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

Paolo Bonzini
2013-09-15T09:54:07Z

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).

> 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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