linux-kernel - [PATCH v3 2/6] KVM: LoongArch: selftests: Add basic interfaces

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Message-Id: <20251120065758.3064368-3-maobibo@loongson.cn>
Date: Thu, 20 Nov 2025 14:57:54 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Paolo Bonzini <pbonzini@...hat.com>,
	Sean Christopherson <seanjc@...gle.com>,
	Huacai Chen <chenhuacai@...nel.org>,
	Tianrui Zhao <zhaotianrui@...ngson.cn>,
	Shuah Khan <shuah@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linux-kselftest@...r.kernel.org
Subject: [PATCH v3 2/6] KVM: LoongArch: selftests: Add basic interfaces

Add some basic function interfaces such as CSR register access,
local irq enable or disable APIs.

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 .../kvm/include/loongarch/processor.h         | 52 +++++++++++++++++++
 .../selftests/kvm/lib/loongarch/processor.c   |  5 ++
 2 files changed, 57 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/loongarch/processor.h b/tools/testing/selftests/kvm/include/loongarch/processor.h
index 374caddfb0db..0bf120d23092 100644
--- a/tools/testing/selftests/kvm/include/loongarch/processor.h
+++ b/tools/testing/selftests/kvm/include/loongarch/processor.h
@@ -113,6 +113,28 @@
 #define  CSR_TLBREHI_PS_SHIFT		0
 #define  CSR_TLBREHI_PS			(0x3fUL << CSR_TLBREHI_PS_SHIFT)
 
+#define csr_read(csr)				\
+({						\
+	register unsigned long __v;		\
+	__asm__ __volatile__(			\
+		"csrrd %[val], %[reg]\n\t"	\
+		: [val] "=r" (__v)		\
+		: [reg] "i" (csr)		\
+		: "memory");			\
+	__v;					\
+})
+
+#define csr_write(v, csr)			\
+({						\
+	register unsigned long __v = v;		\
+	__asm__ __volatile__ (			\
+		"csrwr %[val], %[reg]\n\t"	\
+		: [val] "+r" (__v)		\
+		: [reg] "i" (csr)		\
+		: "memory");			\
+	__v;					\
+})
+
 #define EXREGS_GPRS			(32)
 
 #ifndef __ASSEMBLER__
@@ -133,6 +155,36 @@ struct ex_regs {
 #define PRMD_OFFSET_EXREGS		offsetof(struct ex_regs, prmd)
 #define EXREGS_SIZE			sizeof(struct ex_regs)
 
+static inline void local_irq_enable(void)
+{
+	unsigned int flags = CSR_CRMD_IE;
+
+	register unsigned int mask asm("$t0") = CSR_CRMD_IE;
+
+	__asm__ __volatile__(
+		"csrxchg %[val], %[mask], %[reg]\n\t"
+		: [val] "+r" (flags)
+		: [mask] "r" (mask), [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+}
+
+static inline void local_irq_disable(void)
+{
+	unsigned int flags = 0;
+
+	register unsigned int mask asm("$t0") = CSR_CRMD_IE;
+
+	__asm__ __volatile__(
+		"csrxchg %[val], %[mask], %[reg]\n\t"
+		: [val] "+r" (flags)
+		: [mask] "r" (mask), [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+}
+
+static inline void cpu_relax(void)
+{
+	asm volatile("nop" ::: "memory");
+}
 #else
 #define PC_OFFSET_EXREGS		((EXREGS_GPRS + 0) * 8)
 #define ESTAT_OFFSET_EXREGS		((EXREGS_GPRS + 1) * 8)
diff --git a/tools/testing/selftests/kvm/lib/loongarch/processor.c b/tools/testing/selftests/kvm/lib/loongarch/processor.c
index 0ac1abcb71cb..5b5f09acf229 100644
--- a/tools/testing/selftests/kvm/lib/loongarch/processor.c
+++ b/tools/testing/selftests/kvm/lib/loongarch/processor.c
@@ -344,3 +344,8 @@ void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
 	regs.pc = (uint64_t)guest_code;
 	vcpu_regs_set(vcpu, &regs);
 }
+
+uint32_t guest_get_vcpuid(void)
+{
+	return csr_read(LOONGARCH_CSR_CPUID);
+}
-- 
2.39.3