Received-SPF: pass (google.com: domain of linux-kernel+bounces-109818-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: Anup Patel <apatel@ventanamicro.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Atish Patra <atishp@atishpatra.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Andrew Jones <ajones@ventanamicro.com>,
	Anup Patel <anup@brainfault.org>,
	kvm@vger.kernel.org,
	kvm-riscv@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Anup Patel <apatel@ventanamicro.com>
Subject: [PATCH 2/2] RISC-V: KVM: Fix APLIC in_clrip[x] read emulation
Date: Thu, 21 Mar 2024 14:20:41 +0530
Message-Id: <20240321085041.1955293-3-apatel@ventanamicro.com>
In-Reply-To: <20240321085041.1955293-1-apatel@ventanamicro.com>
References: <20240321085041.1955293-1-apatel@ventanamicro.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The reads to APLIC in_clrip[x] registers returns rectified input values
of the interrupt sources.

A rectified input value of an interrupt source is defined by the section
"4.5.2 Source configurations (sourcecfg[1]–sourcecfg[1023])" of the
RISC-V AIA specification as:

    rectified input value = (incoming wire value) XOR (source is inverted)

Update the riscv_aplic_input() implementation to match the above.

Fixes: 74967aa208e2 ("RISC-V: KVM: Add in-kernel emulation of AIA APLIC")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 arch/riscv/kvm/aia_aplic.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kvm/aia_aplic.c b/arch/riscv/kvm/aia_aplic.c
index 5e842b92dc46..b467ba5ed910 100644
--- a/arch/riscv/kvm/aia_aplic.c
+++ b/arch/riscv/kvm/aia_aplic.c
@@ -197,16 +197,31 @@ static void aplic_write_enabled(struct aplic *aplic, u32 irq, bool enabled)
 
 static bool aplic_read_input(struct aplic *aplic, u32 irq)
 {
-	bool ret;
-	unsigned long flags;
+	u32 sourcecfg, sm, raw_input, irq_inverted;
 	struct aplic_irq *irqd;
+	unsigned long flags;
+	bool ret = false;
 
 	if (!irq || aplic->nr_irqs <= irq)
 		return false;
 	irqd = &aplic->irqs[irq];
 
 	raw_spin_lock_irqsave(&irqd->lock, flags);
-	ret = (irqd->state & APLIC_IRQ_STATE_INPUT) ? true : false;
+
+	sourcecfg = irqd->sourcecfg;
+	if (sourcecfg & APLIC_SOURCECFG_D)
+		goto skip;
+
+	sm = sourcecfg & APLIC_SOURCECFG_SM_MASK;
+	if (sm == APLIC_SOURCECFG_SM_INACTIVE)
+		goto skip;
+
+	raw_input = (irqd->state & APLIC_IRQ_STATE_INPUT) ? 1 : 0;
+	irq_inverted = (sm == APLIC_SOURCECFG_SM_LEVEL_LOW ||
+			sm == APLIC_SOURCECFG_SM_EDGE_FALL) ? 1 : 0;
+	ret = !!(raw_input ^ irq_inverted);
+
+skip:
 	raw_spin_unlock_irqrestore(&irqd->lock, flags);
 
 	return ret;
-- 
2.34.1