* [PATCH v3 2/3] target/riscv: fsd/fsw doesn't dirty FP state
2020-01-15 6:17 [PATCH v3 1/3] target/riscv: Fix tb->flags FS status shihpo.hung
@ 2020-01-15 6:17 ` shihpo.hung
2020-01-15 6:29 ` Alistair Francis
2020-01-15 6:17 ` [PATCH v3 3/3] target/riscv: update mstatus.SD when FS is set dirty shihpo.hung
2020-01-15 6:28 ` [PATCH v3 1/3] target/riscv: Fix tb->flags FS status Alistair Francis
2 siblings, 1 reply; 9+ messages in thread
From: shihpo.hung @ 2020-01-15 6:17 UTC (permalink / raw)
To: qemu-riscv
Cc: Sagar Karandikar, Bastian Koppelmann, Richard Henderson,
qemu-devel, Alistair Francis, Palmer Dabbelt, ShihPo Hung
Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
target/riscv/insn_trans/trans_rvd.inc.c | 1 -
target/riscv/insn_trans/trans_rvf.inc.c | 1 -
2 files changed, 2 deletions(-)
diff --git a/target/riscv/insn_trans/trans_rvd.inc.c b/target/riscv/insn_trans/trans_rvd.inc.c
index 393fa02..ea1044f 100644
--- a/target/riscv/insn_trans/trans_rvd.inc.c
+++ b/target/riscv/insn_trans/trans_rvd.inc.c
@@ -43,7 +43,6 @@ static bool trans_fsd(DisasContext *ctx, arg_fsd *a)
tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEQ);
- mark_fs_dirty(ctx);
tcg_temp_free(t0);
return true;
}
diff --git a/target/riscv/insn_trans/trans_rvf.inc.c b/target/riscv/insn_trans/trans_rvf.inc.c
index 172dbfa..e23cd63 100644
--- a/target/riscv/insn_trans/trans_rvf.inc.c
+++ b/target/riscv/insn_trans/trans_rvf.inc.c
@@ -52,7 +52,6 @@ static bool trans_fsw(DisasContext *ctx, arg_fsw *a)
tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEUL);
tcg_temp_free(t0);
- mark_fs_dirty(ctx);
return true;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v3 2/3] target/riscv: fsd/fsw doesn't dirty FP state
2020-01-15 6:17 ` [PATCH v3 2/3] target/riscv: fsd/fsw doesn't dirty FP state shihpo.hung
@ 2020-01-15 6:29 ` Alistair Francis
0 siblings, 0 replies; 9+ messages in thread
From: Alistair Francis @ 2020-01-15 6:29 UTC (permalink / raw)
To: shihpo.hung
Cc: open list:RISC-V, Sagar Karandikar, Bastian Koppelmann,
Richard Henderson, qemu-devel@nongnu.org Developers,
Alistair Francis, Palmer Dabbelt
On Wed, Jan 15, 2020 at 4:18 PM <shihpo.hung@sifive.com> wrote:
>
> Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Alistair
> ---
> target/riscv/insn_trans/trans_rvd.inc.c | 1 -
> target/riscv/insn_trans/trans_rvf.inc.c | 1 -
> 2 files changed, 2 deletions(-)
>
> diff --git a/target/riscv/insn_trans/trans_rvd.inc.c b/target/riscv/insn_trans/trans_rvd.inc.c
> index 393fa02..ea1044f 100644
> --- a/target/riscv/insn_trans/trans_rvd.inc.c
> +++ b/target/riscv/insn_trans/trans_rvd.inc.c
> @@ -43,7 +43,6 @@ static bool trans_fsd(DisasContext *ctx, arg_fsd *a)
>
> tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEQ);
>
> - mark_fs_dirty(ctx);
> tcg_temp_free(t0);
> return true;
> }
> diff --git a/target/riscv/insn_trans/trans_rvf.inc.c b/target/riscv/insn_trans/trans_rvf.inc.c
> index 172dbfa..e23cd63 100644
> --- a/target/riscv/insn_trans/trans_rvf.inc.c
> +++ b/target/riscv/insn_trans/trans_rvf.inc.c
> @@ -52,7 +52,6 @@ static bool trans_fsw(DisasContext *ctx, arg_fsw *a)
> tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEUL);
>
> tcg_temp_free(t0);
> - mark_fs_dirty(ctx);
> return true;
> }
>
> --
> 2.7.4
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v3 3/3] target/riscv: update mstatus.SD when FS is set dirty
2020-01-15 6:17 [PATCH v3 1/3] target/riscv: Fix tb->flags FS status shihpo.hung
2020-01-15 6:17 ` [PATCH v3 2/3] target/riscv: fsd/fsw doesn't dirty FP state shihpo.hung
@ 2020-01-15 6:17 ` shihpo.hung
2020-01-15 6:30 ` Alistair Francis
2020-01-15 6:28 ` [PATCH v3 1/3] target/riscv: Fix tb->flags FS status Alistair Francis
2 siblings, 1 reply; 9+ messages in thread
From: shihpo.hung @ 2020-01-15 6:17 UTC (permalink / raw)
To: qemu-riscv
Cc: Sagar Karandikar, Bastian Koppelmann, Richard Henderson,
qemu-devel, Alistair Francis, Palmer Dabbelt, ShihPo Hung
remove the check becuase SD bit should summarize FS and XS fields
unconditionally.
Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
target/riscv/csr.c | 3 +--
target/riscv/translate.c | 2 +-
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index da02f9f..0e34c29 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -341,8 +341,7 @@ static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
mstatus = (mstatus & ~mask) | (val & mask);
- dirty = (riscv_cpu_fp_enabled(env) &&
- ((mstatus & MSTATUS_FS) == MSTATUS_FS)) |
+ dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
((mstatus & MSTATUS_XS) == MSTATUS_XS);
mstatus = set_field(mstatus, MSTATUS_SD, dirty);
env->mstatus = mstatus;
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index ab6a891..8e40ed3 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -394,7 +394,7 @@ static void mark_fs_dirty(DisasContext *ctx)
tmp = tcg_temp_new();
tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
- tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
+ tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | MSTATUS_SD);
tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
tcg_temp_free(tmp);
}
--
2.7.4
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v3 3/3] target/riscv: update mstatus.SD when FS is set dirty
2020-01-15 6:17 ` [PATCH v3 3/3] target/riscv: update mstatus.SD when FS is set dirty shihpo.hung
@ 2020-01-15 6:30 ` Alistair Francis
0 siblings, 0 replies; 9+ messages in thread
From: Alistair Francis @ 2020-01-15 6:30 UTC (permalink / raw)
To: shihpo.hung
Cc: open list:RISC-V, Sagar Karandikar, Bastian Koppelmann,
Richard Henderson, qemu-devel@nongnu.org Developers,
Alistair Francis, Palmer Dabbelt
On Wed, Jan 15, 2020 at 4:19 PM <shihpo.hung@sifive.com> wrote:
>
> remove the check becuase SD bit should summarize FS and XS fields
> unconditionally.
>
> Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Alistair
> ---
> target/riscv/csr.c | 3 +--
> target/riscv/translate.c | 2 +-
> 2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index da02f9f..0e34c29 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -341,8 +341,7 @@ static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
>
> mstatus = (mstatus & ~mask) | (val & mask);
>
> - dirty = (riscv_cpu_fp_enabled(env) &&
> - ((mstatus & MSTATUS_FS) == MSTATUS_FS)) |
> + dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
> ((mstatus & MSTATUS_XS) == MSTATUS_XS);
> mstatus = set_field(mstatus, MSTATUS_SD, dirty);
> env->mstatus = mstatus;
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index ab6a891..8e40ed3 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -394,7 +394,7 @@ static void mark_fs_dirty(DisasContext *ctx)
>
> tmp = tcg_temp_new();
> tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
> - tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
> + tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | MSTATUS_SD);
> tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
> tcg_temp_free(tmp);
> }
> --
> 2.7.4
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 1/3] target/riscv: Fix tb->flags FS status
2020-01-15 6:17 [PATCH v3 1/3] target/riscv: Fix tb->flags FS status shihpo.hung
2020-01-15 6:17 ` [PATCH v3 2/3] target/riscv: fsd/fsw doesn't dirty FP state shihpo.hung
2020-01-15 6:17 ` [PATCH v3 3/3] target/riscv: update mstatus.SD when FS is set dirty shihpo.hung
@ 2020-01-15 6:28 ` Alistair Francis
2020-01-15 14:27 ` ShihPo Hung
2020-01-15 21:46 ` Richard Henderson
2 siblings, 2 replies; 9+ messages in thread
From: Alistair Francis @ 2020-01-15 6:28 UTC (permalink / raw)
To: shihpo.hung
Cc: open list:RISC-V, Sagar Karandikar, Bastian Koppelmann,
Richard Henderson, qemu-devel@nongnu.org Developers,
Alistair Francis, Palmer Dabbelt
On Wed, Jan 15, 2020 at 4:18 PM <shihpo.hung@sifive.com> wrote:
>
> It was found that running libquantum on riscv-linux qemu produced an
> incorrect result. After investigation, FP registers are not saved
> during context switch due to incorrect mstatus.FS.
>
> In current implementation tb->flags merges all non-disabled state to
> dirty. This means the code in mark_fs_dirty in translate.c that
> handles initial and clean states is unreachable.
>
> This patch fixes it and is successfully tested with:
> libquantum
>
> Thanks to Richard for pointing out the actual bug.
>
> v3: remove the redundant condition
> v2: root cause FS problem
>
> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> target/riscv/cpu.h | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index e59343e..de0a8d8 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -293,10 +293,7 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
> #ifdef CONFIG_USER_ONLY
> *flags = TB_FLAGS_MSTATUS_FS;
> #else
> - *flags = cpu_mmu_index(env, 0);
> - if (riscv_cpu_fp_enabled(env)) {
> - *flags |= TB_FLAGS_MSTATUS_FS;
> - }
> + *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
I don't think this is right, you should use the riscv_cpu_fp_enabled() function.
Right now it's the same as env->mstatus & MSTATUS_FS but when the
Hypervisor extension goes in riscv_cpu_fp_enabled() will be more
complex.
Alistair
> #endif
> }
>
> --
> 2.7.4
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH v3 1/3] target/riscv: Fix tb->flags FS status
2020-01-15 6:28 ` [PATCH v3 1/3] target/riscv: Fix tb->flags FS status Alistair Francis
@ 2020-01-15 14:27 ` ShihPo Hung
2020-01-15 21:46 ` Richard Henderson
1 sibling, 0 replies; 9+ messages in thread
From: ShihPo Hung @ 2020-01-15 14:27 UTC (permalink / raw)
To: Alistair Francis
Cc: open list:RISC-V, Sagar Karandikar, Bastian Koppelmann,
Richard Henderson, qemu-devel@nongnu.org Developers,
Alistair Francis, Palmer Dabbelt
[-- Attachment #1: Type: text/plain, Size: 974 bytes --]
On Wed, Jan 15, 2020 at 2:29 PM Alistair Francis <alistair23@gmail.com>
wrote:
> > - *flags = cpu_mmu_index(env, 0);
> > - if (riscv_cpu_fp_enabled(env)) {
> > - *flags |= TB_FLAGS_MSTATUS_FS;
> > - }
> > + *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
>
> I don't think this is right, you should use the riscv_cpu_fp_enabled()
> function.
>
> Right now it's the same as env->mstatus & MSTATUS_FS but when the
> Hypervisor extension goes in riscv_cpu_fp_enabled() will be more
> complex.
>
> Alistair
>
> I agree using riscv_cpu_fp_enabled() to hide the complexity when checking
FP,
but here I only duplicate the FP status (disabled/initial/clean/dirty) to
tb->flags
no matter FP is enabled or not.
Is it still necessary to check this before duplicating it?
I think it is not as long as TB_FLAGS_MSTATUS_FS is equivalent to
MSTATUS_FS.
But I don't know what changes hypervisor extension brings, please correct
me if I am wrong.
ShihPo
[-- Attachment #2: Type: text/html, Size: 1504 bytes --]
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH v3 1/3] target/riscv: Fix tb->flags FS status
2020-01-15 6:28 ` [PATCH v3 1/3] target/riscv: Fix tb->flags FS status Alistair Francis
2020-01-15 14:27 ` ShihPo Hung
@ 2020-01-15 21:46 ` Richard Henderson
2020-01-15 23:06 ` Alistair Francis
1 sibling, 1 reply; 9+ messages in thread
From: Richard Henderson @ 2020-01-15 21:46 UTC (permalink / raw)
To: Alistair Francis, shihpo.hung
Cc: open list:RISC-V, Sagar Karandikar, Bastian Koppelmann,
qemu-devel@nongnu.org Developers, Alistair Francis,
Palmer Dabbelt
On 1/14/20 8:28 PM, Alistair Francis wrote:
> On Wed, Jan 15, 2020 at 4:18 PM <shihpo.hung@sifive.com> wrote:
>>
>> It was found that running libquantum on riscv-linux qemu produced an
>> incorrect result. After investigation, FP registers are not saved
>> during context switch due to incorrect mstatus.FS.
>>
>> In current implementation tb->flags merges all non-disabled state to
>> dirty. This means the code in mark_fs_dirty in translate.c that
>> handles initial and clean states is unreachable.
>>
>> This patch fixes it and is successfully tested with:
>> libquantum
>>
>> Thanks to Richard for pointing out the actual bug.
>>
>> v3: remove the redundant condition
>> v2: root cause FS problem
>>
>> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
>> Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>> target/riscv/cpu.h | 5 +----
>> 1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
>> index e59343e..de0a8d8 100644
>> --- a/target/riscv/cpu.h
>> +++ b/target/riscv/cpu.h
>> @@ -293,10 +293,7 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
>> #ifdef CONFIG_USER_ONLY
>> *flags = TB_FLAGS_MSTATUS_FS;
>> #else
>> - *flags = cpu_mmu_index(env, 0);
>> - if (riscv_cpu_fp_enabled(env)) {
>> - *flags |= TB_FLAGS_MSTATUS_FS;
>> - }
>> + *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
>
> I don't think this is right, you should use the riscv_cpu_fp_enabled() function.
>
> Right now it's the same as env->mstatus & MSTATUS_FS but when the
> Hypervisor extension goes in riscv_cpu_fp_enabled() will be more
> complex.
Hmm. Are you sure something like
flags |= riscv_cpu_effective_mstatus(env) & MSTATUS_FS;
wouldn't be more appropriate for the hypervisor extension?
I guess I should have another browse through your hv patchset, but I worry now
about bare uses of env->mstatus, if they no longer mean what they appear to mean.
r~
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH v3 1/3] target/riscv: Fix tb->flags FS status
2020-01-15 21:46 ` Richard Henderson
@ 2020-01-15 23:06 ` Alistair Francis
0 siblings, 0 replies; 9+ messages in thread
From: Alistair Francis @ 2020-01-15 23:06 UTC (permalink / raw)
To: Richard Henderson
Cc: open list:RISC-V, Sagar Karandikar, Bastian Koppelmann,
qemu-devel@nongnu.org Developers, Alistair Francis,
Palmer Dabbelt, shihpo.hung
On Thu, Jan 16, 2020 at 7:46 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 1/14/20 8:28 PM, Alistair Francis wrote:
> > On Wed, Jan 15, 2020 at 4:18 PM <shihpo.hung@sifive.com> wrote:
> >>
> >> It was found that running libquantum on riscv-linux qemu produced an
> >> incorrect result. After investigation, FP registers are not saved
> >> during context switch due to incorrect mstatus.FS.
> >>
> >> In current implementation tb->flags merges all non-disabled state to
> >> dirty. This means the code in mark_fs_dirty in translate.c that
> >> handles initial and clean states is unreachable.
> >>
> >> This patch fixes it and is successfully tested with:
> >> libquantum
> >>
> >> Thanks to Richard for pointing out the actual bug.
> >>
> >> v3: remove the redundant condition
> >> v2: root cause FS problem
> >>
> >> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
> >> Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
> >> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> >> ---
> >> target/riscv/cpu.h | 5 +----
> >> 1 file changed, 1 insertion(+), 4 deletions(-)
> >>
> >> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> >> index e59343e..de0a8d8 100644
> >> --- a/target/riscv/cpu.h
> >> +++ b/target/riscv/cpu.h
> >> @@ -293,10 +293,7 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
> >> #ifdef CONFIG_USER_ONLY
> >> *flags = TB_FLAGS_MSTATUS_FS;
> >> #else
> >> - *flags = cpu_mmu_index(env, 0);
> >> - if (riscv_cpu_fp_enabled(env)) {
> >> - *flags |= TB_FLAGS_MSTATUS_FS;
> >> - }
> >> + *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
> >
> > I don't think this is right, you should use the riscv_cpu_fp_enabled() function.
> >
> > Right now it's the same as env->mstatus & MSTATUS_FS but when the
> > Hypervisor extension goes in riscv_cpu_fp_enabled() will be more
> > complex.
>
> Hmm. Are you sure something like
>
> flags |= riscv_cpu_effective_mstatus(env) & MSTATUS_FS;
>
> wouldn't be more appropriate for the hypervisor extension?
I was more thinking:
if (riscv_cpu_fp_enabled(env)) {
*flags |= env->mstatus & MSTATUS_FS;
}
as floating point can be disabled from multiple places when we have
the H extension.
>
> I guess I should have another browse through your hv patchset, but I worry now
> about bare uses of env->mstatus, if they no longer mean what they appear to mean.
That was why this was all refacted in the first place as we now need
to check against env->vsstatus as well (depending on virt status).
Alistair
>
>
> r~
^ permalink raw reply [flat|nested] 9+ messages in thread