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intc/arm_gic: Implement virtualization extensions in gic_(deactivate|complete_irq)

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Implement virtualization extensions in the gic_deactivate_irq() and
gic_complete_irq() functions.

When the guest writes an invalid vIRQ to V_EOIR or V_DIR, since the
GICv2 specification is not entirely clear here, we adopt the behaviour
observed on real hardware:
  * When V_CTRL.EOIMode is false (EOI split is disabled):
    - In case of an invalid vIRQ write to V_EOIR:
      -> If some bits are set in H_APR, an invalid vIRQ write to V_EOIR
         triggers a priority drop, and increments V_HCR.EOICount.
      -> If V_APR is already cleared, nothing happen

    - An invalid vIRQ write to V_DIR is ignored.

  * When V_CTRL.EOIMode is true:
    - In case of an invalid vIRQ write to V_EOIR:
      -> If some bits are set in H_APR, an invalid vIRQ write to V_EOIR
         triggers a priority drop.
      -> If V_APR is already cleared, nothing happen

    - An invalid vIRQ write to V_DIR increments V_HCR.EOICount.

Signed-off-by: Luc Michel <luc.michel@greensocs.com>
Message-id: 20180727095421.386-13-luc.michel@greensocs.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Luc Michel 2018-08-14 17:17:20 +01:00 committed by Peter Maydell
parent 439badd66d
commit 02f2e22d7c
1 changed files with 47 additions and 4 deletions
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51
hw/intc/arm_gic.c
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@ -583,20 +583,19 @@ static void gic_deactivate_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs)
{
int group;
if (irq >= s->num_irq) {
if (irq >= GIC_MAXIRQ || (!gic_is_vcpu(cpu) && irq >= s->num_irq)) {
/*
* This handles two cases:
* 1. If software writes the ID of a spurious interrupt [ie 1023]
* to the GICC_DIR, the GIC ignores that write.
* 2. If software writes the number of a non-existent interrupt
* this must be a subcase of "value written is not an active interrupt"
* and so this is UNPREDICTABLE. We choose to ignore it.
* and so this is UNPREDICTABLE. We choose to ignore it. For vCPUs,
* all IRQs potentially exist, so this limit does not apply.
*/
return;
}
group = gic_has_groups(s) && gic_test_group(s, irq, cpu);
if (!gic_eoi_split(s, cpu, attrs)) {
/* This is UNPREDICTABLE; we choose to ignore it */
qemu_log_mask(LOG_GUEST_ERROR,
@ -604,6 +603,17 @@ static void gic_deactivate_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs)
return;
}
if (gic_is_vcpu(cpu) && !gic_virq_is_valid(s, irq, cpu)) {
/* This vIRQ does not have an LR entry which is either active or
* pending and active. Increment EOICount and ignore the write.
*/
int rcpu = gic_get_vcpu_real_id(cpu);
s->h_hcr[rcpu] += 1 << R_GICH_HCR_EOICount_SHIFT;
return;
}
group = gic_has_groups(s) && gic_test_group(s, irq, cpu);
if (gic_cpu_ns_access(s, cpu, attrs) && !group) {
DPRINTF("Non-secure DI for Group0 interrupt %d ignored\n", irq);
return;
@ -618,6 +628,39 @@ static void gic_complete_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs)
int group;
DPRINTF("EOI %d\n", irq);
if (gic_is_vcpu(cpu)) {
/* The call to gic_prio_drop() will clear a bit in GICH_APR iff the
* running prio is < 0x100.
*/
bool prio_drop = s->running_priority[cpu] < 0x100;
if (irq >= GIC_MAXIRQ) {
/* Ignore spurious interrupt */
return;
}
gic_drop_prio(s, cpu, 0);
if (!gic_eoi_split(s, cpu, attrs)) {
bool valid = gic_virq_is_valid(s, irq, cpu);
if (prio_drop && !valid) {
/* We are in a situation where:
* - V_CTRL.EOIMode is false (no EOI split),
* - The call to gic_drop_prio() cleared a bit in GICH_APR,
* - This vIRQ does not have an LR entry which is either
* active or pending and active.
* In that case, we must increment EOICount.
*/
int rcpu = gic_get_vcpu_real_id(cpu);
s->h_hcr[rcpu] += 1 << R_GICH_HCR_EOICount_SHIFT;
} else if (valid) {
gic_clear_active(s, irq, cpu);
}
}
return;
}
if (irq >= s->num_irq) {
/* This handles two cases:
* 1. If software writes the ID of a spurious interrupt [ie 1023]