From fd6c8c206fc5d0717b0433b191de0715122f33bb Mon Sep 17 00:00:00 2001 From: Dongjiu Geng Date: Tue, 17 Oct 2017 22:23:49 +0800 Subject: arm/arm64: KVM: set right LR register value for 32 bit guest when inject abort When a exception is trapped to EL2, hardware uses ELR_ELx to hold the current fault instruction address. If KVM wants to inject a abort to 32 bit guest, it needs to set the LR register for the guest to emulate this abort happened in the guest. Because ARM32 architecture is pipelined execution, so the LR value has an offset to the fault instruction address. The offsets applied to Link value for exceptions as shown below, which should be added for the ARM32 link register(LR). Table taken from ARMv8 ARM DDI0487B-B, table G1-10: Exception Offset, for PE state of: A32 T32 Undefined Instruction +4 +2 Prefetch Abort +4 +4 Data Abort +8 +8 IRQ or FIQ +4 +4 [ Removed unused variables in inject_abt to avoid compile warnings. -- Christoffer ] Cc: Signed-off-by: Dongjiu Geng Tested-by: Haibin Zhang Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/kvm/emulate.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/arm/kvm') diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c index 0064b86a2c87..30a13647c54c 100644 --- a/arch/arm/kvm/emulate.c +++ b/arch/arm/kvm/emulate.c @@ -227,7 +227,7 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu) u32 return_offset = (is_thumb) ? 2 : 4; kvm_update_psr(vcpu, UND_MODE); - *vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) - return_offset; + *vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) + return_offset; /* Branch to exception vector */ *vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset; @@ -239,10 +239,8 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu) */ static void inject_abt(struct kvm_vcpu *vcpu, bool is_pabt, unsigned long addr) { - unsigned long cpsr = *vcpu_cpsr(vcpu); - bool is_thumb = (cpsr & PSR_T_BIT); u32 vect_offset; - u32 return_offset = (is_thumb) ? 4 : 0; + u32 return_offset = (is_pabt) ? 4 : 8; bool is_lpae; kvm_update_psr(vcpu, ABT_MODE); -- cgit v1.2.3