Hi,
Thanks for the patch, and apologies for not reviewing earlier
versions.
On Fri, May 07, 2021 at 04:00:58PM +0800, Ziqiao Kong wrote:
> Changes since v3:
> - Split the long patches to series to make review easier.
> - Fix the coding style problems in v3.
>
> Changes since v2:
> - Change the sequence of fpcs, fpds, fpip and fpdp in CPUX86State.
> - Use stl instead of stw in do_fstenv.
> - Move variables to floats instruction case block.
> - Move last accessed memory operand to a temp variable to avoid another load.
> - Move segment selectors instead of segment base to fpcs and fpds.
> - Fix some code stype problems for the original code in floats case block.
On the next versions, please include the changelog after a "---"
line, so it won't be included in the final commit.
In addition to the changelog, the actual commit message (the text
above "---") needs to include an explanation for the change. If
you are fixing a bug, please explain what's the bug you are
fixing.
>
> Signed-off-by: Ziqiao Kong <ziqiaok...@gmail.com>
> ---
> target/i386/cpu.h | 4 +++
> target/i386/tcg/fpu_helper.c | 48 ++++++++++++++++++++++--------------
> target/i386/tcg/translate.c | 45 ++++++++++++++++++++++++++++++++-
> 3 files changed, 77 insertions(+), 20 deletions(-)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 570f916878..241945320b 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -705,6 +705,8 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS];
> #define CPUID_7_0_EBX_INVPCID (1U << 10)
> /* Restricted Transactional Memory */
> #define CPUID_7_0_EBX_RTM (1U << 11)
> +/* Deprecates FPU CS and FPU DS values */
> +#define CPUID_7_0_EBX_FCS_FDS (1U << 13)
> /* Memory Protection Extension */
> #define CPUID_7_0_EBX_MPX (1U << 14)
> /* AVX-512 Foundation */
> @@ -1440,6 +1442,8 @@ typedef struct CPUX86State {
> FPReg fpregs[8];
> /* KVM-only so far */
> uint16_t fpop;
> + uint16_t fpcs;
> + uint16_t fpds;
> uint64_t fpip;
> uint64_t fpdp;
>
> diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c
> index 60ed93520a..f1a8717ed8 100644
> --- a/target/i386/tcg/fpu_helper.c
> +++ b/target/i386/tcg/fpu_helper.c
> @@ -766,6 +766,10 @@ void helper_fninit(CPUX86State *env)
> {
> env->fpus = 0;
> env->fpstt = 0;
> + env->fpcs = 0;
> + env->fpip = 0;
> + env->fpds = 0;
> + env->fpdp = 0;
> cpu_set_fpuc(env, 0x37f);
> env->fptags[0] = 1;
> env->fptags[1] = 1;
> @@ -2368,6 +2372,7 @@ static void do_fstenv(CPUX86State *env, target_ulong
> ptr, int data32,
> {
> int fpus, fptag, exp, i;
> uint64_t mant;
> + uint16_t fpcs, fpds;
> CPU_LDoubleU tmp;
>
> fpus = (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11;
> @@ -2390,24 +2395,39 @@ static void do_fstenv(CPUX86State *env, target_ulong
> ptr, int data32,
> }
> }
> }
> +
> + /*
> + * If CR0.PE = 1, each instruction saves FCS and FDS into memory. If
> + * CPUID.(EAX=07H,ECX=0H):EBX[bit 13] = 1, the processor deprecates
> + * FCS and FDS; it saves each as 0000H.
> + */
> + if (!(env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_FCS_FDS)
> + && (env->cr[0] & CR0_PE_MASK)) {
> + fpcs = env->fpcs;
> + fpds = env->fpds;
If you want to start supporting this feature flag, I suggest
moving this to a separate patch. The description of this patch
seems to imply it is just a bug fix, not the implementation of a
new feature flag.
When adding support for a new feature flag in TCG code, you need
to extend TCG_*_FEATURES in target/i386/cpu.c, otherwise the
feature flag will never be enabled by the CPU configuration code.
> + } else {
> + fpcs = 0;
> + fpds = 0;
> + }
> +
> if (data32) {
> /* 32 bit */
> cpu_stl_data_ra(env, ptr, env->fpuc, retaddr);
> cpu_stl_data_ra(env, ptr + 4, fpus, retaddr);
> cpu_stl_data_ra(env, ptr + 8, fptag, retaddr);
> - cpu_stl_data_ra(env, ptr + 12, 0, retaddr); /* fpip */
> - cpu_stl_data_ra(env, ptr + 16, 0, retaddr); /* fpcs */
> - cpu_stl_data_ra(env, ptr + 20, 0, retaddr); /* fpoo */
> - cpu_stl_data_ra(env, ptr + 24, 0, retaddr); /* fpos */
> + cpu_stl_data_ra(env, ptr + 12, env->fpip, retaddr); /* fpip */
> + cpu_stl_data_ra(env, ptr + 16, fpcs, retaddr); /* fpcs */
> + cpu_stl_data_ra(env, ptr + 20, env->fpdp, retaddr); /* fpdp */
> + cpu_stl_data_ra(env, ptr + 24, fpds, retaddr); /* fpds */
> } else {
> /* 16 bit */
> cpu_stw_data_ra(env, ptr, env->fpuc, retaddr);
> cpu_stw_data_ra(env, ptr + 2, fpus, retaddr);
> cpu_stw_data_ra(env, ptr + 4, fptag, retaddr);
> - cpu_stw_data_ra(env, ptr + 6, 0, retaddr);
> - cpu_stw_data_ra(env, ptr + 8, 0, retaddr);
> - cpu_stw_data_ra(env, ptr + 10, 0, retaddr);
> - cpu_stw_data_ra(env, ptr + 12, 0, retaddr);
> + cpu_stw_data_ra(env, ptr + 6, env->fpip, retaddr);
> + cpu_stw_data_ra(env, ptr + 8, fpcs, retaddr);
> + cpu_stw_data_ra(env, ptr + 10, env->fpdp, retaddr);
> + cpu_stw_data_ra(env, ptr + 12, fpds, retaddr);
> }
> }
>
> @@ -2473,17 +2493,7 @@ void helper_fsave(CPUX86State *env, target_ulong ptr,
> int data32)
> }
>
> /* fninit */
> - env->fpus = 0;
> - env->fpstt = 0;
> - cpu_set_fpuc(env, 0x37f);
> - env->fptags[0] = 1;
> - env->fptags[1] = 1;
> - env->fptags[2] = 1;
> - env->fptags[3] = 1;
> - env->fptags[4] = 1;
> - env->fptags[5] = 1;
> - env->fptags[6] = 1;
> - env->fptags[7] = 1;
> + helper_fninit(env);
> }
>
> void helper_frstor(CPUX86State *env, target_ulong ptr, int data32)
> diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> index 52e94fe106..59647ea5b7 100644
> --- a/target/i386/tcg/translate.c
> +++ b/target/i386/tcg/translate.c
> @@ -5839,6 +5839,11 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> /* floats */
> case 0xd8 ... 0xdf:
> {
> + TCGv last_addr = tcg_temp_new();
> + int last_seg;
> + bool update_fdp = false;
> + bool update_fip = true;
> +
> if (s->flags & (HF_EM_MASK | HF_TS_MASK)) {
> /* if CR0.EM or CR0.TS are set, generate an FPU exception */
> /* XXX: what to do if illegal op ? */
> @@ -5851,7 +5856,14 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> op = ((b & 7) << 3) | ((modrm >> 3) & 7);
> if (mod != 3) {
> /* memory op */
> - gen_lea_modrm(env, s, modrm);
> + AddressParts a = gen_lea_modrm_0(env, s, modrm);
> + TCGv ea = gen_lea_modrm_1(s, a);
> +
> + update_fdp = true;
> + last_seg = a.def_seg;
> + tcg_gen_mov_tl(last_addr, ea);
> + gen_lea_v_seg(s, s->aflag, ea, a.def_seg, s->override);
> +
> switch (op) {
> case 0x00 ... 0x07: /* fxxxs */
> case 0x10 ... 0x17: /* fixxxl */
> @@ -5978,19 +5990,23 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> break;
> case 0x0c: /* fldenv mem */
> gen_helper_fldenv(cpu_env, s->A0, tcg_const_i32(dflag -
> 1));
> + update_fip = update_fdp = false;
> break;
> case 0x0d: /* fldcw mem */
> tcg_gen_qemu_ld_i32(s->tmp2_i32, s->A0,
> s->mem_index, MO_LEUW);
> gen_helper_fldcw(cpu_env, s->tmp2_i32);
> + update_fip = update_fdp = false;
> break;
> case 0x0e: /* fnstenv mem */
> gen_helper_fstenv(cpu_env, s->A0, tcg_const_i32(dflag -
> 1));
> + update_fip = update_fdp = false;
> break;
> case 0x0f: /* fnstcw mem */
> gen_helper_fnstcw(s->tmp2_i32, cpu_env);
> tcg_gen_qemu_st_i32(s->tmp2_i32, s->A0,
> s->mem_index, MO_LEUW);
> + update_fip = update_fdp = false;
> break;
> case 0x1d: /* fldt mem */
> gen_helper_fldt_ST0(cpu_env, s->A0);
> @@ -6001,14 +6017,17 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> break;
> case 0x2c: /* frstor mem */
> gen_helper_frstor(cpu_env, s->A0, tcg_const_i32(dflag -
> 1));
> + update_fip = update_fdp = false;
> break;
> case 0x2e: /* fnsave mem */
> gen_helper_fsave(cpu_env, s->A0, tcg_const_i32(dflag -
> 1));
> + update_fip = update_fdp = false;
> break;
> case 0x2f: /* fnstsw mem */
> gen_helper_fnstsw(s->tmp2_i32, cpu_env);
> tcg_gen_qemu_st_i32(s->tmp2_i32, s->A0,
> s->mem_index, MO_LEUW);
> + update_fip = update_fdp = false;
> break;
> case 0x3c: /* fbld */
> gen_helper_fbld_ST0(cpu_env, s->A0);
> @@ -6051,6 +6070,7 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> case 0: /* fnop */
> /* check exceptions (FreeBSD FPU probe) */
> gen_helper_fwait(cpu_env);
> + update_fip = update_fdp = false;
> break;
> default:
> goto unknown_op;
> @@ -6220,9 +6240,11 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> break;
> case 2: /* fclex */
> gen_helper_fclex(cpu_env);
> + update_fip = update_fdp = false;
> break;
> case 3: /* fninit */
> gen_helper_fninit(cpu_env);
> + update_fip = update_fdp = false;
> break;
> case 4: /* fsetpm (287 only, just do nop here) */
> break;
> @@ -6343,6 +6365,27 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> goto unknown_op;
> }
> }
> +
> + if (update_fip) {
> + tcg_gen_ld32u_tl(s->T0, cpu_env,
> + offsetof(CPUX86State, segs[R_CS].selector));
> + tcg_gen_st16_tl(s->T0, cpu_env, offsetof(CPUX86State, fpcs));
> +
> + tcg_gen_movi_tl(s->T0, pc_start - s->cs_base);
> + tcg_gen_st_tl(s->T0, cpu_env, offsetof(CPUX86State, fpip));
> + }
> +
> + if (update_fdp) {
> + if (s->override >= 0) {
> + last_seg = s->override;
> + }
> + tcg_gen_ld32u_tl(s->T0, cpu_env,
> + offsetof(CPUX86State,
> + segs[last_seg].selector));
> + tcg_gen_st16_tl(s->T0, cpu_env, offsetof(CPUX86State, fpds));
> +
> + tcg_gen_st_tl(last_addr, cpu_env, offsetof(CPUX86State,
> fpdp));
> + }
> }
> break;
> /************************/
> --
> 2.25.1
>
--
Eduardo
