[PATCH v2 0/9] KVM: arm64: Initial host support for the Apple M1

[PATCH v2 0/9] KVM: arm64: Initial host support for the Apple M1

[Marc Zyngier]

This is a new version of the series initially posted at [1], reworking
the vGIC and timer code to cope with the M1 braindead^Wamusing nature.

Not much has changed, except for the missing irq_ack callback when
taking a timer interrupt, which would leave a screaming interrupt.

Tested with multiple concurrent VMs running from an initramfs.

* From v1 [1]:
  - Rebased on Hector's v4 posting[0]
  - Dropped a couple of patches that have been merged in the above series
  - Fixed irq_ack callback on the timer path

[0] https://lore.kernel.org/r/20210402090542.131194-1-marcan@marcan.st
[1] https://lore.kernel.org/r/20210316174617.173033-1-maz@kernel.org

Marc Zyngier (9):
  irqchip/gic: Split vGIC probing information from the GIC code
  KVM: arm64: Handle physical FIQ as an IRQ while running a guest
  KVM: arm64: vgic: Be tolerant to the lack of maintenance interrupt
  KVM: arm64: vgic: Let an interrupt controller advertise lack of HW
    deactivation
  KVM: arm64: vgic: move irq->get_input_level into an ops structure
  KVM: arm64: vgic: Implement SW-driven deactivation
  KVM: arm64: timer: Refactor IRQ configuration
  KVM: arm64: timer: Add support for SW-based deactivation
  irqchip/apple-aic: Advertise some level of vGICv3 compatibility

 arch/arm64/kvm/arch_timer.c            | 161 +++++++++++++++++++++----
 arch/arm64/kvm/hyp/hyp-entry.S         |   6 +-
 arch/arm64/kvm/vgic/vgic-init.c        |  33 ++++-
 arch/arm64/kvm/vgic/vgic-v2.c          |  19 ++-
 arch/arm64/kvm/vgic/vgic-v3.c          |  19 ++-
 arch/arm64/kvm/vgic/vgic.c             |  14 +--
 drivers/irqchip/irq-apple-aic.c        |   8 ++
 drivers/irqchip/irq-gic-common.c       |  13 --
 drivers/irqchip/irq-gic-common.h       |   2 -
 drivers/irqchip/irq-gic-v3.c           |   6 +-
 drivers/irqchip/irq-gic.c              |   6 +-
 include/kvm/arm_vgic.h                 |  41 +++++--
 include/linux/irqchip/arm-gic-common.h |  25 +---
 include/linux/irqchip/arm-vgic-info.h  |  43 +++++++
 14 files changed, 290 insertions(+), 106 deletions(-)
 create mode 100644 include/linux/irqchip/arm-vgic-info.h

-- 
2.29.2

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[PATCH v2 1/9] irqchip/gic: Split vGIC probing information from the GIC code

[Marc Zyngier]

The vGIC advertising code is unsurprisingly very much tied to
the GIC implementations. However, we are about to extend the
support to lesser implementations.

Let's dissociate the vgic registration from the GIC code and
move it into KVM, where it makes a bit more sense. This also
allows us to mark the gic_kvm_info structures as __initdata.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-init.c        | 17 +++++++++--
 drivers/irqchip/irq-gic-common.c       | 13 --------
 drivers/irqchip/irq-gic-common.h       |  2 --
 drivers/irqchip/irq-gic-v3.c           |  6 ++--
 drivers/irqchip/irq-gic.c              |  6 ++--
 include/linux/irqchip/arm-gic-common.h | 25 +---------------
 include/linux/irqchip/arm-vgic-info.h  | 41 ++++++++++++++++++++++++++
 7 files changed, 62 insertions(+), 48 deletions(-)
 create mode 100644 include/linux/irqchip/arm-vgic-info.h

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 052917deb149..9b491263f5f7 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -480,6 +480,15 @@ static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static struct gic_kvm_info *gic_kvm_info;
+
+void __init vgic_set_kvm_info(const struct gic_kvm_info *info)
+{
+	BUG_ON(gic_kvm_info != NULL);
+	gic_kvm_info = kmalloc(sizeof(*info), GFP_KERNEL);
+	*gic_kvm_info = *info;
+}
+
 /**
  * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
  *
@@ -507,10 +516,8 @@ void kvm_vgic_init_cpu_hardware(void)
  */
 int kvm_vgic_hyp_init(void)
 {
-	const struct gic_kvm_info *gic_kvm_info;
 	int ret;
 
-	gic_kvm_info = gic_get_kvm_info();
 	if (!gic_kvm_info)
 		return -ENODEV;
 
@@ -534,10 +541,14 @@ int kvm_vgic_hyp_init(void)
 		ret = -ENODEV;
 	}
 
+	kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
+
+	kfree(gic_kvm_info);
+	gic_kvm_info = NULL;
+
 	if (ret)
 		return ret;
 
-	kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 	ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 				 vgic_maintenance_handler,
 				 "vgic", kvm_get_running_vcpus());
diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c
index f47b41dfd023..a610821c8ff2 100644
--- a/drivers/irqchip/irq-gic-common.c
+++ b/drivers/irqchip/irq-gic-common.c
@@ -12,19 +12,6 @@
 
 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
 
-static const struct gic_kvm_info *gic_kvm_info;
-
-const struct gic_kvm_info *gic_get_kvm_info(void)
-{
-	return gic_kvm_info;
-}
-
-void gic_set_kvm_info(const struct gic_kvm_info *info)
-{
-	BUG_ON(gic_kvm_info != NULL);
-	gic_kvm_info = info;
-}
-
 void gic_enable_of_quirks(const struct device_node *np,
 			  const struct gic_quirk *quirks, void *data)
 {
diff --git a/drivers/irqchip/irq-gic-common.h b/drivers/irqchip/irq-gic-common.h
index ccba8b0fe0f5..27e3d4ed4f32 100644
--- a/drivers/irqchip/irq-gic-common.h
+++ b/drivers/irqchip/irq-gic-common.h
@@ -28,6 +28,4 @@ void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 void gic_enable_of_quirks(const struct device_node *np,
 			  const struct gic_quirk *quirks, void *data);
 
-void gic_set_kvm_info(const struct gic_kvm_info *info);
-
 #endif /* _IRQ_GIC_COMMON_H */
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index eb0ee356a629..3bd0f25a342f 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -103,7 +103,7 @@ EXPORT_SYMBOL(gic_nonsecure_priorities);
 /* ppi_nmi_refs[n] == number of cpus having ppi[n + 16] set as NMI */
 static refcount_t *ppi_nmi_refs;
 
-static struct gic_kvm_info gic_v3_kvm_info;
+static struct gic_kvm_info gic_v3_kvm_info __initdata;
 static DEFINE_PER_CPU(bool, has_rss);
 
 #define MPIDR_RS(mpidr)			(((mpidr) & 0xF0UL) >> 4)
@@ -1852,7 +1852,7 @@ static void __init gic_of_setup_kvm_info(struct device_node *node)
 
 	gic_v3_kvm_info.has_v4 = gic_data.rdists.has_vlpis;
 	gic_v3_kvm_info.has_v4_1 = gic_data.rdists.has_rvpeid;
-	gic_set_kvm_info(&gic_v3_kvm_info);
+	vgic_set_kvm_info(&gic_v3_kvm_info);
 }
 
 static int __init gic_of_init(struct device_node *node, struct device_node *parent)
@@ -2168,7 +2168,7 @@ static void __init gic_acpi_setup_kvm_info(void)
 
 	gic_v3_kvm_info.has_v4 = gic_data.rdists.has_vlpis;
 	gic_v3_kvm_info.has_v4_1 = gic_data.rdists.has_rvpeid;
-	gic_set_kvm_info(&gic_v3_kvm_info);
+	vgic_set_kvm_info(&gic_v3_kvm_info);
 }
 
 static int __init
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index b1d9c22caf2e..2de9ec8ece0c 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -119,7 +119,7 @@ static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key);
 
 static struct gic_chip_data gic_data[CONFIG_ARM_GIC_MAX_NR] __read_mostly;
 
-static struct gic_kvm_info gic_v2_kvm_info;
+static struct gic_kvm_info gic_v2_kvm_info __initdata;
 
 static DEFINE_PER_CPU(u32, sgi_intid);
 
@@ -1451,7 +1451,7 @@ static void __init gic_of_setup_kvm_info(struct device_node *node)
 		return;
 
 	if (static_branch_likely(&supports_deactivate_key))
-		gic_set_kvm_info(&gic_v2_kvm_info);
+		vgic_set_kvm_info(&gic_v2_kvm_info);
 }
 
 int __init
@@ -1618,7 +1618,7 @@ static void __init gic_acpi_setup_kvm_info(void)
 
 	gic_v2_kvm_info.maint_irq = irq;
 
-	gic_set_kvm_info(&gic_v2_kvm_info);
+	vgic_set_kvm_info(&gic_v2_kvm_info);
 }
 
 static int __init gic_v2_acpi_init(union acpi_subtable_headers *header,
diff --git a/include/linux/irqchip/arm-gic-common.h b/include/linux/irqchip/arm-gic-common.h
index fa8c0455c352..1177f3a1aed5 100644
--- a/include/linux/irqchip/arm-gic-common.h
+++ b/include/linux/irqchip/arm-gic-common.h
@@ -7,8 +7,7 @@
 #ifndef __LINUX_IRQCHIP_ARM_GIC_COMMON_H
 #define __LINUX_IRQCHIP_ARM_GIC_COMMON_H
 
-#include <linux/types.h>
-#include <linux/ioport.h>
+#include <linux/irqchip/arm-vgic-info.h>
 
 #define GICD_INT_DEF_PRI		0xa0
 #define GICD_INT_DEF_PRI_X4		((GICD_INT_DEF_PRI << 24) |\
@@ -16,28 +15,6 @@
 					(GICD_INT_DEF_PRI << 8) |\
 					GICD_INT_DEF_PRI)
 
-enum gic_type {
-	GIC_V2,
-	GIC_V3,
-};
-
-struct gic_kvm_info {
-	/* GIC type */
-	enum gic_type	type;
-	/* Virtual CPU interface */
-	struct resource vcpu;
-	/* Interrupt number */
-	unsigned int	maint_irq;
-	/* Virtual control interface */
-	struct resource vctrl;
-	/* vlpi support */
-	bool		has_v4;
-	/* rvpeid support */
-	bool		has_v4_1;
-};
-
-const struct gic_kvm_info *gic_get_kvm_info(void);
-
 struct irq_domain;
 struct fwnode_handle;
 int gicv2m_init(struct fwnode_handle *parent_handle,
diff --git a/include/linux/irqchip/arm-vgic-info.h b/include/linux/irqchip/arm-vgic-info.h
new file mode 100644
index 000000000000..0319636be928
--- /dev/null
+++ b/include/linux/irqchip/arm-vgic-info.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * include/linux/irqchip/arm-vgic-info.h
+ *
+ * Copyright (C) 2016 ARM Limited, All Rights Reserved.
+ */
+#ifndef __ARM_VGIC_INFO_H
+#define __ARM_VGIC_INFO_H
+
+#include <linux/types.h>
+#include <linux/ioport.h>
+
+enum gic_type {
+	/* Full GICv2 */
+	GIC_V2,
+	/* Full GICv3, optionally with v2 compat */
+	GIC_V3,
+};
+
+struct gic_kvm_info {
+	/* GIC type */
+	enum gic_type	type;
+	/* Virtual CPU interface */
+	struct resource vcpu;
+	/* Interrupt number */
+	unsigned int	maint_irq;
+	/* Virtual control interface */
+	struct resource vctrl;
+	/* vlpi support */
+	bool		has_v4;
+	/* rvpeid support */
+	bool		has_v4_1;
+};
+
+#ifdef CONFIG_KVM
+void vgic_set_kvm_info(const struct gic_kvm_info *info);
+#else
+static inline void vgic_set_kvm_info(const struct gic_kvm_info *info) {}
+#endif
+
+#endif
-- 
2.29.2

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[PATCH v2 2/9] KVM: arm64: Handle physical FIQ as an IRQ while running a guest

[Marc Zyngier]

As we we now entertain the possibility of FIQ being used on the host,
treat the signalling of a FIQ while running a guest as an IRQ,
causing an exit instead of a HYP panic.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/hyp-entry.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 5f49df4ffdd8..9aa9b73475c9 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -76,6 +76,7 @@ el1_trap:
 	b	__guest_exit
 
 el1_irq:
+el1_fiq:
 	get_vcpu_ptr	x1, x0
 	mov	x0, #ARM_EXCEPTION_IRQ
 	b	__guest_exit
@@ -131,7 +132,6 @@ SYM_CODE_END(\label)
 	invalid_vector	el2t_error_invalid
 	invalid_vector	el2h_irq_invalid
 	invalid_vector	el2h_fiq_invalid
-	invalid_vector	el1_fiq_invalid
 
 	.ltorg
 
@@ -179,12 +179,12 @@ SYM_CODE_START(__kvm_hyp_vector)
 
 	valid_vect	el1_sync		// Synchronous 64-bit EL1
 	valid_vect	el1_irq			// IRQ 64-bit EL1
-	invalid_vect	el1_fiq_invalid		// FIQ 64-bit EL1
+	valid_vect	el1_fiq			// FIQ 64-bit EL1
 	valid_vect	el1_error		// Error 64-bit EL1
 
 	valid_vect	el1_sync		// Synchronous 32-bit EL1
 	valid_vect	el1_irq			// IRQ 32-bit EL1
-	invalid_vect	el1_fiq_invalid		// FIQ 32-bit EL1
+	valid_vect	el1_fiq			// FIQ 32-bit EL1
 	valid_vect	el1_error		// Error 32-bit EL1
 SYM_CODE_END(__kvm_hyp_vector)
 
-- 
2.29.2

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[PATCH v2 3/9] KVM: arm64: vgic: Be tolerant to the lack of maintenance interrupt

[Marc Zyngier]

As it turns out, not all the interrupt controllers are able to
expose a vGIC maintenance interrupt as a distrete signal.
And to be fair, it doesn't really matter as all we require is
for *something* to kick us out of guest mode out way or another.

On systems that do not expose a maintenance interrupt as such,
there are two outcomes:

- either the virtual CPUIF does generate an interrupt, and
  by the time we are back to the host the interrupt will have long
  been disabled (as we set ICH_HCR_EL2.EN to 0 on exit). In this case,
  interrupt latency is as good as it gets.

- or some other event (physical timer) will take us out of the guest
  anyway, and the only drawback is a bad interrupt latency.

So let's be tolerant to the lack of maintenance interrupt, and just let
the user know that their mileage may vary...

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-init.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 9b491263f5f7..00c75495fd0c 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -521,11 +521,6 @@ int kvm_vgic_hyp_init(void)
 	if (!gic_kvm_info)
 		return -ENODEV;
 
-	if (!gic_kvm_info->maint_irq) {
-		kvm_err("No vgic maintenance irq\n");
-		return -ENXIO;
-	}
-
 	switch (gic_kvm_info->type) {
 	case GIC_V2:
 		ret = vgic_v2_probe(gic_kvm_info);
@@ -549,6 +544,11 @@ int kvm_vgic_hyp_init(void)
 	if (ret)
 		return ret;
 
+	if (!kvm_vgic_global_state.maint_irq) {
+		kvm_err("No maintenance interrupt available, fingers crossed...\n");
+		return 0;
+	}
+
 	ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 				 vgic_maintenance_handler,
 				 "vgic", kvm_get_running_vcpus());
-- 
2.29.2

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[PATCH v2 4/9] KVM: arm64: vgic: Let an interrupt controller advertise lack of HW deactivation

[Marc Zyngier]

The vGIC, as architected by ARM, allows a virtual interrupt to
trigger the deactivation of a physical interrupt. This allows
the following interrupt to be delivered without requiring an exit.

However, some implementations have choosen not to implement this,
meaning that we will need some unsavoury workarounds to deal with this.

On detecting such a case, taint the kernel and spit a nastygram.
We'll deal with this in later patches.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-init.c       | 10 ++++++++++
 include/kvm/arm_vgic.h                |  3 +++
 include/linux/irqchip/arm-vgic-info.h |  2 ++
 3 files changed, 15 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 00c75495fd0c..0c8637a58535 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -521,6 +521,16 @@ int kvm_vgic_hyp_init(void)
 	if (!gic_kvm_info)
 		return -ENODEV;
 
+	/*
+	 * If we get one of these oddball non-GICs, taint the kernel,
+	 * as we have no idea of how they *really* behave.
+	 */
+	if (gic_kvm_info->no_hw_deactivation) {
+		kvm_info("Non-architectural vgic, tainting kernel\n");
+		add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+		kvm_vgic_global_state.no_hw_deactivation = true;
+	}
+
 	switch (gic_kvm_info->type) {
 	case GIC_V2:
 		ret = vgic_v2_probe(gic_kvm_info);
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 3d74f1060bd1..7afe789194d8 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -72,6 +72,9 @@ struct vgic_global {
 	bool			has_gicv4;
 	bool			has_gicv4_1;
 
+	/* Pseudo GICv3 from outer space */
+	bool			no_hw_deactivation;
+
 	/* GIC system register CPU interface */
 	struct static_key_false gicv3_cpuif;
 
diff --git a/include/linux/irqchip/arm-vgic-info.h b/include/linux/irqchip/arm-vgic-info.h
index 0319636be928..d39d0b591c5a 100644
--- a/include/linux/irqchip/arm-vgic-info.h
+++ b/include/linux/irqchip/arm-vgic-info.h
@@ -30,6 +30,8 @@ struct gic_kvm_info {
 	bool		has_v4;
 	/* rvpeid support */
 	bool		has_v4_1;
+	/* Deactivation impared, subpar stuff */
+	bool		no_hw_deactivation;
 };
 
 #ifdef CONFIG_KVM
-- 
2.29.2

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[PATCH v2 5/9] KVM: arm64: vgic: move irq->get_input_level into an ops structure

[Marc Zyngier]

We already have the option to attach a callback to an interrupt
to retrieve its pending state. As we are planning to expand this
facility, move this callback into its own data structure.

This will limit the size of individual interrupts as the ops
structures can be shared across multiple interrupts.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arch_timer.c |  8 ++++++--
 arch/arm64/kvm/vgic/vgic.c  | 14 +++++++-------
 include/kvm/arm_vgic.h      | 28 +++++++++++++++++-----------
 3 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 74e0699661e9..e2288b6bf435 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1116,6 +1116,10 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	return kvm_timer_should_fire(timer);
 }
 
+static struct irq_ops arch_timer_irq_ops = {
+	.get_input_level = kvm_arch_timer_get_input_level,
+};
+
 int kvm_timer_enable(struct kvm_vcpu *vcpu)
 {
 	struct arch_timer_cpu *timer = vcpu_timer(vcpu);
@@ -1143,7 +1147,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 	ret = kvm_vgic_map_phys_irq(vcpu,
 				    map.direct_vtimer->host_timer_irq,
 				    map.direct_vtimer->irq.irq,
-				    kvm_arch_timer_get_input_level);
+				    &arch_timer_irq_ops);
 	if (ret)
 		return ret;
 
@@ -1151,7 +1155,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 		ret = kvm_vgic_map_phys_irq(vcpu,
 					    map.direct_ptimer->host_timer_irq,
 					    map.direct_ptimer->irq.irq,
-					    kvm_arch_timer_get_input_level);
+					    &arch_timer_irq_ops);
 	}
 
 	if (ret)
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 1c597c9885fa..1d22365c68e2 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -182,8 +182,8 @@ bool vgic_get_phys_line_level(struct vgic_irq *irq)
 
 	BUG_ON(!irq->hw);
 
-	if (irq->get_input_level)
-		return irq->get_input_level(irq->intid);
+	if (irq->ops && irq->ops->get_input_level)
+		return irq->ops->get_input_level(irq->intid);
 
 	WARN_ON(irq_get_irqchip_state(irq->host_irq,
 				      IRQCHIP_STATE_PENDING,
@@ -479,7 +479,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 /* @irq->irq_lock must be held */
 static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 			    unsigned int host_irq,
-			    bool (*get_input_level)(int vindid))
+			    struct irq_ops *ops)
 {
 	struct irq_desc *desc;
 	struct irq_data *data;
@@ -499,7 +499,7 @@ static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 	irq->hw = true;
 	irq->host_irq = host_irq;
 	irq->hwintid = data->hwirq;
-	irq->get_input_level = get_input_level;
+	irq->ops = ops;
 	return 0;
 }
 
@@ -508,11 +508,11 @@ static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
 {
 	irq->hw = false;
 	irq->hwintid = 0;
-	irq->get_input_level = NULL;
+	irq->ops = NULL;
 }
 
 int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
-			  u32 vintid, bool (*get_input_level)(int vindid))
+			  u32 vintid, struct irq_ops *ops)
 {
 	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 	unsigned long flags;
@@ -521,7 +521,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
 	BUG_ON(!irq);
 
 	raw_spin_lock_irqsave(&irq->irq_lock, flags);
-	ret = kvm_vgic_map_irq(vcpu, irq, host_irq, get_input_level);
+	ret = kvm_vgic_map_irq(vcpu, irq, host_irq, ops);
 	raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 	vgic_put_irq(vcpu->kvm, irq);
 
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 7afe789194d8..a7130f1b5ab9 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -92,6 +92,21 @@ enum vgic_irq_config {
 	VGIC_CONFIG_LEVEL
 };
 
+/*
+ * Per-irq ops overriding some common behavious.
+ *
+ * Always called in non-preemptible section and the functions can use
+ * kvm_arm_get_running_vcpu() to get the vcpu pointer for private IRQs.
+ */
+struct irq_ops {
+	/*
+	 * Callback function pointer to in-kernel devices that can tell us the
+	 * state of the input level of mapped level-triggered IRQ faster than
+	 * peaking into the physical GIC.
+	 */
+	bool (*get_input_level)(int vintid);
+};
+
 struct vgic_irq {
 	raw_spinlock_t irq_lock;	/* Protects the content of the struct */
 	struct list_head lpi_list;	/* Used to link all LPIs together */
@@ -129,16 +144,7 @@ struct vgic_irq {
 	u8 group;			/* 0 == group 0, 1 == group 1 */
 	enum vgic_irq_config config;	/* Level or edge */
 
-	/*
-	 * Callback function pointer to in-kernel devices that can tell us the
-	 * state of the input level of mapped level-triggered IRQ faster than
-	 * peaking into the physical GIC.
-	 *
-	 * Always called in non-preemptible section and the functions can use
-	 * kvm_arm_get_running_vcpu() to get the vcpu pointer for private
-	 * IRQs.
-	 */
-	bool (*get_input_level)(int vintid);
+	struct irq_ops *ops;
 
 	void *owner;			/* Opaque pointer to reserve an interrupt
 					   for in-kernel devices. */
@@ -354,7 +360,7 @@ void kvm_vgic_init_cpu_hardware(void);
 int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 			bool level, void *owner);
 int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
-			  u32 vintid, bool (*get_input_level)(int vindid));
+			  u32 vintid, struct irq_ops *ops);
 int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid);
 bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid);
 
-- 
2.29.2

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[PATCH v2 6/9] KVM: arm64: vgic: Implement SW-driven deactivation

[Marc Zyngier]

In order to deal with these systems that do not offer HW-based
deactivation of interrupts, let implement a SW-based approach:

- When the irq is queued into a LR, treat it as a pure virtual
  interrupt and set the EOI flag in the LR.

- When the interrupt state is read back from the LR, force a
  deactivation when the state is invalid (neither active nor
  pending)

Interrupts requiring such treatment get the VGIC_SW_RESAMPLE flag.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-v2.c | 19 +++++++++++++++----
 arch/arm64/kvm/vgic/vgic-v3.c | 19 +++++++++++++++----
 include/kvm/arm_vgic.h        | 10 ++++++++++
 3 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-v2.c b/arch/arm64/kvm/vgic/vgic-v2.c
index 11934c2af2f4..2c580204f1dc 100644
--- a/arch/arm64/kvm/vgic/vgic-v2.c
+++ b/arch/arm64/kvm/vgic/vgic-v2.c
@@ -108,11 +108,22 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
 		 * If this causes us to lower the level, we have to also clear
 		 * the physical active state, since we will otherwise never be
 		 * told when the interrupt becomes asserted again.
+		 *
+		 * Another case is when the interrupt requires a helping hand
+		 * on deactivation (no HW deactivation, for example).
 		 */
-		if (vgic_irq_is_mapped_level(irq) && (val & GICH_LR_PENDING_BIT)) {
-			irq->line_level = vgic_get_phys_line_level(irq);
+		if (vgic_irq_is_mapped_level(irq)) {
+			bool resample = false;
+
+			if (val & GICH_LR_PENDING_BIT) {
+				irq->line_level = vgic_get_phys_line_level(irq);
+				resample = !irq->line_level;
+			} else if (vgic_irq_needs_resampling(irq) &&
+				   !(irq->active || irq->pending_latch)) {
+				resample = true;
+			}
 
-			if (!irq->line_level)
+			if (resample)
 				vgic_irq_set_phys_active(irq, false);
 		}
 
@@ -152,7 +163,7 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
 	if (irq->group)
 		val |= GICH_LR_GROUP1;
 
-	if (irq->hw) {
+	if (irq->hw && !vgic_irq_needs_resampling(irq)) {
 		val |= GICH_LR_HW;
 		val |= irq->hwintid << GICH_LR_PHYSID_CPUID_SHIFT;
 		/*
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 6f530925a231..d7ee88de3a5c 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -99,11 +99,22 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
 		 * If this causes us to lower the level, we have to also clear
 		 * the physical active state, since we will otherwise never be
 		 * told when the interrupt becomes asserted again.
+		 *
+		 * Another case is when the interrupt requires a helping hand
+		 * on deactivation (no HW deactivation, for example).
 		 */
-		if (vgic_irq_is_mapped_level(irq) && (val & ICH_LR_PENDING_BIT)) {
-			irq->line_level = vgic_get_phys_line_level(irq);
+		if (vgic_irq_is_mapped_level(irq)) {
+			bool resample = false;
+
+			if (val & ICH_LR_PENDING_BIT) {
+				irq->line_level = vgic_get_phys_line_level(irq);
+				resample = !irq->line_level;
+			} else if (vgic_irq_needs_resampling(irq) &&
+				   !(irq->active || irq->pending_latch)) {
+				resample = true;
+			}
 
-			if (!irq->line_level)
+			if (resample)
 				vgic_irq_set_phys_active(irq, false);
 		}
 
@@ -134,7 +145,7 @@ void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
 		}
 	}
 
-	if (irq->hw) {
+	if (irq->hw && !vgic_irq_needs_resampling(irq)) {
 		val |= ICH_LR_HW;
 		val |= ((u64)irq->hwintid) << ICH_LR_PHYS_ID_SHIFT;
 		/*
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index a7130f1b5ab9..379ee0c97ede 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -99,6 +99,11 @@ enum vgic_irq_config {
  * kvm_arm_get_running_vcpu() to get the vcpu pointer for private IRQs.
  */
 struct irq_ops {
+	/* Per interrupt flags for special-cased interrupts */
+	unsigned long flags;
+
+#define VGIC_IRQ_SW_RESAMPLE	BIT(0)	/* Clear the active state for resampling */
+
 	/*
 	 * Callback function pointer to in-kernel devices that can tell us the
 	 * state of the input level of mapped level-triggered IRQ faster than
@@ -150,6 +155,11 @@ struct vgic_irq {
 					   for in-kernel devices. */
 };
 
+static inline bool vgic_irq_needs_resampling(struct vgic_irq *irq)
+{
+	return irq->ops && (irq->ops->flags & VGIC_IRQ_SW_RESAMPLE);
+}
+
 struct vgic_register_region;
 struct vgic_its;
 
-- 
2.29.2

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[PATCH v2 7/9] KVM: arm64: timer: Refactor IRQ configuration

[Marc Zyngier]

As we are about to add some more things to the timer IRQ
configuration, move this code out of the main timer init code
into its own set of functions.

No functional changes.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arch_timer.c | 61 ++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index e2288b6bf435..7fa4f446456a 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -973,6 +973,39 @@ static int kvm_timer_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
+static void kvm_irq_fixup_flags(unsigned int virq, u32 *flags)
+{
+	*flags = irq_get_trigger_type(virq);
+	if (*flags != IRQF_TRIGGER_HIGH && *flags != IRQF_TRIGGER_LOW) {
+		kvm_err("Invalid trigger for timer IRQ%d, assuming level low\n",
+			virq);
+		*flags = IRQF_TRIGGER_LOW;
+	}
+}
+
+static int kvm_irq_init(struct arch_timer_kvm_info *info)
+{
+	struct irq_domain *domain = NULL;
+	struct fwnode_handle *fwnode;
+	struct irq_data *data;
+
+	if (info->virtual_irq <= 0) {
+		kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n",
+			info->virtual_irq);
+		return -ENODEV;
+	}
+
+	host_vtimer_irq = info->virtual_irq;
+	kvm_irq_fixup_flags(host_vtimer_irq, &host_vtimer_irq_flags);
+
+	if (info->physical_irq > 0) {
+		host_ptimer_irq = info->physical_irq;
+		kvm_irq_fixup_flags(host_ptimer_irq, &host_ptimer_irq_flags);
+	}
+
+	return 0;
+}
+
 int kvm_timer_hyp_init(bool has_gic)
 {
 	struct arch_timer_kvm_info *info;
@@ -986,22 +1019,11 @@ int kvm_timer_hyp_init(bool has_gic)
 		return -ENODEV;
 	}
 
-	/* First, do the virtual EL1 timer irq */
-
-	if (info->virtual_irq <= 0) {
-		kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n",
-			info->virtual_irq);
-		return -ENODEV;
-	}
-	host_vtimer_irq = info->virtual_irq;
+	err = kvm_irq_init(info);
+	if (err)
+		return err;
 
-	host_vtimer_irq_flags = irq_get_trigger_type(host_vtimer_irq);
-	if (host_vtimer_irq_flags != IRQF_TRIGGER_HIGH &&
-	    host_vtimer_irq_flags != IRQF_TRIGGER_LOW) {
-		kvm_err("Invalid trigger for vtimer IRQ%d, assuming level low\n",
-			host_vtimer_irq);
-		host_vtimer_irq_flags = IRQF_TRIGGER_LOW;
-	}
+	/* First, do the virtual EL1 timer irq */
 
 	err = request_percpu_irq(host_vtimer_irq, kvm_arch_timer_handler,
 				 "kvm guest vtimer", kvm_get_running_vcpus());
@@ -1027,15 +1049,6 @@ int kvm_timer_hyp_init(bool has_gic)
 	/* Now let's do the physical EL1 timer irq */
 
 	if (info->physical_irq > 0) {
-		host_ptimer_irq = info->physical_irq;
-		host_ptimer_irq_flags = irq_get_trigger_type(host_ptimer_irq);
-		if (host_ptimer_irq_flags != IRQF_TRIGGER_HIGH &&
-		    host_ptimer_irq_flags != IRQF_TRIGGER_LOW) {
-			kvm_err("Invalid trigger for ptimer IRQ%d, assuming level low\n",
-				host_ptimer_irq);
-			host_ptimer_irq_flags = IRQF_TRIGGER_LOW;
-		}
-
 		err = request_percpu_irq(host_ptimer_irq, kvm_arch_timer_handler,
 					 "kvm guest ptimer", kvm_get_running_vcpus());
 		if (err) {
-- 
2.29.2

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[PATCH v2 8/9] KVM: arm64: timer: Add support for SW-based deactivation

[Marc Zyngier]

In order to deal with the lack of active state, we need to use
the mask/unmask primitives (after all, the active state is just an
additional mask on top of the normal one).

To avoid adding a bunch of ugly conditionals in the timer and vgic
code, let's use a timer-specific irqdomain to deal with the state
conversion. Yes, this is an unexpected use of irqdomains, but
there is no reason not to be just as creative as the designers
of the HW...

This involves overloading the vcpu_affinity, set_irqchip_state
and eoi callbacks so that the rest of the KVM code can continue
ignoring the oddities of the underlying platform.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arch_timer.c | 100 ++++++++++++++++++++++++++++++++++--
 1 file changed, 96 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 7fa4f446456a..4c24cbb19ba1 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -9,6 +9,7 @@
 #include <linux/kvm_host.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/uaccess.h>
 
 #include <clocksource/arm_arch_timer.h>
@@ -973,6 +974,77 @@ static int kvm_timer_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
+static int timer_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu)
+{
+	if (vcpu)
+		irqd_set_forwarded_to_vcpu(d);
+	else
+		irqd_clr_forwarded_to_vcpu(d);
+
+	return 0;
+}
+
+static int timer_irq_set_irqchip_state(struct irq_data *d,
+				       enum irqchip_irq_state which, bool val)
+{
+	if (which != IRQCHIP_STATE_ACTIVE || !irqd_is_forwarded_to_vcpu(d))
+		return irq_chip_set_parent_state(d, which, val);
+
+	if (val)
+		irq_chip_mask_parent(d);
+	else
+		irq_chip_unmask_parent(d);
+
+	return 0;
+}
+
+static void timer_irq_eoi(struct irq_data *d)
+{
+	if (!irqd_is_forwarded_to_vcpu(d))
+		irq_chip_eoi_parent(d);
+}
+
+static void timer_irq_ack(struct irq_data *d)
+{
+	d = d->parent_data;
+	if (d->chip->irq_ack)
+		d->chip->irq_ack(d);
+}
+
+static struct irq_chip timer_chip = {
+	.name			= "KVM",
+	.irq_ack		= timer_irq_ack,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= timer_irq_eoi,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_set_vcpu_affinity	= timer_irq_set_vcpu_affinity,
+	.irq_set_irqchip_state	= timer_irq_set_irqchip_state,
+};
+
+static int timer_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs, void *arg)
+{
+	irq_hw_number_t hwirq = (uintptr_t)arg;
+
+	return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+					     &timer_chip, NULL);
+}
+
+static void timer_irq_domain_free(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs)
+{
+}
+
+static const struct irq_domain_ops timer_domain_ops = {
+	.alloc	= timer_irq_domain_alloc,
+	.free	= timer_irq_domain_free,
+};
+
+static struct irq_ops arch_timer_irq_ops = {
+	.get_input_level = kvm_arch_timer_get_input_level,
+};
+
 static void kvm_irq_fixup_flags(unsigned int virq, u32 *flags)
 {
 	*flags = irq_get_trigger_type(virq);
@@ -998,9 +1070,33 @@ static int kvm_irq_init(struct arch_timer_kvm_info *info)
 	host_vtimer_irq = info->virtual_irq;
 	kvm_irq_fixup_flags(host_vtimer_irq, &host_vtimer_irq_flags);
 
+	if (kvm_vgic_global_state.no_hw_deactivation) {
+		fwnode = irq_domain_alloc_named_fwnode("kvm-timer");
+		if (!fwnode)
+			return -ENOMEM;
+
+		/* Assume both vtimer and ptimer in the same parent */
+		data = irq_get_irq_data(host_vtimer_irq);
+		domain = irq_domain_create_hierarchy(data->domain, 0,
+						     NR_KVM_TIMERS, fwnode,
+						     &timer_domain_ops, NULL);
+		if (!domain) {
+			irq_domain_free_fwnode(fwnode);
+			return -ENOMEM;
+		}
+
+		arch_timer_irq_ops.flags |= VGIC_IRQ_SW_RESAMPLE;
+		WARN_ON(irq_domain_push_irq(domain, host_vtimer_irq,
+					    (void *)TIMER_VTIMER));
+	}
+
 	if (info->physical_irq > 0) {
 		host_ptimer_irq = info->physical_irq;
 		kvm_irq_fixup_flags(host_ptimer_irq, &host_ptimer_irq_flags);
+
+		if (domain)
+			WARN_ON(irq_domain_push_irq(domain, host_ptimer_irq,
+						    (void *)TIMER_PTIMER));
 	}
 
 	return 0;
@@ -1129,10 +1225,6 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	return kvm_timer_should_fire(timer);
 }
 
-static struct irq_ops arch_timer_irq_ops = {
-	.get_input_level = kvm_arch_timer_get_input_level,
-};
-
 int kvm_timer_enable(struct kvm_vcpu *vcpu)
 {
 	struct arch_timer_cpu *timer = vcpu_timer(vcpu);
-- 
2.29.2

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[PATCH v2 9/9] irqchip/apple-aic: Advertise some level of vGICv3 compatibility

[Marc Zyngier]

The CPUs in the Apple M1 SoC partially implement a virtual GICv3
CPU interface, although one that is incapable of HW deactivation
of interrupts.

Advertise the support to KVM.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/irqchip/irq-apple-aic.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
index ed16b6cc00d7..65067b2c746b 100644
--- a/drivers/irqchip/irq-apple-aic.c
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -50,6 +50,7 @@
 #include <linux/cpuhotplug.h>
 #include <linux/io.h>
 #include <linux/irqchip.h>
+#include <linux/irqchip/arm-vgic-info.h>
 #include <linux/irqdomain.h>
 #include <linux/limits.h>
 #include <linux/of_address.h>
@@ -772,6 +773,11 @@ static int aic_init_cpu(unsigned int cpu)
 	return 0;
 }
 
+static struct gic_kvm_info vgic_info __initdata = {
+	.type			= GIC_V3,
+	.no_hw_deactivation	= true,
+};
+
 static int __init aic_of_ic_init(struct device_node *node, struct device_node *parent)
 {
 	int i;
@@ -828,6 +834,8 @@ static int __init aic_of_ic_init(struct device_node *node, struct device_node *p
 			  "irqchip/apple-aic/ipi:starting",
 			  aic_init_cpu, NULL);
 
+	vgic_set_kvm_info(&vgic_info);
+
 	pr_info("Initialized with %d IRQs, %d FIQs, %d vIPIs\n",
 		irqc->nr_hw, AIC_NR_FIQ, AIC_NR_SWIPI);
 
-- 
2.29.2

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