From 3d65b958c5463a1c06cac51b6474097ecdbb576e Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 9 Jan 2024 14:43:43 +0000 Subject: [PATCH] target/arm: Set CTR_EL0.{IDC,DIC} for the 'max' CPU The CTR_EL0 register has some bits which allow the implementation to tell the guest that it does not need to do cache maintenance for data-to-instruction coherence and instruction-to-data coherence. QEMU doesn't emulate caches and so our cache maintenance insns are all NOPs. We already have some models of specific CPUs where we set these bits (e.g. the Neoverse V1), but the 'max' CPU still uses the settings it inherits from Cortex-A57. Set the bits for 'max' as well, so the guest doesn't need to do unnecessary work. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Tested-by: Miguel Luis --- target/arm/tcg/cpu64.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/target/arm/tcg/cpu64.c b/target/arm/tcg/cpu64.c index fcda99e158..40e7a45166 100644 --- a/target/arm/tcg/cpu64.c +++ b/target/arm/tcg/cpu64.c @@ -1105,6 +1105,16 @@ void aarch64_max_tcg_initfn(Object *obj) u = FIELD_DP32(u, CLIDR_EL1, LOUU, 0); cpu->clidr = u; + /* + * Set CTR_EL0.DIC and IDC to tell the guest it doesnt' need to + * do any cache maintenance for data-to-instruction or + * instruction-to-guest coherence. (Our cache ops are nops.) + */ + t = cpu->ctr; + t = FIELD_DP64(t, CTR_EL0, IDC, 1); + t = FIELD_DP64(t, CTR_EL0, DIC, 1); + cpu->ctr = t; + t = cpu->isar.id_aa64isar0; t = FIELD_DP64(t, ID_AA64ISAR0, AES, 2); /* FEAT_PMULL */ t = FIELD_DP64(t, ID_AA64ISAR0, SHA1, 1); /* FEAT_SHA1 */