The vstart_eq_zero flag is updated at the beginning of the translation
phase from the env->vstart variable. During the execution phase all
functions will set env->vstart = 0 after a successful execution, but the
vstart_eq_zero flag remains the same as at the start of the block. This
will wrongly cause SIGILLs in translations that requires env->vstart = 0
and might be reading vstart_eq_zero = false.
This patch adds a new finalize_rvv_inst() helper that is called at the
end of each vector instruction that will both update vstart_eq_zero and
do a mark_vs_dirty().
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1976
Signed-off-by: Ivan Klokov <ivan.klokov@syntacore.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240314175704.478276-10-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
All helpers that rely on vstart >= vl are now doing early exits using
the VSTART_CHECK_EARLY_EXIT() macro. This macro will not only exit the
helper but also clear vstart.
We're still left with brconds that are skipping the helper, which is the
only place where we're clearing vstart. The pattern goes like this:
tcg_gen_brcond_tl(TCG_COND_GEU, cpu_vstart, cpu_vl, over);
(... calls helper that clears vstart ...)
gen_set_label(over);
return true;
This means that every time we jump to 'over' we're not clearing vstart,
which is an oversight that we're doing across the board.
Instead of setting vstart = 0 manually after each 'over' jump, remove
those brconds that are skipping helpers. The exception will be
trans_vmv_s_x() and trans_vfmv_s_f(): they don't use a helper and are
already clearing vstart manually in the 'over' label.
While we're at it, remove the (vl == 0) brconds from trans_rvbf16.c.inc
too since they're unneeded.
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240314175704.478276-8-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Commit 8ff8ac6329 added a conditional to guard the vext_ldst_whole()
helper if vstart >= evl. But by skipping the helper we're also not
setting vstart = 0 at the end of the insns, which is incorrect.
We'll move the conditional to vext_ldst_whole(), following in line with
the removal of all brconds vstart >= vl that the next patch will do. The
idea is to make the helpers responsible for their own vstart management.
Fix ldst_whole isns by:
- remove the brcond that skips the helper if vstart is >= evl;
- vext_ldst_whole() now does an early exit with the same check, where
evl = (vlenb * nf) >> log2_esz, but the early exit will also clear
vstart.
The 'width' param is now unneeded in ldst_whole_trans() and is also
removed. It was used for the evl calculation for the brcond and has no
other use now. The 'width' is reflected in vext_ldst_whole() via
log2_esz, which is encoded by GEN_VEXT_LD_WHOLE() as
"ctzl(sizeof(ETYPE))".
Suggested-by: Max Chou <max.chou@sifive.com>
Fixes: 8ff8ac6329 ("target/riscv: rvv: Add missing early exit condition for whole register load/store")
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Max Chou <max.chou@sifive.com>
Message-ID: <20240314175704.478276-6-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
These insns have 2 paths: we'll either have vstart already cleared if
vstart_eq_zero or we'll do a brcond to check if vstart >= maxsz to call
the 'vmvr_v' helper. The helper will clear vstart if it executes until
the end, or if vstart >= vl.
For starters, the check itself is wrong: we're checking vstart >= maxsz,
when in fact we should use vstart in bytes, or 'startb' like 'vmvr_v' is
calling, to do the comparison. But even after fixing the comparison we'll
still need to clear vstart in the end, which isn't happening too.
We want to make the helpers responsible to manage vstart, including
these corner cases, precisely to avoid these situations:
- remove the wrong vstart >= maxsz cond from the translation;
- add a 'startb >= maxsz' cond in 'vmvr_v', and clear vstart if that
happens.
This way we're now sure that vstart is being cleared in the end of the
execution, regardless of the path taken.
Fixes: f714361ed7 ("target/riscv: rvv-1.0: implement vstart CSR")
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240314175704.478276-5-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
trans_vmv_x_s, trans_vmv_s_x, trans_vfmv_f_s and trans_vfmv_s_f aren't
setting vstart = 0 after execution. This is usually done by a helper in
vector_helper.c but these functions don't use helpers.
We'll set vstart after any potential 'over' brconds, and that will also
mandate a mark_vs_dirty() too.
Fixes: dedc53cbc9 ("target/riscv: rvv-1.0: integer scalar move instructions")
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240314175704.478276-3-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
While discussing a problem with how we're (not) setting vstart_eq_zero
Richard had the following to say w.r.t the conditional mark_vs_dirty()
calls on load/store functions [1]:
"I think it's required to have stores set dirty unconditionally, before
the operation.
Consider a store that traps on the 2nd element, leaving vstart = 2, and
exiting to the main loop via exception. The exception enters the kernel
page fault handler. The kernel may need to fault in the page for the
process, and in the meantime task switch.
If vs dirty is not already set, the kernel won't know to save vector
state on task switch."
Do a mark_vs_dirty() before both loads and stores.
[1] https://lore.kernel.org/qemu-riscv/72c7503b-0f43-44b8-aa82-fbafed2aac0c@linaro.org/
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240306171932.549549-2-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The Ztso extension is already ratified, this adds it as a CPU property
and adds various fences throughout the port in order to allow TSO
targets to function on weaker hosts. We need no fences for AMOs as
they're already SC, the places we need barriers are described.
These fences are placed in the RISC-V backend rather than TCG as is
planned for x86-on-arm64 because RISC-V allows heterogeneous (and
likely soon dynamic) hart memory models.
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Message-ID: <20240207122256.902627-2-christoph.muellner@vrull.eu>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Calculate the maximum vector size possible, 'max_sz', which is the size
in bytes 'vlenb' multiplied by the max value of LMUL (LMUL = 8, when
s->lmul = 3).
'max_sz' is then shifted right by 'scale', expressed as '3 - s->lmul',
which is clearer than doing 'scale = lmul - 3' and then using '-scale'
in the shift right.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240122161107.26737-10-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The ratified version of RISC-V V spec section 16.6 says that
`The instructions operate as if EEW=SEW`.
So the whole vector register move instructions depend on the vtype
register that means the whole vector register move instructions should
raise an illegal-instruction exception when vtype.vill=1.
Signed-off-by: Max Chou <max.chou@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20231129170400.21251-2-max.chou@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
When icount is not enabled, there is no API in QEMU that can get the
guest instruction number.
Translate the guest code in a way that each TB only has one instruction.
After executing the instruction, decrease the count by 1 until it reaches 0
where the itrigger fires.
Note that only when priviledge matches the itrigger configuration,
the count will decrease.
Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20221013062946.7530-2-zhiwei_liu@linux.alibaba.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
According to v-spec, mask agnostic behavior can be either kept as
undisturbed or set elements' bits to all 1s. To distinguish the
difference of mask policies, QEMU should be able to simulate the mask
agnostic behavior as "set mask elements' bits to all 1s".
There are multiple possibility for agnostic elements according to
v-spec. The main intent of this patch-set tries to add option that
can distinguish between mask policies. Setting agnostic elements to
all 1s allows QEMU to express this.
This is the first commit regarding the optional mask agnostic
behavior. Follow-up commits will add this optional behavior
for all rvv instructions.
Signed-off-by: eop Chen <eop.chen@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <165570784143.17634.35095816584573691-1@git.sr.ht>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
