[PATCH 1/6] target/riscv/cpu.c: add zicntr extension flag

[Daniel Henrique Barboza <dbarboza@ventanamicro.com>]

zicntr is the Base Counters and Timers extension described in chapter 12
of the unprivileged spec. It describes support for RDCYCLE, RDTIME and
RDINSTRET.

QEMU already implements it way before it was a discrete extension.
zicntr is part of the RVA22 profile, so let's add it to QEMU to make the
future profile implementation flag complete.

Given than it represents an already existing feature, default it to
'true'. Change the realize() time validation to disable it in case its
dependency (icsr) isn't present.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
 target/riscv/cpu.c         | 7 +++++++
 target/riscv/cpu_cfg.h     | 1 +
 target/riscv/tcg/tcg-cpu.c | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 521bb88538..8783a415b1 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -79,6 +79,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zicbom, PRIV_VERSION_1_12_0, ext_icbom),
     ISA_EXT_DATA_ENTRY(zicboz, PRIV_VERSION_1_12_0, ext_icboz),
     ISA_EXT_DATA_ENTRY(zicond, PRIV_VERSION_1_12_0, ext_zicond),
+    ISA_EXT_DATA_ENTRY(zicntr, PRIV_VERSION_1_12_0, ext_icntr),
     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),
@@ -1265,6 +1266,12 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
     MULTI_EXT_CFG_BOOL("svnapot", ext_svnapot, false),
     MULTI_EXT_CFG_BOOL("svpbmt", ext_svpbmt, false),
 
+    /*
+     * Always default true - we'll disable it during
+     * realize() if needed.
+     */
+    MULTI_EXT_CFG_BOOL("zicntr", ext_icntr, true),
+
     MULTI_EXT_CFG_BOOL("zba", ext_zba, true),
     MULTI_EXT_CFG_BOOL("zbb", ext_zbb, true),
     MULTI_EXT_CFG_BOOL("zbc", ext_zbc, true),
diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index 0e6a0f245c..671b8c7cb8 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -62,6 +62,7 @@ struct RISCVCPUConfig {
     bool ext_zksh;
     bool ext_zkt;
     bool ext_ifencei;
+    bool ext_icntr;
     bool ext_icsr;
     bool ext_icbom;
     bool ext_icboz;
diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index a90ee63b06..ce0fde0f5d 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -542,6 +542,10 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, Error **errp)
         cpu_cfg_ext_auto_update(cpu, CPU_CFG_OFFSET(ext_zksh), true);
     }
 
+    if (cpu->cfg.ext_icntr && !cpu->cfg.ext_icsr) {
+        cpu->cfg.ext_icntr = false;
+    }
+
     /*
      * Disable isa extensions based on priv spec after we
      * validated and set everything we need.
-- 
2.41.0