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[PULL,08/21] target/arm: Enable FEAT_Spec_FPACC for -cpu max

Message ID 20240430164842.4074734-9-peter.maydell@linaro.org
State Accepted
Commit 663163f00785805e61f524ef744914029b2b6a87
Headers show
Series [PULL,01/21] hw/core/clock: allow clock_propagate on child clocks | expand

Commit Message

Peter Maydell April 30, 2024, 4:48 p.m. UTC 
FEAT_Spec_FPACC is a feature describing speculative behaviour in the
event of a PAC authontication failure when FEAT_FPACCOMBINE is
implemented.  FEAT_Spec_FPACC means that the speculative use of
pointers processed by a PAC Authentication is not materially
different in terms of the impact on cached microarchitectural state
(caches, TLBs, etc) between passing and failing of the PAC
Authentication.

QEMU doesn't do speculative execution, so we can advertise
this feature.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20240418152004.2106516-6-peter.maydell@linaro.org
---
 docs/system/arm/emulation.rst | 1 +
 target/arm/tcg/cpu64.c        | 4 ++++
 2 files changed, 5 insertions(+)
diff mbox series

Patch

diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index 307539cff91..7fcea54d8db 100644
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -61,6 +61,7 @@  the following architecture extensions:
 - FEAT_FP16 (Half-precision floating-point data processing)
 - FEAT_FPAC (Faulting on AUT* instructions)
 - FEAT_FPACCOMBINE (Faulting on combined pointer authentication instructions)
+- FEAT_FPACC_SPEC (Speculative behavior of combined pointer authentication instructions)
 - FEAT_FRINTTS (Floating-point to integer instructions)
 - FEAT_FlagM (Flag manipulation instructions v2)
 - FEAT_FlagM2 (Enhancements to flag manipulation instructions)
diff --git a/target/arm/tcg/cpu64.c b/target/arm/tcg/cpu64.c
index ebb585afd85..443cffe3a85 100644
--- a/target/arm/tcg/cpu64.c
+++ b/target/arm/tcg/cpu64.c
@@ -1217,6 +1217,10 @@  void aarch64_max_tcg_initfn(Object *obj)
     t = FIELD_DP64(t, ID_AA64MMFR2, E0PD, 1);     /* FEAT_E0PD */
     cpu->isar.id_aa64mmfr2 = t;
 
+    t = cpu->isar.id_aa64mmfr3;
+    t = FIELD_DP64(t, ID_AA64MMFR3, SPEC_FPACC, 1); /* FEAT_FPACC_SPEC */
+    cpu->isar.id_aa64mmfr3 = t;
+
     t = cpu->isar.id_aa64zfr0;
     t = FIELD_DP64(t, ID_AA64ZFR0, SVEVER, 1);
     t = FIELD_DP64(t, ID_AA64ZFR0, AES, 2);       /* FEAT_SVE_PMULL128 */