| Message ID | 20210123021950.1270-1-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] xen: EXPERT clean-up and introduce UNSUPPORTED | expand |
On 23.01.2021 03:19, Stefano Stabellini wrote: > --- a/xen/Kconfig > +++ b/xen/Kconfig > @@ -34,8 +34,15 @@ config DEFCONFIG_LIST > option defconfig_list > default ARCH_DEFCONFIG > > +config UNSUPPORTED > + bool "Configure UNSUPPORTED features" > + help > + This option allows certain unsupported Xen options to be changed, > + which includes non-security-supported, experimental, and tech > + preview features as defined by SUPPORT.md. And by implication anything not depending on UNSUPPORTED is supported? I didn't think this was the case (some unsupported code can't even be turned off via Kconfig), so I think this needs clarifying here, so we won't end up with people considering some feature supported which really isn't. That's irrespective of the reference to SUPPORT.md. > config EXPERT > - bool "Configure standard Xen features (expert users)" > + bool "Configure EXPERT features" > help > This option allows certain base Xen options and settings > to be disabled or tweaked. This is for specialized environments I'd like to suggest to move UNSUPPORTED past this one, to then have that have "default EXPERT". Jan
Hi Stefano, > On 23 Jan 2021, at 02:19, Stefano Stabellini <sstabellini@kernel.org> wrote: > > A recent thread [1] has exposed a couple of issues with our current way > of handling EXPERT. > > 1) It is not obvious that "Configure standard Xen features (expert > users)" is actually the famous EXPERT we keep talking about on xen-devel > > 2) It is not obvious when we need to enable EXPERT to get a specific > feature > > In particular if you want to enable ACPI support so that you can boot > Xen on an ACPI platform, you have to enable EXPERT first. But searching > through the kconfig menu it is really not clear (type '/' and "ACPI"): > nothing in the description tells you that you need to enable EXPERT to > get the option. > > So this patch makes things easier by doing two things: > > - introduce a new kconfig option UNSUPPORTED which is clearly to enable > UNSUPPORTED features as defined by SUPPORT.md That’s a great change which will improve user experience. > > - change EXPERT options to UNSUPPORTED where it makes sense: keep > depending on EXPERT for features made for experts > > - tag unsupported features by adding (UNSUPPORTED) to the one-line > description > Shouldn’t we add (EXPERT) for expert options in the same way for coherency ? Cheers Bertrand > - clarify the EXPERT one-line description > > [1] https://marc.info/?l=xen-devel&m=160333101228981 > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > CC: andrew.cooper3@citrix.com > CC: george.dunlap@citrix.com > CC: iwj@xenproject.org > CC: jbeulich@suse.com > CC: julien@xen.org > CC: wl@xen.org > CC: Bertrand.Marquis@arm.com > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > --- > Changes in v3: > - improve UNSUPPORTED text description > - avoid changing XEN_SHSTK and EFI_SET_VIRTUAL_ADDRESS_MAP > - update HVM_FEP to be UNSUPPORTED > > Changes in v2: > - introduce UNSUPPORTED > - don't switch all EXPERT options to UNSUPPORTED > > See as reference the v2 thread here: > https://marc.info/?l=xen-devel&m=160566066013723 > --- > xen/Kconfig | 9 ++++++++- > xen/arch/arm/Kconfig | 10 +++++----- > xen/arch/x86/Kconfig | 6 +++--- > xen/common/Kconfig | 2 +- > xen/common/sched/Kconfig | 6 +++--- > 5 files changed, 20 insertions(+), 13 deletions(-) > > diff --git a/xen/Kconfig b/xen/Kconfig > index 34c318bfa2..4a3d988353 100644 > --- a/xen/Kconfig > +++ b/xen/Kconfig > @@ -34,8 +34,15 @@ config DEFCONFIG_LIST > option defconfig_list > default ARCH_DEFCONFIG > > +config UNSUPPORTED > + bool "Configure UNSUPPORTED features" > + help > + This option allows certain unsupported Xen options to be changed, > + which includes non-security-supported, experimental, and tech > + preview features as defined by SUPPORT.md. > + > config EXPERT > - bool "Configure standard Xen features (expert users)" > + bool "Configure EXPERT features" > help > This option allows certain base Xen options and settings > to be disabled or tweaked. This is for specialized environments > diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig > index c3eb13ea73..cca76040e5 100644 > --- a/xen/arch/arm/Kconfig > +++ b/xen/arch/arm/Kconfig > @@ -32,7 +32,7 @@ menu "Architecture Features" > source "arch/Kconfig" > > config ACPI > - bool "ACPI (Advanced Configuration and Power Interface) Support" if EXPERT > + bool "ACPI (Advanced Configuration and Power Interface) Support (UNSUPPORTED)" if UNSUPPORTED > depends on ARM_64 > ---help--- > > @@ -49,7 +49,7 @@ config GICV3 > If unsure, say Y > > config HAS_ITS > - bool "GICv3 ITS MSI controller support" if EXPERT > + bool "GICv3 ITS MSI controller support (UNSUPPORTED)" if UNSUPPORTED > depends on GICV3 && !NEW_VGIC > > config HVM > @@ -77,7 +77,7 @@ config SBSA_VUART_CONSOLE > SBSA Generic UART implements a subset of ARM PL011 UART. > > config ARM_SSBD > - bool "Speculative Store Bypass Disable" if EXPERT > + bool "Speculative Store Bypass Disable (UNSUPPORTED)" if UNSUPPORTED > depends on HAS_ALTERNATIVE > default y > help > @@ -87,7 +87,7 @@ config ARM_SSBD > If unsure, say Y. > > config HARDEN_BRANCH_PREDICTOR > - bool "Harden the branch predictor against aliasing attacks" if EXPERT > + bool "Harden the branch predictor against aliasing attacks (UNSUPPORTED)" if UNSUPPORTED > default y > help > Speculation attacks against some high-performance processors rely on > @@ -104,7 +104,7 @@ config HARDEN_BRANCH_PREDICTOR > If unsure, say Y. > > config TEE > - bool "Enable TEE mediators support" if EXPERT > + bool "Enable TEE mediators support (UNSUPPORTED)" if UNSUPPORTED > default n > help > This option enables generic TEE mediators support. It allows guests > diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig > index 78f351f94b..302334d3e4 100644 > --- a/xen/arch/x86/Kconfig > +++ b/xen/arch/x86/Kconfig > @@ -147,7 +147,7 @@ config BIGMEM > If unsure, say N. > > config HVM_FEP > - bool "HVM Forced Emulation Prefix support" if EXPERT > + bool "HVM Forced Emulation Prefix support (UNSUPPORTED)" if UNSUPPORTED > default DEBUG > depends on HVM > ---help--- > @@ -166,7 +166,7 @@ config HVM_FEP > If unsure, say N. > > config TBOOT > - bool "Xen tboot support" if EXPERT > + bool "Xen tboot support (UNSUPPORTED)" if UNSUPPORTED > default y if !PV_SHIM_EXCLUSIVE > select CRYPTO > ---help--- > @@ -252,7 +252,7 @@ config HYPERV_GUEST > endif > > config MEM_SHARING > - bool "Xen memory sharing support" if EXPERT > + bool "Xen memory sharing support (UNSUPPORTED)" if UNSUPPORTED > depends on HVM > > endmenu > diff --git a/xen/common/Kconfig b/xen/common/Kconfig > index b5c91a1664..39451e8350 100644 > --- a/xen/common/Kconfig > +++ b/xen/common/Kconfig > @@ -272,7 +272,7 @@ config LATE_HWDOM > If unsure, say N. > > config ARGO > - bool "Argo: hypervisor-mediated interdomain communication" if EXPERT > + bool "Argo: hypervisor-mediated interdomain communication (UNSUPPORTED)" if UNSUPPORTED > ---help--- > Enables a hypercall for domains to ask the hypervisor to perform > data transfer of messages between domains. > diff --git a/xen/common/sched/Kconfig b/xen/common/sched/Kconfig > index 61231aacaa..94c9e20139 100644 > --- a/xen/common/sched/Kconfig > +++ b/xen/common/sched/Kconfig > @@ -15,7 +15,7 @@ config SCHED_CREDIT2 > optimized for lower latency and higher VM density. > > config SCHED_RTDS > - bool "RTDS scheduler support (EXPERIMENTAL)" > + bool "RTDS scheduler support (UNSUPPORTED)" if UNSUPPORTED > default y > ---help--- > The RTDS scheduler is a soft and firm real-time scheduler for > @@ -23,14 +23,14 @@ config SCHED_RTDS > in the cloud, and general low-latency workloads. > > config SCHED_ARINC653 > - bool "ARINC653 scheduler support (EXPERIMENTAL)" > + bool "ARINC653 scheduler support (UNSUPPORTED)" if UNSUPPORTED > default DEBUG > ---help--- > The ARINC653 scheduler is a hard real-time scheduler for single > cores, targeted for avionics, drones, and medical devices. > > config SCHED_NULL > - bool "Null scheduler support (EXPERIMENTAL)" > + bool "Null scheduler support (UNSUPPORTED)" if UNSUPPORTED > default y > ---help--- > The null scheduler is a static, zero overhead scheduler, > -- > 2.17.1 >
On Mon, 25 Jan 2021, Jan Beulich wrote: > On 23.01.2021 03:19, Stefano Stabellini wrote: > > --- a/xen/Kconfig > > +++ b/xen/Kconfig > > @@ -34,8 +34,15 @@ config DEFCONFIG_LIST > > option defconfig_list > > default ARCH_DEFCONFIG > > > > +config UNSUPPORTED > > + bool "Configure UNSUPPORTED features" > > + help > > + This option allows certain unsupported Xen options to be changed, > > + which includes non-security-supported, experimental, and tech > > + preview features as defined by SUPPORT.md. > > And by implication anything not depending on UNSUPPORTED is > supported? I didn't think this was the case (some unsupported > code can't even be turned off via Kconfig), so I think this > needs clarifying here, so we won't end up with people > considering some feature supported which really isn't. That's > irrespective of the reference to SUPPORT.md. I'll clarify. > > config EXPERT > > - bool "Configure standard Xen features (expert users)" > > + bool "Configure EXPERT features" > > help > > This option allows certain base Xen options and settings > > to be disabled or tweaked. This is for specialized environments > > I'd like to suggest to move UNSUPPORTED past this one, to > then have that have "default EXPERT". Sure, good idea.
On Mon, 25 Jan 2021, Bertrand Marquis wrote: > Hi Stefano, > > > On 23 Jan 2021, at 02:19, Stefano Stabellini <sstabellini@kernel.org> wrote: > > > > A recent thread [1] has exposed a couple of issues with our current way > > of handling EXPERT. > > > > 1) It is not obvious that "Configure standard Xen features (expert > > users)" is actually the famous EXPERT we keep talking about on xen-devel > > > > 2) It is not obvious when we need to enable EXPERT to get a specific > > feature > > > > In particular if you want to enable ACPI support so that you can boot > > Xen on an ACPI platform, you have to enable EXPERT first. But searching > > through the kconfig menu it is really not clear (type '/' and "ACPI"): > > nothing in the description tells you that you need to enable EXPERT to > > get the option. > > > > So this patch makes things easier by doing two things: > > > > - introduce a new kconfig option UNSUPPORTED which is clearly to enable > > UNSUPPORTED features as defined by SUPPORT.md > > That’s a great change which will improve user experience. Thank you! > > - change EXPERT options to UNSUPPORTED where it makes sense: keep > > depending on EXPERT for features made for experts > > > > - tag unsupported features by adding (UNSUPPORTED) to the one-line > > description > > > > Shouldn’t we add (EXPERT) for expert options in the same way for coherency ? I take you mean add "(EXPERT)" to the one-line description in kconfig. I am OK with that, probably better as a second separate patch. I'll add it.
diff --git a/xen/Kconfig b/xen/Kconfig index 34c318bfa2..4a3d988353 100644 --- a/xen/Kconfig +++ b/xen/Kconfig @@ -34,8 +34,15 @@ config DEFCONFIG_LIST option defconfig_list default ARCH_DEFCONFIG +config UNSUPPORTED + bool "Configure UNSUPPORTED features" + help + This option allows certain unsupported Xen options to be changed, + which includes non-security-supported, experimental, and tech + preview features as defined by SUPPORT.md. + config EXPERT - bool "Configure standard Xen features (expert users)" + bool "Configure EXPERT features" help This option allows certain base Xen options and settings to be disabled or tweaked. This is for specialized environments diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index c3eb13ea73..cca76040e5 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -32,7 +32,7 @@ menu "Architecture Features" source "arch/Kconfig" config ACPI - bool "ACPI (Advanced Configuration and Power Interface) Support" if EXPERT + bool "ACPI (Advanced Configuration and Power Interface) Support (UNSUPPORTED)" if UNSUPPORTED depends on ARM_64 ---help--- @@ -49,7 +49,7 @@ config GICV3 If unsure, say Y config HAS_ITS - bool "GICv3 ITS MSI controller support" if EXPERT + bool "GICv3 ITS MSI controller support (UNSUPPORTED)" if UNSUPPORTED depends on GICV3 && !NEW_VGIC config HVM @@ -77,7 +77,7 @@ config SBSA_VUART_CONSOLE SBSA Generic UART implements a subset of ARM PL011 UART. config ARM_SSBD - bool "Speculative Store Bypass Disable" if EXPERT + bool "Speculative Store Bypass Disable (UNSUPPORTED)" if UNSUPPORTED depends on HAS_ALTERNATIVE default y help @@ -87,7 +87,7 @@ config ARM_SSBD If unsure, say Y. config HARDEN_BRANCH_PREDICTOR - bool "Harden the branch predictor against aliasing attacks" if EXPERT + bool "Harden the branch predictor against aliasing attacks (UNSUPPORTED)" if UNSUPPORTED default y help Speculation attacks against some high-performance processors rely on @@ -104,7 +104,7 @@ config HARDEN_BRANCH_PREDICTOR If unsure, say Y. config TEE - bool "Enable TEE mediators support" if EXPERT + bool "Enable TEE mediators support (UNSUPPORTED)" if UNSUPPORTED default n help This option enables generic TEE mediators support. It allows guests diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig index 78f351f94b..302334d3e4 100644 --- a/xen/arch/x86/Kconfig +++ b/xen/arch/x86/Kconfig @@ -147,7 +147,7 @@ config BIGMEM If unsure, say N. config HVM_FEP - bool "HVM Forced Emulation Prefix support" if EXPERT + bool "HVM Forced Emulation Prefix support (UNSUPPORTED)" if UNSUPPORTED default DEBUG depends on HVM ---help--- @@ -166,7 +166,7 @@ config HVM_FEP If unsure, say N. config TBOOT - bool "Xen tboot support" if EXPERT + bool "Xen tboot support (UNSUPPORTED)" if UNSUPPORTED default y if !PV_SHIM_EXCLUSIVE select CRYPTO ---help--- @@ -252,7 +252,7 @@ config HYPERV_GUEST endif config MEM_SHARING - bool "Xen memory sharing support" if EXPERT + bool "Xen memory sharing support (UNSUPPORTED)" if UNSUPPORTED depends on HVM endmenu diff --git a/xen/common/Kconfig b/xen/common/Kconfig index b5c91a1664..39451e8350 100644 --- a/xen/common/Kconfig +++ b/xen/common/Kconfig @@ -272,7 +272,7 @@ config LATE_HWDOM If unsure, say N. config ARGO - bool "Argo: hypervisor-mediated interdomain communication" if EXPERT + bool "Argo: hypervisor-mediated interdomain communication (UNSUPPORTED)" if UNSUPPORTED ---help--- Enables a hypercall for domains to ask the hypervisor to perform data transfer of messages between domains. diff --git a/xen/common/sched/Kconfig b/xen/common/sched/Kconfig index 61231aacaa..94c9e20139 100644 --- a/xen/common/sched/Kconfig +++ b/xen/common/sched/Kconfig @@ -15,7 +15,7 @@ config SCHED_CREDIT2 optimized for lower latency and higher VM density. config SCHED_RTDS - bool "RTDS scheduler support (EXPERIMENTAL)" + bool "RTDS scheduler support (UNSUPPORTED)" if UNSUPPORTED default y ---help--- The RTDS scheduler is a soft and firm real-time scheduler for @@ -23,14 +23,14 @@ config SCHED_RTDS in the cloud, and general low-latency workloads. config SCHED_ARINC653 - bool "ARINC653 scheduler support (EXPERIMENTAL)" + bool "ARINC653 scheduler support (UNSUPPORTED)" if UNSUPPORTED default DEBUG ---help--- The ARINC653 scheduler is a hard real-time scheduler for single cores, targeted for avionics, drones, and medical devices. config SCHED_NULL - bool "Null scheduler support (EXPERIMENTAL)" + bool "Null scheduler support (UNSUPPORTED)" if UNSUPPORTED default y ---help--- The null scheduler is a static, zero overhead scheduler,