linux-kernel - [PATCH] LoongArch: KVM: Access mailbox directly in mail

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Message-Id: <20250731075907.189847-1-maobibo@loongson.cn>
Date: Thu, 31 Jul 2025 15:59:07 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Tianrui Zhao <zhaotianrui@...ngson.cn>,
	Huacai Chen <chenhuacai@...nel.org>,
	Xianglai Li <lixianglai@...ngson.cn>
Cc: kvm@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH] LoongArch: KVM: Access mailbox directly in mail_send()

With function mail_send(), it is to write mailbox of other VCPUs.
Existing simple APIs read_mailbox/write_mailbox can be used directly
rather than send command on IOCSR address.

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 arch/loongarch/kvm/intc/ipi.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c
index fe734dc062ed..832b2d4aa2ef 100644
--- a/arch/loongarch/kvm/intc/ipi.c
+++ b/arch/loongarch/kvm/intc/ipi.c
@@ -134,7 +134,8 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data)
 
 static int mail_send(struct kvm *kvm, uint64_t data)
 {
-	int cpu, mailbox, offset;
+	int i, cpu, mailbox, offset;
+	uint32_t val = 0, mask = 0;
 	struct kvm_vcpu *vcpu;
 
 	cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
@@ -144,9 +145,18 @@ static int mail_send(struct kvm *kvm, uint64_t data)
 		return -EINVAL;
 	}
 	mailbox = ((data & 0xffffffff) >> 2) & 0x7;
-	offset = IOCSR_IPI_BASE + IOCSR_IPI_BUF_20 + mailbox * 4;
+	offset = IOCSR_IPI_BUF_20 + mailbox * 4;
+	if ((data >> 27) & 0xf) {
+		val = read_mailbox(vcpu, offset, 4);
+		for (i = 0; i < 4; i++)
+			if (data & (BIT(27 + i)))
+				mask |= (0xff << (i * 8));
+		val &= mask;
+	}
 
-	return send_ipi_data(vcpu, offset, data);
+	val |= ((uint32_t)(data >> 32) & ~mask);
+	write_mailbox(vcpu, offset, val, 4);
+	return 0;
 }
 
 static int any_send(struct kvm *kvm, uint64_t data)

base-commit: 038d61fd642278bab63ee8ef722c50d10ab01e8f
-- 
2.39.3