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From: | Weiwei Li |
Subject: | Re: [PATCH v6 1/5] target/riscv: Ignore reserved bits in PTE for RV64 |
Date: | Tue, 25 Jan 2022 17:44:37 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 |
在 2022/1/25 下午5:00, Guo Ren 写道:
On Tue, Jan 25, 2022 at 4:54 PM LIU Zhiwei <zhiwei_liu@c-sky.com> wrote:On 2022/1/25 16:40, Guo Ren wrote:On Tue, Jan 25, 2022 at 4:34 PM LIU Zhiwei <zhiwei_liu@c-sky.com> wrote:On 2022/1/25 14:45, Weiwei Li wrote:From: Guo Ren <ren_guo@c-sky.com> Highest bits of PTE has been used for svpbmt, ref: [1], [2], so we need to ignore them. They cannot be a part of ppn. 1: The RISC-V Instruction Set Manual, Volume II: Privileged Architecture 4.4 Sv39: Page-Based 39-bit Virtual-Memory System 4.5 Sv48: Page-Based 48-bit Virtual-Memory System 2: https://github.com/riscv/virtual-memory/blob/main/specs/663-Svpbmt-diff.pdf Signed-off-by: Guo Ren <ren_guo@c-sky.com> Cc: Liu Zhiwei <zhiwei_liu@c-sky.com> Cc: Bin Meng <bmeng.cn@gmail.com> Cc: Alistair Francis <alistair.francis@wdc.com> --- target/riscv/cpu.h | 13 +++++++++++++ target/riscv/cpu_bits.h | 7 +++++++ target/riscv/cpu_helper.c | 14 +++++++++++++- 3 files changed, 33 insertions(+), 1 deletion(-) diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 55635d68d5..45de8faaca 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -341,6 +341,8 @@ struct RISCVCPU { bool ext_counters; bool ext_ifencei; bool ext_icsr; + bool ext_svnapot; + bool ext_svpbmt; bool ext_zfh; bool ext_zfhmin; bool ext_zve32f; @@ -495,6 +497,17 @@ static inline int riscv_cpu_xlen(CPURISCVState *env) return 16 << env->xl; } +#ifndef CONFIG_USER_ONLY +#ifdef TARGET_RISCV32 +#define riscv_cpu_sxl(env) ((void)(env), MXL_RV32) +#else +static inline RISCVMXL riscv_cpu_sxl(CPURISCVState *env) +{ + return get_field(env->mstatus, MSTATUS64_SXL); +} +#endif +#endif +Perhaps an interface also works for user mode is better. +#ifdef TARGET_RISCV32 +#define riscv_cpu_sxl(env) ((void)(env), MXL_RV32) +#else +static inline RISCVMXL riscv_cpu_sxl(CPURISCVState *env) +{ +#ifdef CONFIG_USER_ONLY + return env->misa_mxl; +#else + return get_field(env->mstatus, MSTATUS64_SXL); +#endif +} +#endif +/* * Encode LMUL to lmul as follows: * LMUL vlmul lmul diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h index 7c87433645..37b622fbfa 100644 --- a/target/riscv/cpu_bits.h +++ b/target/riscv/cpu_bits.h @@ -493,6 +493,13 @@ typedef enum { /* Page table PPN shift amount */ #define PTE_PPN_SHIFT 10 +/* Page table PPN mask */ +#if defined(TARGET_RISCV32) +#define PTE_PPN_MASK 0xFFFFFC00UL +#elif defined(TARGET_RISCV64) +#define PTE_PPN_MASK 0x3FFFFFFFFFFC00ULL +#endif +No need to define PTE_PPN_MASK for TARGET_RISCV32.ppn = (pte & PTE_PPN_MASK) >> PTE_PPN_SHIFT; pte is target_ulong, so types are different. TARGET_RISCV32: is 32bit. TARGET_RISCV64: is 64bit.I should make it more clear. You will not use PTE_PPN_MASK on TARGET_RISCV32./* Leaf page shift amount */ #define PGSHIFT 12 diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 327a2c4f1d..2a921bedfd 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -622,7 +622,19 @@ restart: return TRANSLATE_FAIL; } - hwaddr ppn = pte >> PTE_PPN_SHIFT; + hwaddr ppn; + RISCVCPU *cpu = env_archcpu(env); + + if (riscv_cpu_sxl(env) == MXL_RV32) { + ppn = pte >> PTE_PPN_SHIFT;TARGET_RISCV32 will always come here. So no need to define PTE_PPN_MASK for TARGET_RISCV32.Oops, maybe we should use TARGET_LONG_SIZE == 4 #if TARGET_LONG_SIZE == 4 typedef int32_t target_long; typedef uint32_t target_ulong; #define TARGET_FMT_lx "%08x" #define TARGET_FMT_ld "%d" #define TARGET_FMT_lu "%u" #elif TARGET_LONG_SIZE == 8 typedef int64_t target_long; typedef uint64_t target_ulong; #define TARGET_FMT_lx "%016" PRIx64 #define TARGET_FMT_ld "%" PRId64 #define TARGET_FMT_lu "%" PRIu64 #else #error TARGET_LONG_SIZE undefined #endif
TARGET_LONG_SIZE is related to TARGET_RISCV32 and TARGET_RISCV64. In RV32, the code will truely not reach there when executing. However the code itself have different types for pte and PTE_PPN_MASK, and may cause compiler warning. So if we only define PTE_PPN_MASK for RV64, maybe we can take type casting here: ppn = (pte & (target_ulong)PTE_PPN_MASK) >> PTE_PPN_SHIFT; Regards, Weiwei Li
Thanks, Zhiwei+ } else if (cpu->cfg.ext_svpbmt || cpu->cfg.ext_svnapot) { + ppn = (pte & PTE_PPN_MASK) >> PTE_PPN_SHIFT; + } else { + ppn = pte >> PTE_PPN_SHIFT; + if ((pte & ~PTE_PPN_MASK) >> PTE_PPN_SHIFT) { + return TRANSLATE_FAIL; + } + } if (!(pte & PTE_V)) { /* Invalid PTE */Otherwise, Reviewed-by: LIU Zhiwei <zhiwei_liu@c-sky.com> Thanks, Zhiwei
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