[PATCH 0/3] GICv3 ITS fixes for 6.8

[PATCH 0/3] GICv3 ITS fixes for 6.8

[Marc Zyngier]

Here's a small collection of patches that I posted separately in the
past, but that are all more or less related, so it makes sense to
repost them as a series.

It would be good to have them in 6.8, given that at least one of them
fixes a pretty bad regression, and the others can lead to
unpredictable behaviours.

Marc Zyngier (3):
  irqchip/gic-v3-its: Handle non-coherent GICv4 redistributors
  irqchip/gic-v3-its: Restore quirk probing for ACPI-based systems
  irqchip/gic-v3-its: Fix GICv4.1 VPE affinity update

 drivers/irqchip/irq-gic-v3-its.c | 62 ++++++++++++++++++++------------
 1 file changed, 40 insertions(+), 22 deletions(-)

-- 
2.39.2


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[PATCH 1/3] irqchip/gic-v3-its: Handle non-coherent GICv4 redistributors

[Marc Zyngier]

Although the GICv3 code base has gained some handling of systems
failing to handle the shareability attributes, the GICv4 side of
things has been firmly ignored.

This is unfortunate, as the new recent addition of the
"dma-noncoherent" is supposed to apply to all of the GICR tables,
and not just the ones that are common to v3 and v4.

Add some checks to handle the VPROPBASE/VPENDBASE shareability
and cacheability attributes in the same way we deal with the
other GICR_BASE registers, wrapping the flag check in a helper
for improved readability.

Note that this has been found by inspection only, as I don't
have access to HW that suffers from this particular issue.

Fixes: 3a0fff0fb6a3 ("irqchip/gic-v3: Enable non-coherent redistributors/ITSes DT probing")
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/irqchip/irq-gic-v3-its.c | 37 +++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index d097001c1e3e..fec1b58470df 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -207,6 +207,11 @@ 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 bool rdists_support_shareable(void)
+{
+	return !(gic_rdists->flags & RDIST_FLAGS_FORCE_NON_SHAREABLE);
+}
+
 static u16 get_its_list(struct its_vm *vm)
 {
 	struct its_node *its;
@@ -2710,10 +2715,12 @@ static u64 inherit_vpe_l1_table_from_its(void)
 			break;
 		}
 		val |= FIELD_PREP(GICR_VPROPBASER_4_1_ADDR, addr >> 12);
-		val |= FIELD_PREP(GICR_VPROPBASER_SHAREABILITY_MASK,
-				  FIELD_GET(GITS_BASER_SHAREABILITY_MASK, baser));
-		val |= FIELD_PREP(GICR_VPROPBASER_INNER_CACHEABILITY_MASK,
-				  FIELD_GET(GITS_BASER_INNER_CACHEABILITY_MASK, baser));
+		if (rdists_support_shareable()) {
+			val |= FIELD_PREP(GICR_VPROPBASER_SHAREABILITY_MASK,
+					  FIELD_GET(GITS_BASER_SHAREABILITY_MASK, baser));
+			val |= FIELD_PREP(GICR_VPROPBASER_INNER_CACHEABILITY_MASK,
+					  FIELD_GET(GITS_BASER_INNER_CACHEABILITY_MASK, baser));
+		}
 		val |= FIELD_PREP(GICR_VPROPBASER_4_1_SIZE, GITS_BASER_NR_PAGES(baser) - 1);
 
 		return val;
@@ -2936,8 +2943,10 @@ static int allocate_vpe_l1_table(void)
 	WARN_ON(!IS_ALIGNED(pa, psz));
 
 	val |= FIELD_PREP(GICR_VPROPBASER_4_1_ADDR, pa >> 12);
-	val |= GICR_VPROPBASER_RaWb;
-	val |= GICR_VPROPBASER_InnerShareable;
+	if (rdists_support_shareable()) {
+		val |= GICR_VPROPBASER_RaWb;
+		val |= GICR_VPROPBASER_InnerShareable;
+	}
 	val |= GICR_VPROPBASER_4_1_Z;
 	val |= GICR_VPROPBASER_4_1_VALID;
 
@@ -3126,7 +3135,7 @@ static void its_cpu_init_lpis(void)
 	gicr_write_propbaser(val, rbase + GICR_PROPBASER);
 	tmp = gicr_read_propbaser(rbase + GICR_PROPBASER);
 
-	if (gic_rdists->flags & RDIST_FLAGS_FORCE_NON_SHAREABLE)
+	if (!rdists_support_shareable())
 		tmp &= ~GICR_PROPBASER_SHAREABILITY_MASK;
 
 	if ((tmp ^ val) & GICR_PROPBASER_SHAREABILITY_MASK) {
@@ -3153,7 +3162,7 @@ static void its_cpu_init_lpis(void)
 	gicr_write_pendbaser(val, rbase + GICR_PENDBASER);
 	tmp = gicr_read_pendbaser(rbase + GICR_PENDBASER);
 
-	if (gic_rdists->flags & RDIST_FLAGS_FORCE_NON_SHAREABLE)
+	if (!rdists_support_shareable())
 		tmp &= ~GICR_PENDBASER_SHAREABILITY_MASK;
 
 	if (!(tmp & GICR_PENDBASER_SHAREABILITY_MASK)) {
@@ -3880,14 +3889,18 @@ static void its_vpe_schedule(struct its_vpe *vpe)
 	val  = virt_to_phys(page_address(vpe->its_vm->vprop_page)) &
 		GENMASK_ULL(51, 12);
 	val |= (LPI_NRBITS - 1) & GICR_VPROPBASER_IDBITS_MASK;
-	val |= GICR_VPROPBASER_RaWb;
-	val |= GICR_VPROPBASER_InnerShareable;
+	if (rdists_support_shareable()) {
+		val |= GICR_VPROPBASER_RaWb;
+		val |= GICR_VPROPBASER_InnerShareable;
+	}
 	gicr_write_vpropbaser(val, vlpi_base + GICR_VPROPBASER);
 
 	val  = virt_to_phys(page_address(vpe->vpt_page)) &
 		GENMASK_ULL(51, 16);
-	val |= GICR_VPENDBASER_RaWaWb;
-	val |= GICR_VPENDBASER_InnerShareable;
+	if (rdists_support_shareable()) {
+		val |= GICR_VPENDBASER_RaWaWb;
+		val |= GICR_VPENDBASER_InnerShareable;
+	}
 	/*
 	 * There is no good way of finding out if the pending table is
 	 * empty as we can race against the doorbell interrupt very
-- 
2.39.2


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[PATCH 2/3] irqchip/gic-v3-its: Restore quirk probing for ACPI-based systems

[Marc Zyngier]

While refactoring the way the ITSs are probed, the handling of
quirks applicable to ACPI-based platforms was lost. As a result,
systems such as HIP07 lose their GICv4 functionnality, and some
other may even fail to boot, unless they are configured to boot
with DT.

Move the enabling of quirks into its_probe_one(), making it
common to all firmware implementations.

Fixes: 9585a495ac93 ("irqchip/gic-v3-its: Split allocation from initialisation of its_node")
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
---
 drivers/irqchip/irq-gic-v3-its.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index fec1b58470df..250b4562f308 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -5091,6 +5091,8 @@ static int __init its_probe_one(struct its_node *its)
 	u32 ctlr;
 	int err;
 
+	its_enable_quirks(its);
+
 	if (is_v4(its)) {
 		if (!(its->typer & GITS_TYPER_VMOVP)) {
 			err = its_compute_its_list_map(its);
@@ -5442,7 +5444,6 @@ static int __init its_of_probe(struct device_node *node)
 		if (!its)
 			return -ENOMEM;
 
-		its_enable_quirks(its);
 		err = its_probe_one(its);
 		if (err)  {
 			its_node_destroy(its);
-- 
2.39.2


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[PATCH 3/3] irqchip/gic-v3-its: Fix GICv4.1 VPE affinity update

[Marc Zyngier]

When updating the affinity of a VPE, we currently skip the VMOVP
command if the two CPUs are part of the same VPE affinity.

But this is wrong, as the doorbell corresponding to this VPE
is still delivered on the 'old' CPU, which screws up the balancing.
Furthermore, offlining that 'old' CPU results in doorbell interrupts
generated for this VPE being discarded.

The harsh reality is that we cannot easily elide VMOVP when
a set_affinity request occurs. It needs to be obeyed, and if
an optimisation is to be made, it is at the point where the affinity
change request is made (such as in KVM).

Drop the VMOVP elision altogether, and only use the vpe_table_mask
to try and stay within the same ITS affinity group if at all possible.

Fixes: dd3f050a216e (irqchip/gic-v4.1: Implement the v4.1 flavour of VMOVP)
Reported-by: Kunkun Jiang <jiangkunkun@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
---
 drivers/irqchip/irq-gic-v3-its.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 250b4562f308..53abd4779914 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3826,8 +3826,9 @@ static int its_vpe_set_affinity(struct irq_data *d,
 				bool force)
 {
 	struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
-	int from, cpu = cpumask_first(mask_val);
+	struct cpumask common, *table_mask;
 	unsigned long flags;
+	int from, cpu;
 
 	/*
 	 * Changing affinity is mega expensive, so let's be as lazy as
@@ -3843,19 +3844,22 @@ static int its_vpe_set_affinity(struct irq_data *d,
 	 * taken on any vLPI handling path that evaluates vpe->col_idx.
 	 */
 	from = vpe_to_cpuid_lock(vpe, &flags);
-	if (from == cpu)
-		goto out;
-
-	vpe->col_idx = cpu;
+	table_mask = gic_data_rdist_cpu(from)->vpe_table_mask;
 
 	/*
-	 * GICv4.1 allows us to skip VMOVP if moving to a cpu whose RD
-	 * is sharing its VPE table with the current one.
+	 * If we are offered another CPU in the same GICv4.1 ITS
+	 * affinity, pick this one. Otherwise, any CPU will do.
 	 */
-	if (gic_data_rdist_cpu(cpu)->vpe_table_mask &&
-	    cpumask_test_cpu(from, gic_data_rdist_cpu(cpu)->vpe_table_mask))
+	if (table_mask && cpumask_and(&common, mask_val, table_mask))
+		cpu = cpumask_test_cpu(from, &common) ? from : cpumask_first(&common);
+	else
+		cpu = cpumask_first(mask_val);
+
+	if (from == cpu)
 		goto out;
 
+	vpe->col_idx = cpu;
+
 	its_send_vmovp(vpe);
 	its_vpe_db_proxy_move(vpe, from, cpu);
 
-- 
2.39.2


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