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Re: [PATCH for-9.0 6/7] target/riscv: add RVA22S64 profile


From: Daniel Henrique Barboza
Subject: Re: [PATCH for-9.0 6/7] target/riscv: add RVA22S64 profile
Date: Fri, 24 Nov 2023 17:13:05 -0300
User-agent: Mozilla Thunderbird



On 11/24/23 14:16, Andrew Jones wrote:
On Thu, Nov 23, 2023 at 04:15:31PM -0300, Daniel Henrique Barboza wrote:
The RVA22S64 profile consists of the following:

- all mandatory extensions of RVA22U64;
- priv spec v1.12.0;
- satp mode sv39;
- Ssccptr, a cache related named feature that we're assuming always
   enable since we don't implement a cache;
- Other named features already implemented: Sstvecd, Sstvala,
   Sscounterenw;
- the new Svade named feature that was recently added.

Most of the work is already done, so this patch is enough to implement
the profile.

After this patch, the 'rva22s64' user flag alone can be used with the
rva64i CPU to boot Linux:

-cpu rv64i,rva22s64=true

This is the /proc/cpuinfo with this profile enabled:

  # cat /proc/cpuinfo
processor       : 0
hart            : 0
isa             : 
rv64imafdc_zicbom_zicbop_zicboz_zicntr_zicsr_zifencei_zihintpause_zihpm_zfhmin_zca_zcd_zba_zbb_zbs_zkt_svinval_svpbmt
mmu             : sv39

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
  target/riscv/cpu.c | 40 ++++++++++++++++++++++++++++++++++++++++
  1 file changed, 40 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index a77118549b..d00548d164 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -1559,8 +1559,48 @@ static RISCVCPUProfile RVA22U64 = {
      }
  };
+/*
+ * As with RVA22U64, RVA22S64 also defines 'named features'.
+ *
+ * Cache related features that we consider enabled since we don't
+ * implement cache: Ssccptr
+ *
+ * Other named features that we already implement: Sstvecd, Sstvala,
+ * Sscounterenw
+ *
+ * Named features that we need to enable: svade
+ *
+ * The remaining features/extensions comes from RVA22U64.
+ */
+static RISCVCPUProfile RVA22S64 = {
+    .name = "rva22s64",
+    .misa_ext = RVI | RVM | RVA | RVF | RVD | RVC | RVU | RVS,
+    .priv_spec = PRIV_VERSION_1_12_0,
+    .satp_mode = VM_1_10_SV39,
+    .ext_offsets = {
+        /* rva22u64 exts and features */
+        CPU_CFG_OFFSET(ext_zicsr), CPU_CFG_OFFSET(ext_zihintpause),
+        CPU_CFG_OFFSET(ext_zba), CPU_CFG_OFFSET(ext_zbb),
+        CPU_CFG_OFFSET(ext_zbs), CPU_CFG_OFFSET(ext_zfhmin),
+        CPU_CFG_OFFSET(ext_zkt), CPU_CFG_OFFSET(ext_zicntr),
+        CPU_CFG_OFFSET(ext_zihpm), CPU_CFG_OFFSET(ext_zicbom),
+        CPU_CFG_OFFSET(ext_zicbop), CPU_CFG_OFFSET(ext_zicboz),
+        CPU_CFG_OFFSET(zic64b),
+
+        /* rva22s64 exts */
+        CPU_CFG_OFFSET(ext_zifencei), CPU_CFG_OFFSET(ext_svpbmt),
+        CPU_CFG_OFFSET(ext_svinval),
+
+        /* rva22s64 named features */
+        CPU_CFG_OFFSET(svade),
+
+        RISCV_PROFILE_EXT_LIST_END
+    }
+};
+
  RISCVCPUProfile *riscv_profiles[] = {
      &RVA22U64,
+    &RVA22S64,
      NULL,
  };
--
2.41.0


Since S-mode profiles will all presumably state they support everything a
U-mode profile supports too, then I wonder if we shouldn't be able to
point S-mode profiles at U-mode profiles somehow, rather than redundantly
add their extensions.

Good point. I just checked and RVA23S64 also works the same way (i.e. the s-mode
mandatory extensions mandates the u-mode mandatory extensions), so this change
is worth doing for the sake of at least these 2 profiles.

I'll add a 'parent' field in the profile description and, if set, a profile
will also enable its parent.


Thanks,


Daniel


Anyway,

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Thanks,
drew



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