[PATCH 15/18] KVM: arm64: Warn when PENDING_EXCEPTION and INCREMENT_PC are set together

[Marc Zyngier <maz@kernel.org>]

We really don't want PENDING_EXCEPTION and INCREMENT_PC to ever be
set at the same time, as they are mutually exclusive. Add checks
that will generate a warning should this ever happen.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_emulate.h | 1 +
 arch/arm64/kvm/hyp/nvhe/sys_regs.c   | 2 ++
 arch/arm64/kvm/inject_fault.c        | 8 ++++++++
 3 files changed, 11 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 46e631cd8d9e..861fa0b24a7f 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -473,6 +473,7 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
 
 static __always_inline void kvm_incr_pc(struct kvm_vcpu *vcpu)
 {
+	WARN_ON(vcpu_get_flag(vcpu, PENDING_EXCEPTION));
 	vcpu_set_flag(vcpu, INCREMENT_PC);
 }
 
diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index 2841a2d447a1..04973984b6db 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -38,6 +38,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
 	*vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
 	*vcpu_cpsr(vcpu) = read_sysreg_el2(SYS_SPSR);
 
+	WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
+
 	vcpu_set_flag(vcpu, PENDING_EXCEPTION);
 	vcpu_set_flag(vcpu, EXCEPT_AA64_EL1_SYNC);
 
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index a9a7b513f3b0..2f4b9afc16ec 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -20,6 +20,8 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
 	bool is_aarch32 = vcpu_mode_is_32bit(vcpu);
 	u32 esr = 0;
 
+	WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
+
 	vcpu_set_flag(vcpu, PENDING_EXCEPTION);
 	vcpu_set_flag(vcpu, EXCEPT_AA64_EL1_SYNC);
 
@@ -51,6 +53,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
 {
 	u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
 
+	WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
+
 	vcpu_set_flag(vcpu, PENDING_EXCEPTION);
 	vcpu_set_flag(vcpu, EXCEPT_AA64_EL1_SYNC);
 
@@ -71,6 +75,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
 
 static void inject_undef32(struct kvm_vcpu *vcpu)
 {
+	WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
+
 	vcpu_set_flag(vcpu, PENDING_EXCEPTION);
 	vcpu_set_flag(vcpu, EXCEPT_AA32_UND);
 }
@@ -94,6 +100,8 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt, u32 addr)
 
 	far = vcpu_read_sys_reg(vcpu, FAR_EL1);
 
+	WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
+
 	if (is_pabt) {
 		vcpu_set_flag(vcpu, PENDING_EXCEPTION);
 		vcpu_set_flag(vcpu, EXCEPT_AA32_IABT);
-- 
2.34.1

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