| Message ID | 20250404122858.241598-1-dbarboza@ventanamicro.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [for-10.0] docs: deprecate RISC-V default machine option | expand |
On 4/4/25 14:28, Daniel Henrique Barboza wrote: > Commit 5b4beba124 ("RISC-V Spike Machines") added the Spike machine and > made it default for qemu-system-riscv32/64. It was the first RISC-V > machine added in QEMU so setting it as default was sensible. > > Today we have 7 riscv64 and 6 riscv32 machines and having 'spike' as > default machine is not intuitive. For example, [1] is a bug that was > opened with the 'virt' board in mind, but given that the user didn't > pass a '-machine' option, the user was using 'spike' without knowing. > > Being explicit in the command line is desirable when we have a handful > of boards available, so deprecate the default machine setting from > RISC-V. > > [1] https://gitlab.com/qemu-project/qemu/-/issues/2467 > > Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org> > Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> > --- > docs/about/deprecated.rst | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index 76291fdfd6..0f41a99c67 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -304,6 +304,23 @@ online to check that this board did not completely bitrot yet). It is > recommended to use another MIPS machine for future MIPS code development > instead. > > +RISC-V default machine option (since 10.0) > +'''''''''''''''''''''''''''''''''''''''''' > + > +RISC-V defines ``spike`` as the default machine if no machine option is > +given in the command line. This happens because ``spike`` is the first > +RISC-V machine implemented in QEMU and setting it as default was > +convenient at that time. Now we have 7 riscv64 and 6 riscv32 machines > +and having ``spike`` as a default is no longer justified. This default > +will also promote situations where users think they're running ``virt`` > +(the most used RISC-V machine type in 10.0) when in fact they're > +running ``spike``. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Having users specify "-M virt" doesn't seem much of a hassle IMHO, so I'd not use 'virt' as the /new/ default in 10.2 (but we aren't there yet). > + > +Removing the default machine option forces users to always set the machine > +they want to use and avoids confusion. Existing users of the ``spike`` > +machine must ensure that they're setting the ``spike`` machine in the > +command line (``-M spike``). > +
On 4/4/25 10:07 AM, Philippe Mathieu-Daudé wrote: > On 4/4/25 14:28, Daniel Henrique Barboza wrote: >> Commit 5b4beba124 ("RISC-V Spike Machines") added the Spike machine and >> made it default for qemu-system-riscv32/64. It was the first RISC-V >> machine added in QEMU so setting it as default was sensible. >> >> Today we have 7 riscv64 and 6 riscv32 machines and having 'spike' as >> default machine is not intuitive. For example, [1] is a bug that was >> opened with the 'virt' board in mind, but given that the user didn't >> pass a '-machine' option, the user was using 'spike' without knowing. >> >> Being explicit in the command line is desirable when we have a handful >> of boards available, so deprecate the default machine setting from >> RISC-V. >> >> [1] https://gitlab.com/qemu-project/qemu/-/issues/2467 >> >> Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org> >> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> >> --- >> docs/about/deprecated.rst | 17 +++++++++++++++++ >> 1 file changed, 17 insertions(+) >> >> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst >> index 76291fdfd6..0f41a99c67 100644 >> --- a/docs/about/deprecated.rst >> +++ b/docs/about/deprecated.rst >> @@ -304,6 +304,23 @@ online to check that this board did not completely bitrot yet). It is >> recommended to use another MIPS machine for future MIPS code development >> instead. >> +RISC-V default machine option (since 10.0) >> +'''''''''''''''''''''''''''''''''''''''''' >> + >> +RISC-V defines ``spike`` as the default machine if no machine option is >> +given in the command line. This happens because ``spike`` is the first >> +RISC-V machine implemented in QEMU and setting it as default was >> +convenient at that time. Now we have 7 riscv64 and 6 riscv32 machines >> +and having ``spike`` as a default is no longer justified. This default >> +will also promote situations where users think they're running ``virt`` >> +(the most used RISC-V machine type in 10.0) when in fact they're >> +running ``spike``. > > Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> > > Having users specify "-M virt" doesn't seem much of a hassle IMHO, > so I'd not use 'virt' as the /new/ default in 10.2 (but we aren't > there yet). The idea is to not have any default machine at all. Users will need to specify "-M <machine_name>" in the command line for all RISC-V machines. Otherwise we might run in the same problem again if another RISC-V board becomes more popular than 'virt'. Thanks, Daniel > >> + >> +Removing the default machine option forces users to always set the machine >> +they want to use and avoids confusion. Existing users of the ``spike`` >> +machine must ensure that they're setting the ``spike`` machine in the >> +command line (``-M spike``). >> +
On 4/4/25 05:28, Daniel Henrique Barboza wrote: > Commit 5b4beba124 ("RISC-V Spike Machines") added the Spike machine and > made it default for qemu-system-riscv32/64. It was the first RISC-V > machine added in QEMU so setting it as default was sensible. > > Today we have 7 riscv64 and 6 riscv32 machines and having 'spike' as > default machine is not intuitive. For example, [1] is a bug that was > opened with the 'virt' board in mind, but given that the user didn't > pass a '-machine' option, the user was using 'spike' without knowing. > > Being explicit in the command line is desirable when we have a handful > of boards available, so deprecate the default machine setting from > RISC-V. > > [1]https://gitlab.com/qemu-project/qemu/-/issues/2467 > > Suggested-by: Philippe Mathieu-Daudé<philmd@linaro.org> > Signed-off-by: Daniel Henrique Barboza<dbarboza@ventanamicro.com> > --- > docs/about/deprecated.rst | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 76291fdfd6..0f41a99c67 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -304,6 +304,23 @@ online to check that this board did not completely bitrot yet). It is recommended to use another MIPS machine for future MIPS code development instead. +RISC-V default machine option (since 10.0) +'''''''''''''''''''''''''''''''''''''''''' + +RISC-V defines ``spike`` as the default machine if no machine option is +given in the command line. This happens because ``spike`` is the first +RISC-V machine implemented in QEMU and setting it as default was +convenient at that time. Now we have 7 riscv64 and 6 riscv32 machines +and having ``spike`` as a default is no longer justified. This default +will also promote situations where users think they're running ``virt`` +(the most used RISC-V machine type in 10.0) when in fact they're +running ``spike``. + +Removing the default machine option forces users to always set the machine +they want to use and avoids confusion. Existing users of the ``spike`` +machine must ensure that they're setting the ``spike`` machine in the +command line (``-M spike``). + Backend options ---------------
Commit 5b4beba124 ("RISC-V Spike Machines") added the Spike machine and made it default for qemu-system-riscv32/64. It was the first RISC-V machine added in QEMU so setting it as default was sensible. Today we have 7 riscv64 and 6 riscv32 machines and having 'spike' as default machine is not intuitive. For example, [1] is a bug that was opened with the 'virt' board in mind, but given that the user didn't pass a '-machine' option, the user was using 'spike' without knowing. Being explicit in the command line is desirable when we have a handful of boards available, so deprecate the default machine setting from RISC-V. [1] https://gitlab.com/qemu-project/qemu/-/issues/2467 Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> --- docs/about/deprecated.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)