From 903dbefc2b6918c10d12d9aafa0168cee8d287c7 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 12 Sep 2023 15:04:23 +0100 Subject: [PATCH] target/arm: Don't skip MTE checks for LDRT/STRT at EL0 The LDRT/STRT "unprivileged load/store" instructions behave like normal ones if executed at EL0. We handle this correctly for the load/store semantics, but get the MTE checking wrong. We always look at s->mte_active[is_unpriv] to see whether we should be doing MTE checks, but in hflags.c when we set the TB flags that will be used to fill the mte_active[] array we only set the MTE0_ACTIVE bit if UNPRIV is true (i.e. we are not at EL0). This means that a LDRT at EL0 will see s->mte_active[1] as 0, and will not do MTE checks even when MTE is enabled. To avoid the translate-time code having to do an explicit check on s->unpriv to see if it is OK to index into the mte_active[] array, duplicate MTE_ACTIVE into MTE0_ACTIVE when UNPRIV is false. (This isn't a very serious bug because generally nobody executes LDRT/STRT at EL0, because they have no use there.) Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20230912140434.1333369-2-peter.maydell@linaro.org --- target/arm/tcg/hflags.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/target/arm/tcg/hflags.c b/target/arm/tcg/hflags.c index 616c5fa723..ea642384f5 100644 --- a/target/arm/tcg/hflags.c +++ b/target/arm/tcg/hflags.c @@ -306,6 +306,15 @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState *env, int el, int fp_el, && !(env->pstate & PSTATE_TCO) && (sctlr & (el == 0 ? SCTLR_TCF0 : SCTLR_TCF))) { DP_TBFLAG_A64(flags, MTE_ACTIVE, 1); + if (!EX_TBFLAG_A64(flags, UNPRIV)) { + /* + * In non-unpriv contexts (eg EL0), unpriv load/stores + * act like normal ones; duplicate the MTE info to + * avoid translate-a64.c having to check UNPRIV to see + * whether it is OK to index into MTE_ACTIVE[]. + */ + DP_TBFLAG_A64(flags, MTE0_ACTIVE, 1); + } } } /* And again for unprivileged accesses, if required. */