From: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

QEMU already implements zicbom (Cache Block Management Operations) and
zicboz (Cache Block Zero Operations). Commit 59cb29d6a5 ("target/riscv:
add Zicbop cbo.prefetch{i, r, m} placeholder") added placeholders for
what would be the instructions for zicbop (Cache Block Prefetch
Operations), which are now no-ops.

The RVA22U64 profile mandates zicbop, which means that applications that
run with this profile might expect zicbop to be present in the riscv,isa
DT and might behave badly if it's absent.

Adding zicbop as an extension will make our future RVA22U64
implementation more in line with what userspace expects and, if/when
cache block prefetch operations became relevant to QEMU, we already have
the extension flag to turn then on/off as needed.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231218125334.37184-6-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu_cfg.h | 2 ++
 hw/riscv/virt.c        | 5 +++++
 target/riscv/cpu.c     | 3 +++
 3 files changed, 10 insertions(+)

diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index d516de4a44..2da8ac9582 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -65,6 +65,7 @@ struct RISCVCPUConfig {
     bool ext_zicntr;
     bool ext_zicsr;
     bool ext_zicbom;
+    bool ext_zicbop;
     bool ext_zicboz;
     bool ext_zicond;
     bool ext_zihintntl;
@@ -143,6 +144,7 @@ struct RISCVCPUConfig {
     uint16_t vlen;
     uint16_t elen;
     uint16_t cbom_blocksize;
+    uint16_t cbop_blocksize;
     uint16_t cboz_blocksize;
     bool mmu;
     bool pmp;
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index 4194ddcef1..f9fd1341fc 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -250,6 +250,11 @@ static void create_fdt_socket_cpus(RISCVVirtState *s, int socket,
                                   cpu_ptr->cfg.cboz_blocksize);
         }
 
+        if (cpu_ptr->cfg.ext_zicbop) {
+            qemu_fdt_setprop_cell(ms->fdt, cpu_name, "riscv,cbop-block-size",
+                                  cpu_ptr->cfg.cbop_blocksize);
+        }
+
         qemu_fdt_setprop_string(ms->fdt, cpu_name, "compatible", "riscv");
         qemu_fdt_setprop_string(ms->fdt, cpu_name, "status", "okay");
         qemu_fdt_setprop_cell(ms->fdt, cpu_name, "reg",
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 33d25d12a6..ce0a3ded04 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -78,6 +78,7 @@ const uint32_t misa_bits[] = {RVI, RVE, RVM, RVA, RVF, RVD, RVV,
  */
 const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zicbom, PRIV_VERSION_1_12_0, ext_zicbom),
+    ISA_EXT_DATA_ENTRY(zicbop, PRIV_VERSION_1_12_0, ext_zicbop),
     ISA_EXT_DATA_ENTRY(zicboz, PRIV_VERSION_1_12_0, ext_zicboz),
     ISA_EXT_DATA_ENTRY(zicond, PRIV_VERSION_1_12_0, ext_zicond),
     ISA_EXT_DATA_ENTRY(zicntr, PRIV_VERSION_1_12_0, ext_zicntr),
@@ -1375,6 +1376,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
     MULTI_EXT_CFG_BOOL("zhinxmin", ext_zhinxmin, false),
 
     MULTI_EXT_CFG_BOOL("zicbom", ext_zicbom, true),
+    MULTI_EXT_CFG_BOOL("zicbop", ext_zicbop, true),
     MULTI_EXT_CFG_BOOL("zicboz", ext_zicboz, true),
 
     MULTI_EXT_CFG_BOOL("zmmul", ext_zmmul, false),
@@ -1509,6 +1511,7 @@ Property riscv_cpu_options[] = {
     DEFINE_PROP_UINT16("elen", RISCVCPU, cfg.elen, 64),
 
     DEFINE_PROP_UINT16("cbom_blocksize", RISCVCPU, cfg.cbom_blocksize, 64),
+    DEFINE_PROP_UINT16("cbop_blocksize", RISCVCPU, cfg.cbop_blocksize, 64),
     DEFINE_PROP_UINT16("cboz_blocksize", RISCVCPU, cfg.cboz_blocksize, 64),
 
     DEFINE_PROP_END_OF_LIST(),
-- 
2.43.0