[PATCH v3 0/1] target/riscv: Add Zihintntl extension ISA string to DTS

[PATCH v3 0/1] target/riscv: Add Zihintntl extension ISA string to DTS

[Jason Chien]

In v2, I rebased the patch on
https://github.com/alistair23/qemu/tree/riscv-to-apply.next
However, I forgot to add "Reviewed-by" in v2, so I add them in v3.

Jason Chien (1):
  target/riscv: Add Zihintntl extension ISA string to DTS

 target/riscv/cpu.c     | 2 ++
 target/riscv/cpu_cfg.h | 1 +
 2 files changed, 3 insertions(+)

-- 
2.17.1

[PATCH v3 1/1] target/riscv: Add Zihintntl extension ISA string to DTS

[Jason Chien]

RVA23 Profiles states:
The RVA23 profiles are intended to be used for 64-bit application
processors that will run rich OS stacks from standard binary OS
distributions and with a substantial number of third-party binary user
applications that will be supported over a considerable length of time
in the field.

The chapter 4 of the unprivileged spec introduces the Zihintntl extension
and Zihintntl is a mandatory extension presented in RVA23 Profiles, whose
purpose is to enable application and operating system portability across
different implementations. Thus the DTS should contain the Zihintntl ISA
string in order to pass to software.

The unprivileged spec states:
Like any HINTs, these instructions may be freely ignored. Hence, although
they are described in terms of cache-based memory hierarchies, they do not
mandate the provision of caches.

These instructions are encoded with used opcode, e.g. ADD x0, x0, x2, which
QEMU already supports, and QEMU does not emulate cache. Therefore these
instructions can be considered as a no-op, and we only need to add a new
property for the Zihintntl extension.

Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Jason Chien <jason.chien@sifive.com>
---
 target/riscv/cpu.c     | 2 ++
 target/riscv/cpu_cfg.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 9339c0241d..b7e99cccd9 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -87,6 +87,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zicond, PRIV_VERSION_1_12_0, ext_zicond),
     ISA_EXT_DATA_ENTRY(zicsr, PRIV_VERSION_1_10_0, ext_icsr),
     ISA_EXT_DATA_ENTRY(zifencei, PRIV_VERSION_1_10_0, ext_ifencei),
+    ISA_EXT_DATA_ENTRY(zihintntl, PRIV_VERSION_1_10_0, ext_zihintntl),
     ISA_EXT_DATA_ENTRY(zihintpause, PRIV_VERSION_1_10_0, ext_zihintpause),
     ISA_EXT_DATA_ENTRY(zawrs, PRIV_VERSION_1_12_0, ext_zawrs),
     ISA_EXT_DATA_ENTRY(zfa, PRIV_VERSION_1_12_0, ext_zfa),
@@ -1755,6 +1756,7 @@ static Property riscv_cpu_extensions[] = {
     DEFINE_PROP_BOOL("sscofpmf", RISCVCPU, cfg.ext_sscofpmf, false),
     DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true),
     DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true),
+    DEFINE_PROP_BOOL("Zihintntl", RISCVCPU, cfg.ext_zihintntl, true),
     DEFINE_PROP_BOOL("Zihintpause", RISCVCPU, cfg.ext_zihintpause, true),
     DEFINE_PROP_BOOL("Zawrs", RISCVCPU, cfg.ext_zawrs, true),
     DEFINE_PROP_BOOL("Zfa", RISCVCPU, cfg.ext_zfa, true),
diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index 2bd9510ba3..518686eaa3 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -66,6 +66,7 @@ struct RISCVCPUConfig {
     bool ext_icbom;
     bool ext_icboz;
     bool ext_zicond;
+    bool ext_zihintntl;
     bool ext_zihintpause;
     bool ext_smstateen;
     bool ext_sstc;
-- 
2.17.1