linux-kernel - [PATCH 3/3] irqchip/apple-aic: Register vgic maintenance interrupt with KVM

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Message-Id: <20230103095022.3230946-4-maz@kernel.org>
Date:   Tue,  3 Jan 2023 09:50:22 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     <kvmarm@...ts.cs.columbia.edu>, <kvmarm@...ts.linux.dev>
Cc:     Hector Martin <marcan@...can.st>, Sven Peter <sven@...npeter.dev>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Thomas Gleixner <tglx@...utronix.de>,
        Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Oliver Upton <oliver.upton@...ux.dev>, asahi@...ts.linux.dev,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] irqchip/apple-aic: Register vgic maintenance interrupt with KVM

In order to deliver vgic maintenance interrupts that Nested Virt
requires, hook it into the FIQ space, even if it is delivered
as an IRQ (we don't distinguish between the two anyway).

Signed-off-by: Marc Zyngier <maz@...nel.org>
---
 drivers/irqchip/irq-apple-aic.c | 55 +++++++++++++++++++++++++--------
 1 file changed, 42 insertions(+), 13 deletions(-)

diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
index ae3437f03e6c..09fd52d91e45 100644
--- a/drivers/irqchip/irq-apple-aic.c
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -210,7 +210,6 @@
 				 FIELD_PREP(AIC_EVENT_NUM, x))
 #define AIC_HWIRQ_IRQ(x)	FIELD_GET(AIC_EVENT_NUM, x)
 #define AIC_HWIRQ_DIE(x)	FIELD_GET(AIC_EVENT_DIE, x)
-#define AIC_NR_FIQ		6
 #define AIC_NR_SWIPI		32
 
 /*
@@ -222,11 +221,18 @@
  * running at EL2 (with VHE). When the kernel is running at EL1, the
  * mapping differs and aic_irq_domain_translate() performs the remapping.
  */
-
-#define AIC_TMR_EL0_PHYS	AIC_TMR_HV_PHYS
-#define AIC_TMR_EL0_VIRT	AIC_TMR_HV_VIRT
-#define AIC_TMR_EL02_PHYS	AIC_TMR_GUEST_PHYS
-#define AIC_TMR_EL02_VIRT	AIC_TMR_GUEST_VIRT
+enum fiq_hwirq {
+	/* Must be ordered as in apple-aic.h */
+	AIC_TMR_EL0_PHYS	= AIC_TMR_HV_PHYS,
+	AIC_TMR_EL0_VIRT	= AIC_TMR_HV_VIRT,
+	AIC_TMR_EL02_PHYS	= AIC_TMR_GUEST_PHYS,
+	AIC_TMR_EL02_VIRT	= AIC_TMR_GUEST_VIRT,
+	AIC_CPU_PMU_Effi	= AIC_CPU_PMU_E,
+	AIC_CPU_PMU_Perf	= AIC_CPU_PMU_P,
+	/* No need for this to be discovered from DT */
+	AIC_VGIC_MI,
+	AIC_NR_FIQ
+};
 
 static DEFINE_STATIC_KEY_TRUE(use_fast_ipi);
 
@@ -384,14 +390,20 @@ static void __exception_irq_entry aic_handle_irq(struct pt_regs *regs)
 
 	/*
 	 * vGIC maintenance interrupts end up here too, so we need to check
-	 * for them separately. This should never trigger if KVM is working
-	 * properly, because it will have already taken care of clearing it
-	 * on guest exit before this handler runs.
+	 * for them separately. It should however only trigger when NV is
+	 * in use, and be cleared when coming back from the handler.
 	 */
-	if (is_kernel_in_hyp_mode() && (read_sysreg_s(SYS_ICH_HCR_EL2) & ICH_HCR_EN) &&
-		read_sysreg_s(SYS_ICH_MISR_EL2) != 0) {
-		pr_err_ratelimited("vGIC IRQ fired and not handled by KVM, disabling.\n");
-		sysreg_clear_set_s(SYS_ICH_HCR_EL2, ICH_HCR_EN, 0);
+	if (is_kernel_in_hyp_mode() &&
+	    (read_sysreg_s(SYS_ICH_HCR_EL2) & ICH_HCR_EN) &&
+	    read_sysreg_s(SYS_ICH_MISR_EL2) != 0) {
+		generic_handle_domain_irq(aic_irqc->hw_domain,
+					  AIC_FIQ_HWIRQ(AIC_VGIC_MI));
+
+		if (unlikely((read_sysreg_s(SYS_ICH_HCR_EL2) & ICH_HCR_EN) &&
+			     read_sysreg_s(SYS_ICH_MISR_EL2))) {
+			pr_err_ratelimited("vGIC IRQ fired and not handled by KVM, disabling.\n");
+			sysreg_clear_set_s(SYS_ICH_HCR_EL2, ICH_HCR_EN, 0);
+		}
 	}
 }
 
@@ -1178,6 +1190,23 @@ static int __init aic_of_ic_init(struct device_node *node, struct device_node *p
 			  "irqchip/apple-aic/ipi:starting",
 			  aic_init_cpu, NULL);
 
+	if (is_kernel_in_hyp_mode()) {
+		struct irq_fwspec mi = {
+			.fwnode		= of_node_to_fwnode(node),
+			.param_count	= 3,
+			.param		= {
+				[0]	= AIC_FIQ, /* This is a lie */
+				[1]	= AIC_VGIC_MI,
+				[2]	= IRQ_TYPE_LEVEL_HIGH,
+			},
+		};
+
+		vgic_info.maint_irq = irq_domain_alloc_irqs(irqc->hw_domain,
+							    1, NUMA_NO_NODE,
+							    &mi);
+		WARN_ON(!vgic_info.maint_irq);
+	}
+
 	vgic_set_kvm_info(&vgic_info);
 
 	pr_info("Initialized with %d/%d IRQs * %d/%d die(s), %d FIQs, %d vIPIs",
-- 
2.34.1