Thread (139 messages) 139 messages, 5 authors, 2022-01-27
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[PATCH v5 43/69] KVM: arm64: nv: Introduce sys_reg_desc.forward_trap

From: Marc Zyngier <maz@kernel.org>
Date: 2021-11-29 20:46:44
Also in: kvm, kvmarm
Subsystem: arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers: Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds

From: Jintack Lim <redacted>

This introduces a function prototype to determine if we need to forward
system instruction traps to the virtual EL2. The implementation of
forward_trap functions for each system instruction will be added in
later patches.

Signed-off-by: Jintack Lim <redacted>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 8 ++++++++
 arch/arm64/kvm/sys_regs.h | 6 ++++++
 2 files changed, 14 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3922ecc00869..77f07f960d84 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2598,6 +2598,14 @@ static void perform_access(struct kvm_vcpu *vcpu,
 	 */
 	BUG_ON(!r->access);
 
+	/*
+	 * Forward this trap to the virtual EL2 if the guest hypervisor has
+	 * configured to trap the current instruction.
+	 */
+	if (nested_virt_in_use(vcpu) && r->forward_trap
+	    && unlikely(r->forward_trap(vcpu)))
+		return;
+
 	/* Skip instruction if instructed so */
 	if (likely(r->access(vcpu, params, r)))
 		kvm_incr_pc(vcpu);
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index d260c26b1834..267b2f37444c 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -72,6 +72,12 @@ struct sys_reg_desc {
 	int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
 			const struct kvm_one_reg *reg, void __user *uaddr);
 
+	/*
+	 * Forward the trap to the virtual EL2 if the guest hypervisor has
+	 * configured to trap the current instruction.
+	 */
+	bool (*forward_trap)(struct kvm_vcpu *vcpu);
+
 	/* Return mask of REG_* runtime visibility overrides */
 	unsigned int (*visibility)(const struct kvm_vcpu *vcpu,
 				   const struct sys_reg_desc *rd);
-- 
2.30.2


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