On 2020-03-17 02:49, Zenghui Yu wrote:
Hi Marc,
On 2020/3/5 4:33, Marc Zyngier wrote:
Now that we have HW-accelerated SGIs being delivered to VPEs, it
becomes required to map the VPEs on all ITSs instead of relying
on the lazy approach that we would use when using the ITS-list
mechanism.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Before GICv4.1, we use vlpi_count to evaluate whether the vPE has been
mapped on the specified ITS, and use this refcount to only issue VMOVP
to those involved ITSes. It's broken after this patch.
We may need to re-evaluate "whether the vPE is mapped" now that we're
at
GICv4.1, otherwise *no* VMOVP will be issued on the v4.1 capable
machine
(I mean those without single VMOVP support).
What I'm saying is something like below (only an idea, it even can't
compile), any thoughts?
diff --git a/drivers/irqchip/irq-gic-v3-its.c
b/drivers/irqchip/irq-gic-v3-its.c
index 2e12bc52e3a2..3450b5e847ca 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -198,7 +198,8 @@ static u16 get_its_list(struct its_vm *vm)
if (!is_v4(its))
continue;
- if (vm->vlpi_count[its->list_nr])
+ if (vm->vlpi_count[its->list_nr] ||
+ gic_requires_eager_mapping())
__set_bit(its->list_nr, &its_list);
}
@@ -1295,7 +1296,8 @@ static void its_send_vmovp(struct its_vpe *vpe)
if (!is_v4(its))
continue;
- if (!vpe->its_vm->vlpi_count[its->list_nr])
+ if (!vpe->its_vm->vlpi_count[its->list_nr] &&
+ !gic_requires_eager_mapping())
continue;
desc.its_vmovp_cmd.col = &its->collections[col_id];
It took me a while to wrap my head around that one, but you're as usual
spot on.
The use of gic_requires_eager_mapping() is a bit confusing here, as it
isn't
so much that the VPE is eagerly mapped, but the predicate on which we
evaluate
the need for a VMOVP. How about this:
diff --git a/drivers/irqchip/irq-gic-v3-its.c
b/drivers/irqchip/irq-gic-v3-its.c
index cd6451e190c9..348f7a909a69 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -189,6 +189,15 @@ static DEFINE_IDA(its_vpeid_ida);
#define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
#define gic_data_rdist_vlpi_base() (gic_data_rdist_rd_base() + SZ_128K)
+/*
+ * Skip ITSs that have no vLPIs mapped, unless we're on GICv4.1, as we
+ * always have vSGIs mapped.
+ */
+static bool require_its_list_vmovp(struct its_vm *vm, struct its_node
*its)
+{
+ return (gic_rdists->has_rvpeid || vm->vlpi_count[its->list_nr]);
+}
+
static u16 get_its_list(struct its_vm *vm)
{
struct its_node *its;
@@ -198,7 +207,7 @@ static u16 get_its_list(struct its_vm *vm)
if (!is_v4(its))
continue;
- if (vm->vlpi_count[its->list_nr])
+ if (require_its_list_vmovp(vm, its))
__set_bit(its->list_nr, &its_list);
}
@@ -1295,7 +1304,7 @@ static void its_send_vmovp(struct its_vpe *vpe)
if (!is_v4(its))
continue;
- if (!vpe->its_vm->vlpi_count[its->list_nr])
+ if (!require_its_list_vmovp(vpe->its_vm, its))
continue;
desc.its_vmovp_cmd.col = &its->collections[col_id];
Thanks,
M.
--
Jazz is not dead. It just smells funny...
