.com>
>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>
> ... with a couple English nits (see inline).
>
Yeah, those are copy/paste from other places. The file is full of it :)

> > diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> > index e46d8d0..de1dc47 100644
> > --- a/lib/x86/processor.h
> > +++ b/lib/x86/processor.h
> > @@ -62,6 +62,13 @@ static inline u16 read_gs(void)
> > return val;
> > }
> >
> > +static inline unsigned long read_rflags(void)
> > +{
> > + unsigned long f;
> > + asm ("pushf; pop %0\n\t" : "=rm"(f));
> > + return f;
> > +}
> > +
> > static inline void write_ds(unsigned val)
> > {
> > asm ("mov %0, %%ds" : : "rm"(val) : "memory");
> > diff --git a/x86/eventinj.c b/x86/eventinj.c
> > index 7bed7c5..c171e30 100644
> > --- a/x86/eventinj.c
> > +++ b/x86/eventinj.c
> > @@ -125,6 +125,42 @@ static void nmi_isr(struct ex_regs *r)
> > printf("After nested NMI to itself\n");
> > }
> >
> > +unsigned long after_iret_addr;
> > +
> > +static void nested_nmi_iret_isr(struct ex_regs *r)
> > +{
> > + printf("Nested NMI isr running rip=%x\n", r->rip);
> > +
> > + if (r->rip == after_iret_addr)
> > + test_count++;
> > +}
> > +static void nmi_iret_isr(struct ex_regs *r)
> > +{
> > + unsigned long *s = alloc_page();
> > + test_count++;
> > + printf("NMI isr running %p stack %p\n", &&after_iret, s);
> > + handle_exception(2, nested_nmi_iret_isr);
> > + printf("Try send nested NMI to itself\n");
>
> s/Try send/Sending/
>
> > + apic_self_nmi();
> > + printf("After nested NMI to itself\n");
> > + s[4] = read_ss();
> > + s[3] = 0; /* rsp */
> > + s[2] = read_rflags();
> > + s[1] = read_cs();
> > + s[0] = after_iret_addr = (unsigned long)&&after_iret;
> > + asm ("mov %%rsp, %0\n\t"
> > + "mov %1, %%rsp\n\t"
> > + "outl %2, $0xe4\n\t" /* flush stack page */
> > +#ifdef __x86_64__
> > + "iretq\n\t"
> > +#else
> > + "iretl\n\t"
> > +#endif
> > + : "=m"(s[3]) : "rm"(&s[0]), "a"((unsigned int)virt_to_phys(s)) : "memory");
> > +after_iret:
> > + printf("After iret\n");
> > +}
> > +
> > static void tirq0(isr_regs_t *r)
> > {
> > printf("irq0 running\n");
> > @@ -300,6 +336,20 @@ int main()
> > irq_disable();
> > report("NMI", test_count == 2);
> >
> > + /* generate NMI that will fault on IRET */
> > + printf("Before NMI IRET test\n");
> > + test_count = 0;
> > + handle_exception(2, nmi_iret_isr);
> > + printf("Try send NMI to itself\n");
>
> s/Try send/Sending/
>
> > + apic_self_nmi();
> > + /* this is needed on VMX without NMI window notificatoin.
>
> s/notifiatoin/notification/
>
> > + Interrupt windows is used instead, so let pending NMI
> > + to be injected */
> > + irq_enable();
> > + asm volatile ("nop");
> > + irq_disable();
> > + printf("After NMI to itself\n");
> > + report("NMI", test_count == 2);
> > #ifndef __x86_64__
> > stack_phys = (ulong)virt_to_phys(alloc_page());
> > stack_va = alloc_vpage();
> > --
> > Gleb.
> > --
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> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >

--
Gleb.