[PATCH kvm-unit-tests] x86: ioapic: add tests around retriggering of level interrupts

[PATCH kvm-unit-tests] x86: ioapic: add tests around retriggering of level interrupts

[Paolo Bonzini]

Test resampling of level interrupts after EOI, by leaving the IRQ
line set in the ISR.  One tests does reset the IRQ line after a while,
the other uses masking instead in the ISR.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 x86/ioapic.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/x86/ioapic.c b/x86/ioapic.c
index 1fcf67e..d43d5c1 100644
--- a/x86/ioapic.c
+++ b/x86/ioapic.c
@@ -188,6 +188,31 @@ static void test_ioapic_level_sequential(void)
 	report("sequential level interrupts", g_isr_99 == 2);
 }
 
+static volatile int g_isr_9a;
+
+static void ioapic_isr_9a(isr_regs_t *regs)
+{
+	++g_isr_9a;
+	if (g_isr_9a == 2)
+		set_irq_line(0x0e, 0);
+	eoi();
+}
+
+static void test_ioapic_level_retrigger(void)
+{
+	handle_irq(0x9a, ioapic_isr_9a);
+	set_ioapic_redir(0x0e, 0x9a, LEVEL_TRIGGERED);
+
+	asm volatile ("cli");
+	set_irq_line(0x0e, 1);
+	while (g_isr_9a != 2)
+		asm volatile ("sti; hlt; cli");
+
+	asm volatile ("sti");
+
+	report("retriggered level interrupts without masking", g_isr_9a == 2);
+}
+
 static volatile int g_isr_81;
 
 static void ioapic_isr_81(isr_regs_t *regs)
@@ -242,6 +267,30 @@ static void test_ioapic_level_mask(void)
 	report("unmasked level interrupt", g_isr_82 == 1);
 }
 
+static volatile int g_isr_83;
+
+static void ioapic_isr_83(isr_regs_t *regs)
+{
+	++g_isr_83;
+	set_mask(0x0e, true);
+	eoi();
+}
+
+static void test_ioapic_level_retrigger_mask(void)
+{
+	handle_irq(0x83, ioapic_isr_83);
+	set_ioapic_redir(0x0e, 0x83, LEVEL_TRIGGERED);
+
+	set_irq_line(0x0e, 1);
+	asm volatile ("nop");
+	set_mask(0x0e, false);
+	asm volatile ("nop");
+	report("retriggered level interrupts with mask", g_isr_83 == 2);
+
+	set_irq_line(0x0e, 0);
+	set_mask(0x0e, false);
+}
+
 
 int main(void)
 {
@@ -263,9 +312,11 @@ int main(void)
 	test_ioapic_simultaneous();
 	test_ioapic_level_coalesce();
 	test_ioapic_level_sequential();
+	test_ioapic_level_retrigger();
 
 	test_ioapic_edge_mask();
 	test_ioapic_level_mask();
+	test_ioapic_level_retrigger_mask();
 
 	return report_summary();
 }
-- 
1.8.3.1

Re: [PATCH kvm-unit-tests] x86: ioapic: add tests around retriggering of level interrupts

[Steve Rutherford]

On Wed, Jul 29, 2015 at 03:28:13PM +0200, Paolo Bonzini wrote:
> Test resampling of level interrupts after EOI, by leaving the IRQ
> line set in the ISR.  One tests does reset the IRQ line after a while,
> the other uses masking instead in the ISR.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  x86/ioapic.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/x86/ioapic.c b/x86/ioapic.c
> index 1fcf67e..d43d5c1 100644
> --- a/x86/ioapic.c
> +++ b/x86/ioapic.c
> @@ -188,6 +188,31 @@ static void test_ioapic_level_sequential(void)
>  	report("sequential level interrupts", g_isr_99 == 2);
>  }
>  
> +static volatile int g_isr_9a;
> +
> +static void ioapic_isr_9a(isr_regs_t *regs)
> +{
> +	++g_isr_9a;
> +	if (g_isr_9a == 2)
> +		set_irq_line(0x0e, 0);
> +	eoi();
> +}
> +
> +static void test_ioapic_level_retrigger(void)
> +{
> +	handle_irq(0x9a, ioapic_isr_9a);
> +	set_ioapic_redir(0x0e, 0x9a, LEVEL_TRIGGERED);
> +
> +	asm volatile ("cli");
> +	set_irq_line(0x0e, 1);
> +	while (g_isr_9a != 2)
> +		asm volatile ("sti; hlt; cli");
This seems sketchy. The test should be able to exit this and fail.

Steve

Re: [PATCH kvm-unit-tests] x86: ioapic: add tests around retriggering of level interrupts

[Paolo Bonzini]

On 30/07/2015 05:14, Steve Rutherford wrote:
>> > +static void test_ioapic_level_retrigger(void)
>> > +{
>> > +	handle_irq(0x9a, ioapic_isr_9a);
>> > +	set_ioapic_redir(0x0e, 0x9a, LEVEL_TRIGGERED);
>> > +
>> > +	asm volatile ("cli");
>> > +	set_irq_line(0x0e, 1);
>> > +	while (g_isr_9a != 2)
>> > +		asm volatile ("sti; hlt; cli");
> This seems sketchy. The test should be able to exit this and fail.

You're right, this shouldn't take more than 10-15 iterations of the
while loop.

Paolo