Commit 0b3512fa authored Feb 06, 2018 by Marc Zyngier Committed by Greg Kroah-Hartman Feb 16, 2018

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 <christoffer.dall@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 402aeac5

arch/arm64/kvm/handle_exit.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}