[PATCH v2] target: riscv: Add Svvptc extension support

[Alexandre Ghiti]

The Svvptc extension describes a uarch that does not cache invalid TLB
entries: that's the case for qemu so there is nothing particular to
implement other than the introduction of this extension.

Since qemu already exposes Svvptc behaviour, let's enable it by default
since it allows to drastically reduce the number of sfence.vma emitted
by S-mode.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
Changes in v2:
- Rebase on top of master
- Enable Svvptc by default

 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 c53b0d5b40..19421c8a45 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -192,6 +192,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(svinval, PRIV_VERSION_1_12_0, ext_svinval),
     ISA_EXT_DATA_ENTRY(svnapot, PRIV_VERSION_1_12_0, ext_svnapot),
     ISA_EXT_DATA_ENTRY(svpbmt, PRIV_VERSION_1_12_0, ext_svpbmt),
+    ISA_EXT_DATA_ENTRY(svvptc, PRIV_VERSION_1_12_0, ext_svvptc),
     ISA_EXT_DATA_ENTRY(xtheadba, PRIV_VERSION_1_11_0, ext_xtheadba),
     ISA_EXT_DATA_ENTRY(xtheadbb, PRIV_VERSION_1_11_0, ext_xtheadbb),
     ISA_EXT_DATA_ENTRY(xtheadbs, PRIV_VERSION_1_11_0, ext_xtheadbs),
@@ -1499,6 +1500,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
     MULTI_EXT_CFG_BOOL("svinval", ext_svinval, false),
     MULTI_EXT_CFG_BOOL("svnapot", ext_svnapot, false),
     MULTI_EXT_CFG_BOOL("svpbmt", ext_svpbmt, false),
+    MULTI_EXT_CFG_BOOL("svvptc", ext_svvptc, true),
 
     MULTI_EXT_CFG_BOOL("zicntr", ext_zicntr, true),
     MULTI_EXT_CFG_BOOL("zihpm", ext_zihpm, true),
diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index fb7eebde52..62612ae348 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -78,6 +78,7 @@ struct RISCVCPUConfig {
     bool ext_svinval;
     bool ext_svnapot;
     bool ext_svpbmt;
+    bool ext_svvptc;
     bool ext_zdinx;
     bool ext_zaamo;
     bool ext_zacas;
-- 
2.39.2