Commit 3b8022269c added the capability of named features/profile
extensions to be added in riscv,isa. To do that we had to assign priv
versions for each one of them in isa_edata_arr[]. But this resulted in a
side-effect: vendor CPUs that aren't running priv_version_latest started
to experience warnings for these profile extensions [1]:
| $ qemu-system-riscv32 -M sifive_e
| qemu-system-riscv32: warning: disabling zic64b extension for hart
0x00000000 because privilege spec version does not match
| qemu-system-riscv32: warning: disabling ziccamoa extension for
hart 0x00000000 because privilege spec version does not match
This is benign as far as the CPU behavior is concerned since disabling
both extensions is a no-op (aside from riscv,isa). But the warnings are
unpleasant to deal with, especially because we're sending user warnings
for extensions that users can't enable/disable.
Instead of enabling all named features all the time, separate them by
priv version. During finalize() time, after we decided which
priv_version the CPU is running, enable/disable all the named extensions
based on the priv spec chosen. This will be enough for a bug fix, but as
a future work we should look into how we can name these extensions in a
way that we don't need an explicit ext_name => priv_ver as we're doing
here.
The named extensions being added in isa_edata_arr[] that will be
enabled/disabled based solely on priv version can be removed from
riscv_cpu_named_features[]. 'zic64b' is an extension that can be
disabled based on block sizes so it'll retain its own flag and entry.
[1] https://lists.gnu.org/archive/html/qemu-devel/2024-03/msg02592.html
Reported-by: Clément Chigot <chigot@adacore.com>
Fixes: 3b8022269c ("target/riscv: add riscv,isa to named features")
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Tested-by: Clément Chigot <chigot@adacore.com>
Message-ID: <20240312203214.350980-1-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Since CPU() macro is a simple cast, the following are equivalent:
Object *obj;
CPUState *cs = CPU(obj)
In order to ease static analysis when running
scripts/coccinelle/cpu_env.cocci from the previous commit,
replace:
- CPU_GET_CLASS(cpu);
+ CPU_GET_CLASS(obj);
Most code use the 'cs' variable name for CPUState handle.
Replace few 's' -> 'cs' to unify cpu_reset_hold() style.
No logical change in this patch.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240129164514.73104-7-philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.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>
Named features are extensions which don't make sense for users to
control and are therefore not exposed on the command line. However,
svade is an extension which makes sense for users to control, so treat
it like a "normal" extension. The default is false, even for the max
cpu type, since QEMU has always implemented hardware A/D PTE bit
updating, so users must opt into svade (or get it from a CPU type
which enables it by default).
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240215223955.969568-7-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Gate hardware A/D PTE bit updating on {m,h}envcfg.ADUE and only
enable menvcfg.ADUE on reset if svade has not been selected. Now
that we also consider svade, we have four possible configurations:
1) !svade && !svadu
use hardware updating and there's no way to disable it
(the default, which maintains past behavior. Maintaining
the default, even with !svadu is a change that fixes [1])
2) !svade && svadu
use hardware updating, but also provide {m,h}envcfg.ADUE,
allowing software to switch to exception mode
(being able to switch is a change which fixes [1])
3) svade && !svadu
use exception mode and there's no way to switch to hardware
updating
(this behavior change fixes [2])
4) svade && svadu
use exception mode, but also provide {m,h}envcfg.ADUE,
allowing software to switch to hardware updating
(this behavior change fixes [2])
Fixes: 0af3f115e6 ("target/riscv: Add *envcfg.HADE related check in address translation") [1]
Fixes: 48531f5adb ("target/riscv: implement svade") [2]
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240215223955.969568-6-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The RVA22U64 and RVA22S64 profiles mandates certain extensions that,
until now, we were implying that they were available.
We can't do this anymore since named features also has a riscv,isa
entry. Let's add them to riscv_cpu_named_features[].
Instead of adding one bool for each named feature that we'll always
implement, i.e. can't be turned off, add a 'ext_always_enabled' bool in
cpu->cfg. This bool will be set to 'true' in TCG accel init, and all
named features will point to it. This also means that KVM won't see
these features as always enable, which is our intention.
If any accelerator adds support to disable one of these features, we'll
have to promote them to regular extensions and allow users to disable it
via command line.
After this patch, here's the riscv,isa from a buildroot using the
'rva22s64' CPU:
# cat /proc/device-tree/cpus/cpu@0/riscv,isa
rv64imafdc_zic64b_zicbom_zicbop_zicboz_ziccamoa_ziccif_zicclsm_ziccrse_
zicntr_zicsr_zifencei_zihintpause_zihpm_za64rs_zfhmin_zca_zcd_zba_zbb_
zbs_zkt_ssccptr_sscounterenw_sstvala_sstvecd_svade_svinval_svpbmt#
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-ID: <20240215223955.969568-4-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Further discussions after the introduction of rva22 support in QEMU
revealed that what we've been calling 'named features' are actually
regular extensions, with their respective riscv,isa DTs. This is
clarified in [1]. [2] is a bug tracker asking for the profile spec to be
less cryptic about it.
As far as QEMU goes we understand extensions as something that the user
can enable/disable in the command line. This isn't the case for named
features, so we'll have to reach a middle ground.
We'll keep our existing nomenclature 'named features' to refer to any
extension that the user can't control in the command line. We'll also do
the following:
- 'svade' and 'zic64b' flags are renamed to 'ext_svade' and
'ext_zic64b'. 'ext_svade' and 'ext_zic64b' now have riscv,isa strings and
priv_spec versions;
- skip name feature check in cpu_bump_multi_ext_priv_ver(). Now that
named features have a riscv,isa and an entry in isa_edata_arr[] we
don't need to gate the call to cpu_cfg_ext_get_min_version() anymore.
[1] https://github.com/riscv/riscv-profiles/issues/121
[2] https://github.com/riscv/riscv-profiles/issues/142
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240215223955.969568-3-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
A bare bones 32 bit RVI CPU, rv32i, will make users lives easier when a
full customized 32 bit CPU is desired, and users won't need to disable
defaults by hand as they would with the rv32 CPU. [1] has an example of
a situation that would be avoided with rv32i.
In fact, add bare bones CPUs for RVE as well. Trying to use RVE in QEMU
requires one to disable every single default extension, including RVI,
and then add the desirable extension set. Adding rv32e/rv64e makes it
more pleasant to use embedded CPUs in QEMU.
[1] https://lore.kernel.org/qemu-riscv/258be47f-97be-4308-bed5-dc34ef7ff954@Spark/
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240122123348.973288-3-dbarboza@ventanamicro.com>
[ Changes by AF:
- Rebase on latest changes
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Next patch will add more bare CPUs. Their cpu_init() functions would be
glorified copy/pastes of rv64i_bare_cpu_init(), differing only by a
riscv_cpu_set_misa() call.
Add a new .instance_init for the TYPE_RISCV_BARE_CPU typ to avoid this
code repetition. While we're at it, add a better explanation on why
we're disabling the timing extensions for bare CPUs.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240122123348.973288-2-dbarboza@ventanamicro.com>
[ Changes by AF:
- Rebase on latest changes
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
A few months ago I submitted a patch to various lists, deprecating
"riscv,isa" with a lengthy commit message [0] that is now commit
aeb71e42caae ("dt-bindings: riscv: deprecate riscv,isa") in the Linux
kernel tree. Primarily, the goal was to replace "riscv,isa" with a new
set of properties that allowed for strictly defining the meaning of
various extensions, where "riscv,isa" was tied to whatever definitions
inflicted upon us by the ISA manual, which have seen some variance over
time.
Two new properties were introduced: "riscv,isa-base" and
"riscv,isa-extensions". The former is a simple string to communicate the
base ISA implemented by a hart and the latter an array of strings used
to communicate the set of ISA extensions supported, per the definitions
of each substring in extensions.yaml [1]. A beneficial side effect was
also the ability to define vendor extensions in a more "official" way,
as the ISA manual and other RVI specifications only covered the format
for vendor extensions in the ISA string, but not the meaning of vendor
extensions, for obvious reasons.
Add support for setting these two new properties in the devicetrees for
the various devicetree platforms supported by QEMU for RISC-V. The Linux
kernel already supports parsing ISA extensions from these new
properties, and documenting them in the dt-binding is a requirement for
new extension detection being added to the kernel.
A side effect of the implementation is that the meaning for elements in
"riscv,isa" and in "riscv,isa-extensions" are now tied together as they
are constructed from the same source. The same applies to the ISA string
provided in ACPI tables, but there does not appear to be any strict
definitions of meanings in ACPI land either.
Link: https://lore.kernel.org/qemu-riscv/20230702-eats-scorebook-c951f170d29f@spud/ [0]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/riscv/extensions.yaml [1]
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20240124-unvarying-foothold-9dde2aaf95d4@spud>
[ Changes by AF:
- Rebase on recent changes
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Our usage of 'vlenb' is overwhelming superior than the use of 'vlen'.
We're using 'vlenb' most of the time, having to do 'vlen >> 3' or
'vlen / 8' in every instance.
In hindsight we would be better if the 'vlenb' property was introduced
instead of 'vlen'. That's not what happened, and now we can't easily get
rid of it due to user scripts all around. What we can do, however, is to
change our internal representation to use 'vlenb'.
Add a 'vlenb' field in cpu->cfg. It'll be set via the existing 'vlen'
property, i.e. setting 'vlen' will also set 'vlenb'.
We'll replace all 'vlen >> 3' code to use 'vlenb' directly. Start with
the single instance we have in target/riscv/cpu.c.
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: <20240122161107.26737-2-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
