[PATCH 76/89] KVM: arm64: Factor out vcpu_reset code for core registers and PSCI

From: Will Deacon <will@kernel.org>
To: kvmarm@lists.cs.columbia.edu
Cc: Marc Zyngier <maz@kernel.org>,
	kernel-team@android.com, kvm@vger.kernel.org,
	Andy Lutomirski <luto@amacapital.net>,
	linux-arm-kernel@lists.infradead.org,
	Michael Roth <michael.roth@amd.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Chao Peng <chao.p.peng@linux.intel.com>,
	Will Deacon <will@kernel.org>
Subject: [PATCH 76/89] KVM: arm64: Factor out vcpu_reset code for core registers and PSCI
Date: Thu, 19 May 2022 14:41:51 +0100	[thread overview]
Message-ID: <20220519134204.5379-77-will@kernel.org> (raw)
In-Reply-To: <20220519134204.5379-1-will@kernel.org>

From: Fuad Tabba <tabba@google.com>

Factor out logic that resets a vcpu's core registers, including
additional PSCI handling. This code will be reused when resetting
VMs in protected mode.

Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/include/asm/kvm_emulate.h | 41 +++++++++++++++++++++++++
 arch/arm64/kvm/reset.c               | 45 +++++-----------------------
 2 files changed, 48 insertions(+), 38 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 82515b015eb4..2a79c861b8e0 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -522,4 +522,45 @@ static inline unsigned long psci_affinity_mask(unsigned long affinity_level)
 	return 0;
 }
 
+/* Reset a vcpu's core registers. */
+static inline void kvm_reset_vcpu_core(struct kvm_vcpu *vcpu)
+{
+	u32 pstate;
+
+	if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
+		pstate = VCPU_RESET_PSTATE_SVC;
+	} else {
+		pstate = VCPU_RESET_PSTATE_EL1;
+	}
+
+	/* Reset core registers */
+	memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
+	memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
+	vcpu->arch.ctxt.spsr_abt = 0;
+	vcpu->arch.ctxt.spsr_und = 0;
+	vcpu->arch.ctxt.spsr_irq = 0;
+	vcpu->arch.ctxt.spsr_fiq = 0;
+	vcpu_gp_regs(vcpu)->pstate = pstate;
+}
+
+/* PSCI reset handling for a vcpu. */
+static inline void kvm_reset_vcpu_psci(struct kvm_vcpu *vcpu,
+				       struct vcpu_reset_state *reset_state)
+{
+	unsigned long target_pc = reset_state->pc;
+
+	/* Gracefully handle Thumb2 entry point */
+	if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
+		target_pc &= ~1UL;
+		vcpu_set_thumb(vcpu);
+	}
+
+	/* Propagate caller endianness */
+	if (reset_state->be)
+		kvm_vcpu_set_be(vcpu);
+
+	*vcpu_pc(vcpu) = target_pc;
+	vcpu_set_reg(vcpu, 0, reset_state->r0);
+}
+
 #endif /* __ARM64_KVM_EMULATE_H__ */
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 6bc979aece3c..4d223fae996d 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -109,7 +109,7 @@ static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
 		kfree(buf);
 		return ret;
 	}
-	
+
 	vcpu->arch.sve_state = buf;
 	vcpu->arch.flags |= KVM_ARM64_VCPU_SVE_FINALIZED;
 	return 0;
@@ -202,7 +202,6 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	struct vcpu_reset_state reset_state;
 	int ret;
 	bool loaded;
-	u32 pstate;
 
 	mutex_lock(&vcpu->kvm->lock);
 	reset_state = vcpu->arch.reset_state;
@@ -240,29 +239,13 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 		goto out;
 	}
 
-	switch (vcpu->arch.target) {
-	default:
-		if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
-			pstate = VCPU_RESET_PSTATE_SVC;
-		} else {
-			pstate = VCPU_RESET_PSTATE_EL1;
-		}
-
-		if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) {
-			ret = -EINVAL;
-			goto out;
-		}
-		break;
+	if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) {
+		ret = -EINVAL;
+		goto out;
 	}
 
 	/* Reset core registers */
-	memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
-	memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
-	vcpu->arch.ctxt.spsr_abt = 0;
-	vcpu->arch.ctxt.spsr_und = 0;
-	vcpu->arch.ctxt.spsr_irq = 0;
-	vcpu->arch.ctxt.spsr_fiq = 0;
-	vcpu_gp_regs(vcpu)->pstate = pstate;
+	kvm_reset_vcpu_core(vcpu);
 
 	/* Reset system registers */
 	kvm_reset_sys_regs(vcpu);
@@ -271,22 +254,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	 * Additional reset state handling that PSCI may have imposed on us.
 	 * Must be done after all the sys_reg reset.
 	 */
-	if (reset_state.reset) {
-		unsigned long target_pc = reset_state.pc;
-
-		/* Gracefully handle Thumb2 entry point */
-		if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
-			target_pc &= ~1UL;
-			vcpu_set_thumb(vcpu);
-		}
-
-		/* Propagate caller endianness */
-		if (reset_state.be)
-			kvm_vcpu_set_be(vcpu);
-
-		*vcpu_pc(vcpu) = target_pc;
-		vcpu_set_reg(vcpu, 0, reset_state.r0);
-	}
+	if (reset_state.reset)
+		kvm_reset_vcpu_psci(vcpu, &reset_state);
 
 	/* Reset timer */
 	ret = kvm_timer_vcpu_reset(vcpu);
-- 
2.36.1.124.g0e6072fb45-goog

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