linux-kernel - [PATCH 5/6] RISC-V: KVM: Add common kvm_riscv_vcpu

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Date:   Tue,  1 Feb 2022 13:52:26 +0530
From:   Anup Patel <apatel@...tanamicro.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Atish Patra <atishp@...shpatra.org>
Cc:     Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Alistair Francis <Alistair.Francis@....com>,
        Anup Patel <anup@...infault.org>, kvm@...r.kernel.org,
        kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Anup Patel <apatel@...tanamicro.com>
Subject: [PATCH 5/6] RISC-V: KVM: Add common kvm_riscv_vcpu_wfi() function

The wait for interrupt (WFI) instruction emulation can share the VCPU
halt logic with SBI HSM suspend emulation so this patch adds a common
kvm_riscv_vcpu_wfi() function for this purpose.

Signed-off-by: Anup Patel <apatel@...tanamicro.com>
---
 arch/riscv/include/asm/kvm_host.h |  1 +
 arch/riscv/kvm/vcpu_exit.c        | 22 ++++++++++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 99ef6a120617..78da839657e5 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -228,6 +228,7 @@ void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu);
 
 void __kvm_riscv_unpriv_trap(void);
 
+void kvm_riscv_vcpu_wfi(struct kvm_vcpu *vcpu);
 unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu,
 					 bool read_insn,
 					 unsigned long guest_addr,
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index 571f319e995a..aa8af129e4bb 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -144,12 +144,7 @@ static int system_opcode_insn(struct kvm_vcpu *vcpu,
 {
 	if ((insn & INSN_MASK_WFI) == INSN_MATCH_WFI) {
 		vcpu->stat.wfi_exit_stat++;
-		if (!kvm_arch_vcpu_runnable(vcpu)) {
-			srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
-			kvm_vcpu_halt(vcpu);
-			vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
-			kvm_clear_request(KVM_REQ_UNHALT, vcpu);
-		}
+		kvm_riscv_vcpu_wfi(vcpu);
 		vcpu->arch.guest_context.sepc += INSN_LEN(insn);
 		return 1;
 	}
@@ -453,6 +448,21 @@ static int stage2_page_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	return 1;
 }
 
+/**
+ * kvm_riscv_vcpu_wfi -- Emulate wait for interrupt (WFI) behaviour
+ *
+ * @vcpu: The VCPU pointer
+ */
+void kvm_riscv_vcpu_wfi(struct kvm_vcpu *vcpu)
+{
+	if (!kvm_arch_vcpu_runnable(vcpu)) {
+		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+		kvm_vcpu_halt(vcpu);
+		vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+		kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+	}
+}
+
 /**
  * kvm_riscv_vcpu_unpriv_read -- Read machine word from Guest memory
  *
-- 
2.25.1