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 commit adds option 'rvv_ma_all_1s' is added to enable the
behavior, it is default as disabled.
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: <165570784143.17634.35095816584573691-10@git.sr.ht>
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>
Just add 1 to the effective privledge level when in HS mode, then reuse
the check of 'effective_priv < csr_priv' in riscv_csrrw_check to replace
the privilege level related check in hmode. Then, hmode will only check
whether H extension is supported.
When accessing Hypervior CSRs:
1) If accessing from M privilege level, the check of
'effective_priv< csr_priv' passes, returns hmode(...) which will return
RISCV_EXCP_ILLEGAL_INST when H extension is not supported and return
RISCV_EXCP_NONE otherwise.
2) If accessing from HS privilege level, effective_priv will add 1,
the check passes and also returns hmode(...) too.
3) If accessing from VS/VU privilege level, the check fails, and
returns RISCV_EXCP_VIRT_INSTRUCTION_FAULT
4) If accessing from U privilege level, the check fails, and returns
RISCV_EXCP_ILLEGAL_INST
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-Id: <20220718130955.11899-7-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Add check for the implicit dependence between H and S
Csrs only existed in RV32 will not trigger virtual instruction fault
when not in RV32 based on section 8.6.1 of riscv-privileged spec
(draft-20220717)
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220718130955.11899-6-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Add umode/umode32 predicate for mcounteren, menvcfg/menvcfgh
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-Id: <20220718130955.11899-5-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Fix the lines with over 80 characters
Fix the lines which are obviously misalgined with other lines in the
same group
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-Id: <20220718130955.11899-4-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Add check for "H depends on an I base integer ISA with 32 x registers"
which is stated at the beginning of chapter 8 of the riscv-privileged
spec(draft-20220717)
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-Id: <20220718130955.11899-3-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
There are 3 suggested privilege mode combinations listed in section 1.2
of the riscv-privileged spec(draft-20220717):
1) M, 2) M, U 3) M, S, U
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-Id: <20220718130955.11899-2-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
- Zmmul is ratified and is now version 1.0
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220710101546.3907-1-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
For rv128c shifts, a shamt of 0 is a shamt of 64, while for rv32c/rv64c
it stays 0 and is a hint instruction that does not change processor state.
For rv128c right shifts, the 6-bit shamt is in addition sign extended to
7 bits.
Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220710110451.245567-1-frederic.petrot@univ-grenoble-alpes.fr>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
We should disable extensions in riscv_cpu_realize() if minimum required
priv spec version is not satisfied. This also ensures that machines with
priv spec v1.11 (or lower) cannot enable H, V, and various multi-letter
extensions.
Fixes: a775398be2 ("target/riscv: Add isa extenstion strings to the device tree")
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Rahul Pathak <rpathak@ventanamicro.com>
Message-Id: <20220630061150.905174-3-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
We should write transformed instruction encoding of the trapped
instruction in [m|h]tinst CSR at time of taking trap as defined
by the RISC-V privileged specification v1.12.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Acked-by: dramforever <dramforever@live.com>
Message-Id: <20220630061150.905174-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Right now the translator stops right *after* the end of a page, which
breaks reporting of fault locations when the last instruction of a
multi-insn translation block crosses a page boundary.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1155
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
These will be useful in properly ending the TB.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Pass these along to translator_loop -- pc may be used instead
of tb->pc, and host_pc is currently unused. Adjust all targets
at one time.
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We got to talking about how Zmmul and M interact with each other
https://github.com/riscv/riscv-isa-manual/issues/869 , and it turns out
that QEMU's behavior is slightly wrong: having Zmmul and M is a legal
combination, it just means that the multiplication instructions are
supported even when M is disabled at runtime via misa.
This just stops overriding M from Zmmul, with that the other checks for
the multiplication instructions work as per the ISA.
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220714180033.22385-1-palmer@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The latest AIA draft v0.3.0 defines a relatively simpler scheme for
default priority assignments where:
1) local interrupts 24 to 31 and 48 to 63 are reserved for custom use
and have implementation specific default priority.
2) remaining local interrupts 0 to 23 and 32 to 47 have a recommended
(not mandatory) priority assignments.
We update the default priority table and hviprio mapping as-per above.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220616031543.953776-3-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Based on architecture review committee feedback, the [m|s|vs]seteienum,
[m|s|vs]clreienum, [m|s|vs]seteipnum, and [m|s|vs]clreipnum CSRs are
removed in the latest AIA draft v0.3.0 specification.
(Refer, https://github.com/riscv/riscv-aia/releases/tag/0.3.0-draft.31)
These CSRs were mostly for software convenience and software can always
use [m|s|vs]iselect and [m|s|vs]ireg CSRs to update the IMSIC interrupt
file bits.
We update the IMSIC CSR emulation as-per above to match the latest AIA
draft specification.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220616031543.953776-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The minimum priv spec versino for mcountinhibit to v1.11 so that it
is not available for v1.10 (or lower).
Fixes: eab4776b2bad ("target/riscv: Add support for hpmcounters/hpmevents")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220628101737.786681-3-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The riscv_cpu_realize() sets priv spec version to v1.12 when it is
when "env->priv_ver == 0" (i.e. default v1.10) because the enum
value of priv spec v1.10 is zero.
Due to above issue, the sifive_u machine will see priv spec v1.12
instead of priv spec v1.10.
To fix this issue, we set latest priv spec version (i.e. v1.12)
for base rv64/rv32 cpu and riscv_cpu_realize() will override priv
spec version only when "cpu->cfg.priv_spec != NULL".
Fixes: 7100fe6c24 ("target/riscv: Enable privileged spec version 1.12")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20220611080107.391981-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The Ibex CPU supports version 1.11 of the priv spec [1], so let's
correct that in QEMU as well.
1: https://ibex-core.readthedocs.io/en/latest/01_overview/compliance.html
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20220629233102.275181-3-alistair.francis@opensource.wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
There is nothing in the RISC-V spec that mandates version 1.12 is
required for ePMP and there is currently hardware [1] that implements
ePMP (a draft version though) with the 1.11 priv spec.
1: https://ibex-core.readthedocs.io/en/latest/01_overview/compliance.html
Fixes: a4b2fa4331 ("target/riscv: Introduce privilege version field in the CSR ops.")
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20220629233102.275181-2-alistair.francis@opensource.wdc.com>
mcycle/minstret are actually WARL registers and can be written with any
given value. With SBI PMU extension, it will be used to store a initial
value provided from supervisor OS. The Qemu also need prohibit the counter
increment if mcountinhibit is set.
Support mcycle/minstret through generic counter infrastructure.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-8-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
With SBI PMU extension, user can use any of the available hpmcounters to
track any perf events based on the value written to mhpmevent csr.
Add read/write functionality for these csrs.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-7-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
As per the privilege specification v1.11, mcountinhibit allows to start/stop
a pmu counter selectively.
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-6-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The RISC-V privilege specification provides flexibility to implement
any number of counters from 29 programmable counters. However, the QEMU
implements all the counters.
Make it configurable through pmu config parameter which now will indicate
how many programmable counters should be implemented by the cpu.
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-5-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The PMU counters are supported via cpu config "Counters" which doesn't
indicate the correct purpose of those counters.
Rename the config property to pmu to indicate that these counters
are performance monitoring counters. This aligns with cpu options for
ARM architecture as well.
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-4-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Currently, the predicate function for PMU related CSRs only works if
virtualization is enabled. It also does not check mcounteren bits before
before cycle/minstret/hpmcounterx access.
Support supervisor mode access in the predicate function as well.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-3-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The predicate function calculates the counter index incorrectly for
hpmcounterx. Fix the counter index to reflect correct CSR number.
Fixes: e39a8320b0 ("target/riscv: Support the Virtual Instruction fault")
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-2-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
For a TOR entry to match, the stard address must be lower than the end
address. Normally this is always the case, but correct code might still
run into the following scenario:
Initial state:
pmpaddr3 = 0x2000 pmp3cfg = OFF
pmpaddr4 = 0x3000 pmp4cfg = TOR
Execution:
1. write 0x40ff to pmpaddr3
2. write 0x32ff to pmpaddr4
3. set pmp3cfg to NAPOT with a read-modify-write on pmpcfg0
4. set pmp4cfg to NAPOT with a read-modify-write on pmpcfg1
When (2) is emulated, a call to pmp_update_rule() creates a negative
range for pmp4 as pmp4cfg is still set to TOR. And when (3) is emulated,
a call to tlb_flush() is performed, causing pmp_get_tlb_size() to return
a very creatively large TLB size for pmp4. This, in turn, may result in
accesses to non-existent/unitialized memory regions and a fault, so that
(4) ends up never being executed.
This is in m-mode with MPRV unset, meaning that unlocked PMP entries
should have no effect. Therefore such a behavior based on PMP content
is very unexpected.
Make sure no negative PMP range can be created, whether explicitly by
the emulated code or implicitly like the above.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <3oq0sqs1-67o0-145-5n1s-453o118804q@syhkavp.arg>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The set of instructions that require decode_save_opc for
unwinding is really fairly small -- only insns that can
raise ILLEGAL_INSN at runtime. This includes CSR, anything
that uses a *new* fp rounding mode, and many privileged insns.
Since unwind info is stored as the difference from the
previous insn, storing a 0 for most insns minimizes the
size of the unwind info.
Booting a debian kernel image to the missing rootfs panic yields
- gen code size 22226819/1026886656
+ gen code size 21601907/1026886656
on 41k TranslationBlocks, a savings of 610kB or a bit less than 3%.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220604231004.49990-4-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The function doesn't set mtval, it sets badaddr. Move the set
of badaddr directly into gen_exception_inst_addr_mis and use
generate_exception.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220604231004.49990-3-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
While we set env->bins when unwinding for ILLEGAL_INST,
from e.g. csrrw, we weren't setting it for immediately
illegal instructions.
Add a testcase for mtval via both exception paths.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1060
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220604231004.49990-2-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Commit 57c108b864 introduced gen_set_gpri(), which already contains
a check for if the destination register is 'zero'. The check in auipc
and lui are then redundant. This patch removes those checks.
Signed-off-by: Víctor Colombo <victor.colombo@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220610165517.47517-1-victor.colombo@eldorado.org.br>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Move the ARM and RISCV specific helpers into
their own header file.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luc Michel <lmichel@kalray.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Perform the cleanup in the FIXME comment in common_semi_gdb_syscall.
Do not modify guest registers until the syscall is complete,
which in the gdbstub case is asynchronous.
In the synchronous non-gdbstub case, use common_semi_set_ret
to set the result. Merge set_swi_errno into common_semi_cb.
Rely on the latter for combined return value / errno setting.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
When running a 32-bit guest, with a e64 vmv.v.x and vl_eq_vlmax set to
true the `tcg_debug_assert(vece <= MO_32)` will be triggered inside
tcg_gen_gvec_dup_i32().
This patch checks that condition and instead uses tcg_gen_gvec_dup_i64()
is required.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1028
Suggested-by: Robert Bu <robert.bu@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220608234701.369536-1-alistair.francis@opensource.wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
There are currently two types of RISC-V CPUs:
- Generic CPUs (base or any) that allow complete custimisation
- "Named" CPUs that match existing hardware
Users can use the base CPUs to custimise the extensions that they want, for
example -cpu rv64,v=true.
We originally exposed these as part of the named CPUs as well, but that was
by accident.
Exposing the CPU properties to named CPUs means that we accidently
enable extensions that don't exist on the CPUs by default. For example
the SiFive E CPU currently support the zba extension, which is a bug.
This patch instead only exposes the CPU extensions to the generic CPUs.
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20220608061437.314434-1-alistair.francis@opensource.wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
According to v-spec, tail agnostic behavior can be either kept as
undisturbed or set elements' bits to all 1s. To distinguish the
difference of tail policies, QEMU should be able to simulate the tail
agnostic behavior as "set tail 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 tail policies. Setting agnostic elements to
all 1s allows QEMU to express this.
This commit adds option 'rvv_ta_all_1s' is added to enable the
behavior, it is default as disabled.
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: <165449614532.19704.7000832880482980398-16@git.sr.ht>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
