From 0b3512fa7b0a4f1f187a5e38112c5bebaea87fc1 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 6 Feb 2018 17:56:07 +0000 Subject: [PATCH] arm64: KVM: Increment PC after handling an SMC trap Commit f5115e8869e1 upstream. When handling an SMC trap, the "preferred return address" is set to that of the SMC, and not the next PC (which is a departure from the behaviour of an SMC that isn't trapped). Increment PC in the handler, as the guest is otherwise forever stuck... Cc: stable@vger.kernel.org Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") Reviewed-by: Christoffer Dall Tested-by: Ard Biesheuvel Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kvm/handle_exit.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 380261e..7747f93 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -53,7 +53,16 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) { + /* + * "If an SMC instruction executed at Non-secure EL1 is + * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a + * Trap exception, not a Secure Monitor Call exception [...]" + * + * We need to advance the PC after the trap, as it would + * otherwise return to the same address... + */ vcpu_set_reg(vcpu, 0, ~0UL); + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); return 1; } -- 2.7.4