Add the following functions to support caching of the
IRQ mapped entries:
kvmppc_cache_passthru_irq()
Caches an existing mapping in the cached array.
_uncache_passthru_irq()
Uncaches a cached entry. This is an internal function and
is only invoked when unmapping a passthrough IRQ mapping.
There is no support to just uncache an entry.
Signed-off-by: Suresh Warrier <warr...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/kvm_ppc.h | 1 +
arch/powerpc/kvm/book3s_hv.c | 97 ++++++++++++++++++++++++++++++++++++++
2 files changed, 98 insertions(+)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h
b/arch/powerpc/include/asm/kvm_ppc.h
index 75d4c64..4107f7f 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -291,6 +291,7 @@ struct kvmppc_ops {
struct irq_bypass_producer *);
void (*irq_bypass_del_producer)(struct irq_bypass_consumer *,
struct irq_bypass_producer *);
+ int (*cache_passthru_irq)(struct kvm *kvm, int irq);
};
extern struct kvmppc_ops *kvmppc_hv_ops;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 4d802b8..97150f0 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3297,6 +3297,95 @@ static struct kvmppc_passthru_irqmap
*kvmppc_alloc_pimap(struct irq_desc *desc)
return pimap;
}
+/*
+ * Cache a passthrough IRQ
+ * This is accomplished by copying the IRQ details from the
+ * mapped array to the cached array.
+ *
+ * Return:
+ * 0: if this was accomplished successfully
+ * 1: if the caching could not be done
+ */
+static int kvmppc_cache_passthru_irq_hv(struct kvm *kvm, int irq)
+{
+ struct kvmppc_passthru_irqmap *pimap;
+ int cidx, midx;
+
+ mutex_lock(&kvm->lock);
+
+ if (kvm->arch.pimap == NULL)
+ goto err_out;
+
+ pimap = kvm->arch.pimap;
+
+ /* Look for first empty slot */
+ for (cidx = 0; cidx < KVMPPC_PIRQ_CACHED; cidx++)
+ if (pimap->cached[cidx].r_hwirq == 0)
+ break;
+
+ /* Out of empty cache slots */
+ if (cidx == KVMPPC_PIRQ_CACHED)
+ goto err_out;
+
+ /* Find entry in the mapped array */
+ for (midx = 0; midx < pimap->n_mapped; midx++) {
+ if (irq == pimap->mapped[midx].v_hwirq)
+ break;
+ }
+
+ /* IRQ not found */
+ if (midx == pimap->n_mapped)
+ goto err_out;
+
+ if (pimap->mapped[midx].r_hwirq == 0)
+ /* Someone beat us to caching the IRQ */
+ goto err_out;
+
+ pimap->cached[cidx].v_hwirq = pimap->mapped[midx].v_hwirq;
+ pimap->cached[cidx].desc = pimap->mapped[midx].desc;
+ pimap->cached[cidx].r_hwirq = pimap->mapped[midx].r_hwirq;
+
+ if (cidx >= pimap->n_cached)
+ pimap->n_cached = cidx + 1;
+
+ /* r_hwirq == 0 in mapped array to indicate a cached IRQ */
+ pimap->mapped[midx].r_hwirq = 0;
+
+ mutex_unlock(&kvm->lock);
+ return 0;
+
+err_out:
+ mutex_unlock(&kvm->lock);
+ return 1;
+}
+
+/* Called with kvm->lock already acquired */
+static void _uncache_passthru_irq(struct kvmppc_passthru_irqmap *pimap, int
irq)
+{
+ int i;
+
+ for (i = 0; i < pimap->n_cached; i++) {
+ if (irq == pimap->cached[i].v_hwirq) {
+
+ /*
+ * Zero out the IRQ being uncached.
+ */
+ pimap->cached[i].r_hwirq = 0;
+ pimap->cached[i].v_hwirq = 0;
+ pimap->cached[i].desc = NULL;
+
+ /*
+ * Only need to decrement maximum cached count if
+ * this is the highest entry being uncached.
+ */
+ if (i + 1 == pimap->n_cached)
+ pimap->n_cached--;
+ return;
+ }
+ }
+
+}
+
static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int
guest_gsi)
{
struct irq_desc *desc;
@@ -3391,6 +3480,13 @@ static int kvmppc_clr_passthru_irq(struct kvm *kvm, int
host_irq, int guest_gsi)
}
/*
+ * If this is a cached IRQ, remove it from the cached array also
+ * mapped.r_hwirq is set to zero when we cache an entry.
+ */
+ if (!pimap->mapped[i].r_hwirq)
+ _uncache_passthru_irq(pimap, guest_gsi);
+
+ /*
* Replace mapped entry to be cleared with highest entry (unless
* this is already the highest) so as to not leave any holes in
* the array of mapped.
@@ -3567,6 +3663,7 @@ static struct kvmppc_ops kvm_ops_hv = {
#ifdef CONFIG_KVM_XICS
.irq_bypass_add_producer = kvmppc_irq_bypass_add_producer_hv,
.irq_bypass_del_producer = kvmppc_irq_bypass_del_producer_hv,
+ .cache_passthru_irq = kvmppc_cache_passthru_irq_hv,
#endif
};
--
1.8.3.4
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