KVM: arm64: Delay the polling of the GICR_VPENDBASER.Dirty bit

In order to reduce the impact of the VPT parsing happening on the GIC,
we can split the vcpu reseidency in two phases:

- programming GICR_VPENDBASER: this still happens in vcpu_load()
- checking for the VPT parsing to be complete: this can happen
  on vcpu entry (in kvm_vgic_flush_hwstate())

This allows the GIC and the CPU to work in parallel, rewmoving some
of the entry overhead.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Shenming Lu <lushenming@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201128141857.983-3-lushenming@huawei.com

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-gic-v4.c b/drivers/irqchip/irq-gic-v4.c
index 0c18714ae13e..5d1dc9915272 100644
--- a/drivers/irqchip/irq-gic-v4.c
+++ b/drivers/irqchip/irq-gic-v4.c
@@ -232,6 +232,8 @@ int its_make_vpe_non_resident(struct its_vpe *vpe, bool db)
 	if (!ret)
 		vpe->resident = false;
 
+	vpe->ready = false;
+
 	return ret;
 }
 
@@ -258,6 +260,23 @@ int its_make_vpe_resident(struct its_vpe *vpe, bool g0en, bool g1en)
 	return ret;
 }
 
+int its_commit_vpe(struct its_vpe *vpe)
+{
+	struct its_cmd_info info = {
+		.cmd_type = COMMIT_VPE,
+	};
+	int ret;
+
+	WARN_ON(preemptible());
+
+	ret = its_send_vpe_cmd(vpe, &info);
+	if (!ret)
+		vpe->ready = true;
+
+	return ret;
+}
+
+
 int its_invall_vpe(struct its_vpe *vpe)
 {
 	struct its_cmd_info info = {