From c22588c99635ac4dace0ce2d55c1e2dc4f13cb54 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 13 Oct 2020 11:56:50 +0100 Subject: [PATCH] KVM: arm64: Don't adjust PC on SError during SMC trap On SMC trap, the prefered return address is set to that of the SMC instruction itself. It is thus wrong to try and roll it back when an SError occurs while trapping on SMC. It is still necessary on HVC though, as HVC doesn't cause a trap, and sets ELR to returning *after* the HVC. It also became apparent that there is no 16bit encoding for an AArch32 HVC instruction, meaning that the displacement is always 4 bytes, no matter what the ISA is. Take this opportunity to simplify it. Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/kvm/handle_exit.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 5d690d6..79a7206 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -245,15 +245,15 @@ int handle_exit(struct kvm_vcpu *vcpu, int exception_index) u8 esr_ec = ESR_ELx_EC(kvm_vcpu_get_esr(vcpu)); /* - * HVC/SMC already have an adjusted PC, which we need - * to correct in order to return to after having - * injected the SError. + * HVC already have an adjusted PC, which we need to + * correct in order to return to after having injected + * the SError. + * + * SMC, on the other hand, is *trapped*, meaning its + * preferred return address is the SMC itself. */ - if (esr_ec == ESR_ELx_EC_HVC32 || esr_ec == ESR_ELx_EC_HVC64 || - esr_ec == ESR_ELx_EC_SMC32 || esr_ec == ESR_ELx_EC_SMC64) { - u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2; - *vcpu_pc(vcpu) -= adj; - } + if (esr_ec == ESR_ELx_EC_HVC32 || esr_ec == ESR_ELx_EC_HVC64) + *vcpu_pc(vcpu) -= 4; return 1; } -- 2.7.4