From 6e0c60a2be30c333b06d3558a62b0f177199cbfb Mon Sep 17 00:00:00 2001 From: Jamie Iles Date: Wed, 26 May 2021 13:18:44 +0100 Subject: [PATCH] target/arm: fix missing exception class MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The DAIF and PAC checks used raise_exception_ra to raise an exception and unwind CPU state but raise_exception_ra is currently designed for handling data aborts as the syndrome is partially precomputed and encoded in the TB and then merged in merge_syn_data_abort when handling the data abort. Using raise_exception_ra for DAIF and PAC checks results in an empty syndrome being retrieved from data[2] in restore_state_to_opc and setting ESR to 0. This manifested as: kvm [571]: Unknown exception class: esr: 0x000000 – Unknown/Uncategorized when launching a KVM guest when the host qemu used a CPU supporting EL2+pointer authentication and enabling pointer authentication in the guest. Rework raise_exception_ra such that the state is restored before raising the exception so that the exception is not clobbered by restore_state_to_opc. Fixes: 0d43e1a2d29a ("target/arm: Add PAuth helpers") Cc: Richard Henderson Cc: Peter Maydell Signed-off-by: Jamie Iles [PMM: added comment] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- target/arm/op_helper.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index efcb600992..1a95972bcc 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -63,8 +63,15 @@ void raise_exception(CPUARMState *env, uint32_t excp, void raise_exception_ra(CPUARMState *env, uint32_t excp, uint32_t syndrome, uint32_t target_el, uintptr_t ra) { - CPUState *cs = do_raise_exception(env, excp, syndrome, target_el); - cpu_loop_exit_restore(cs, ra); + CPUState *cs = env_cpu(env); + + /* + * restore_state_to_opc() will set env->exception.syndrome, so + * we must restore CPU state here before setting the syndrome + * the caller passed us, and cannot use cpu_loop_exit_restore(). + */ + cpu_restore_state(cs, ra, true); + raise_exception(env, excp, syndrome, target_el); } uint64_t HELPER(neon_tbl)(CPUARMState *env, uint32_t desc,