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From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Jason Cooper <jason@lakedaemon.net>,
	Robert Richter <rrichter@marvell.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH v3 07/32] irqchip/gic-v4.1: Don't use the VPE proxy if RVPEID is set
Date: Tue, 24 Dec 2019 11:10:30 +0000
Message-ID: <20191224111055.11836-8-maz@kernel.org> (raw)
In-Reply-To: <20191224111055.11836-1-maz@kernel.org>

The infamous VPE proxy device isn't used with GICv4.1 because:
- we can invalidate any LPI from the DirectLPI MMIO interface
- the ITS and redistributors understand the life cycle of
  the doorbell, so we don't need to enable/disable it all
  the time

So let's escape early from the proxy related functions.

Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/irqchip/irq-gic-v3-its.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index e3c7d9ae0bdb..86c69b5cc156 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3213,7 +3213,7 @@ static const struct irq_domain_ops its_domain_ops = {
 /*
  * This is insane.
  *
- * If a GICv4 doesn't implement Direct LPIs (which is extremely
+ * If a GICv4.0 doesn't implement Direct LPIs (which is extremely
  * likely), the only way to perform an invalidate is to use a fake
  * device to issue an INV command, implying that the LPI has first
  * been mapped to some event on that device. Since this is not exactly
@@ -3221,9 +3221,20 @@ static const struct irq_domain_ops its_domain_ops = {
  * only issue an UNMAP if we're short on available slots.
  *
  * Broken by design(tm).
+ *
+ * GICv4.1, on the other hand, mandates that we're able to invalidate
+ * by writing to a MMIO register. It doesn't implement the whole of
+ * DirectLPI, but that's good enough. And most of the time, we don't
+ * even have to invalidate anything, as the redistributor can be told
+ * whether to generate a doorbell or not (we thus leave it enabled,
+ * always).
  */
 static void its_vpe_db_proxy_unmap_locked(struct its_vpe *vpe)
 {
+	/* GICv4.1 doesn't use a proxy, so nothing to do here */
+	if (gic_rdists->has_rvpeid)
+		return;
+
 	/* Already unmapped? */
 	if (vpe->vpe_proxy_event == -1)
 		return;
@@ -3246,6 +3257,10 @@ static void its_vpe_db_proxy_unmap_locked(struct its_vpe *vpe)
 
 static void its_vpe_db_proxy_unmap(struct its_vpe *vpe)
 {
+	/* GICv4.1 doesn't use a proxy, so nothing to do here */
+	if (gic_rdists->has_rvpeid)
+		return;
+
 	if (!gic_rdists->has_direct_lpi) {
 		unsigned long flags;
 
@@ -3257,6 +3272,10 @@ static void its_vpe_db_proxy_unmap(struct its_vpe *vpe)
 
 static void its_vpe_db_proxy_map_locked(struct its_vpe *vpe)
 {
+	/* GICv4.1 doesn't use a proxy, so nothing to do here */
+	if (gic_rdists->has_rvpeid)
+		return;
+
 	/* Already mapped? */
 	if (vpe->vpe_proxy_event != -1)
 		return;
@@ -3279,6 +3298,10 @@ static void its_vpe_db_proxy_move(struct its_vpe *vpe, int from, int to)
 	unsigned long flags;
 	struct its_collection *target_col;
 
+	/* GICv4.1 doesn't use a proxy, so nothing to do here */
+	if (gic_rdists->has_rvpeid)
+		return;
+
 	if (gic_rdists->has_direct_lpi) {
 		void __iomem *rdbase;
 
-- 
2.20.1

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  parent reply index

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-24 11:10 [PATCH v3 00/32] irqchip/gic-v4: GICv4.1 architecture support Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 01/32] irqchip/gic-v3: Detect GICv4.1 supporting RVPEID Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 02/32] irqchip/gic-v3: Add GICv4.1 VPEID size discovery Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 03/32] irqchip/gic-v3: Workaround Cavium TX1 erratum when reading GICD_TYPER2 Marc Zyngier
2020-03-09 22:11   ` Robert Richter
2020-03-10 11:41     ` Marc Zyngier
2020-03-10 12:34       ` Robert Richter
2020-03-11  8:45       ` Robert Richter
2020-03-11  9:03         ` Marc Zyngier
2020-03-11  9:18           ` Robert Richter
2019-12-24 11:10 ` [PATCH v3 04/32] irqchip/gic-v3: Use SGIs without active state if offered Marc Zyngier
2019-12-28  8:56   ` Zenghui Yu
2019-12-28 10:36     ` Marc Zyngier
2019-12-30  3:50       ` Zenghui Yu
2019-12-24 11:10 ` [PATCH v3 05/32] irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation Marc Zyngier
2020-01-20 14:03   ` Zenghui Yu
2020-01-20 15:11     ` Marc Zyngier
2020-01-22  2:59   ` Zenghui Yu
2019-12-24 11:10 ` [PATCH v3 06/32] irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP Marc Zyngier
2019-12-24 11:10 ` Marc Zyngier [this message]
2019-12-24 11:10 ` [PATCH v3 08/32] irqchip/gic-v4.1: Implement the v4.1 flavour of VMOVP Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 09/32] irqchip/gic-v4.1: Plumb skeletal VPE irqchip Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 10/32] irqchip/gic-v4.1: Add mask/unmask doorbell callbacks Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 11/32] irqchip/gic-v4.1: Add VPE residency callback Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 12/32] irqchip/gic-v4.1: Add VPE eviction callback Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 13/32] irqchip/gic-v4.1: Add VPE INVALL callback Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 14/32] irqchip/gic-v4.1: Suppress per-VLPI doorbell Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 15/32] irqchip/gic-v4.1: Allow direct invalidation of VLPIs Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 16/32] irqchip/gic-v4.1: Advertise support v4.1 to KVM Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 17/32] irqchip/gic-v4.1: Map the ITS SGIR register page Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 18/32] irqchip/gic-v4.1: Plumb skeletal VSGI irqchip Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 19/32] irqchip/gic-v4.1: Add initial SGI configuration Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 20/32] irqchip/gic-v4.1: Plumb mask/unmask SGI callbacks Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 21/32] irqchip/gic-v4.1: Plumb get/set_irqchip_state " Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 22/32] irqchip/gic-v4.1: Plumb set_vcpu_affinity " Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 23/32] irqchip/gic-v4.1: Move doorbell management to the GICv4 abstraction layer Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 24/32] irqchip/gic-v4.1: Add VSGI allocation/teardown Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 25/32] irqchip/gic-v4.1: Add VSGI property setup Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 26/32] irqchip/gic-v4.1: Eagerly vmap vPEs Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 27/32] KVM: arm64: GICv4.1: Let doorbells be auto-enabled Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 28/32] KVM: arm64: GICv4.1: Add direct injection capability to SGI registers Marc Zyngier
2019-12-28  9:19   ` Zenghui Yu
2019-12-28 10:41     ` Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 29/32] KVM: arm64: GICv4.1: Allow SGIs to switch between HW and SW interrupts Marc Zyngier
2020-01-15  2:49   ` Shaokun Zhang
2020-01-15  3:49     ` Zenghui Yu
2020-01-15 13:32       ` Marc Zyngier
2020-01-15 13:49         ` Zenghui Yu
2020-01-16  6:13         ` Shaokun Zhang
2020-01-15 13:17     ` Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 30/32] KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 31/32] KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disable Marc Zyngier
2019-12-24 11:10 ` [PATCH v3 32/32] KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs Marc Zyngier

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