From 3fe72e213eae33daaea88685878a571bd5ef3e08 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 19 Aug 2022 12:00:51 +0100 Subject: target/arm: Advertise FEAT_ETS for '-cpu max' The architectural feature FEAT_ETS (Enhanced Translation Synchronization) is a set of tightened guarantees about memory ordering involving translation table walks: * if memory access RW1 is ordered-before memory access RW2 then it is also ordered-before any translation table walk generated by RW2 that generates a translation fault, address size fault or access fault * TLB maintenance on non-exec-permission translations is guaranteed complete after a DSB (ie it does not need the context synchronization event that you have to have if you don’t have FEAT_ETS) For QEMU’s implementation we don’t reorder translation table walk accesses, and we guarantee to finish the TLB maintenance as soon as the TLB op is done (the tlb_flush functions will complete at the end of the TLB, and TLB ops always end the TB because they’re sysreg writes). So we’re already compliant and all we need to do is say so in the ID registers for the 'max' CPU. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-Id: <20220819110052.2942289-6-peter.maydell@linaro.org> Signed-off-by: Richard Henderson --- docs/system/arm/emulation.rst | 1 + 1 file changed, 1 insertion(+) (limited to 'docs') diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst index 8e494c8bea..811358fd0a 100644 --- a/docs/system/arm/emulation.rst +++ b/docs/system/arm/emulation.rst @@ -24,6 +24,7 @@ the following architecture extensions: - FEAT_Debugv8p4 (Debug changes for v8.4) - FEAT_DotProd (Advanced SIMD dot product instructions) - FEAT_DoubleFault (Double Fault Extension) +- FEAT_ETS (Enhanced Translation Synchronization) - FEAT_FCMA (Floating-point complex number instructions) - FEAT_FHM (Floating-point half-precision multiplication instructions) - FEAT_FP16 (Half-precision floating-point data processing) -- cgit v1.2.3-55-g7522