| Message ID | 20240104205959.4128825-2-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Replace CONFIG_HAVE_KVM with more appropriate symbols. | expand |
On Thu, Jan 04, 2024 at 03:59:56PM -0500, Paolo Bonzini wrote: > CONFIG_HAVE_KVM is currently used by some architectures to either > enabled the KVM config proper, or to enable host-side code that is > not part of the KVM module. However, the "select" statement in > virt/kvm/Kconfig corresponds to a third meaning, namely to > enable common Kconfigs required by all architectures that support > KVM. > > These three meanings can be replaced respectively by an > architecture-specific Kconfig, by IS_ENABLED(CONFIG_KVM), or by > a new Kconfig symbol that is in turn selected by the > architecture-specific "config KVM". > > Start by introducing such a new Kconfig symbol, CONFIG_KVM_COMMON. > Unlike CONFIG_HAVE_KVM, it is selected by CONFIG_KVM, not by > architecture code. > > Fixes: 8132d887a702 ("KVM: remove CONFIG_HAVE_KVM_EVENTFD", 2023-12-08) > Cc: Andrew Jones <ajones@ventanamicro.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/arm64/kvm/Kconfig | 1 + > arch/loongarch/kvm/Kconfig | 1 + > arch/mips/kvm/Kconfig | 1 + > arch/powerpc/kvm/Kconfig | 1 + > arch/riscv/kvm/Kconfig | 1 + > arch/s390/kvm/Kconfig | 1 + > arch/x86/kvm/Kconfig | 1 + > virt/kvm/Kconfig | 3 +++ > 8 files changed, 10 insertions(+) Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
On Thu, Jan 04, 2024, Paolo Bonzini wrote: > CONFIG_HAVE_KVM is currently used by some architectures to either > enabled the KVM config proper, or to enable host-side code that is > not part of the KVM module. However, the "select" statement in > virt/kvm/Kconfig corresponds to a third meaning, namely to > enable common Kconfigs required by all architectures that support > KVM. > > These three meanings can be replaced respectively by an > architecture-specific Kconfig, by IS_ENABLED(CONFIG_KVM), or by > a new Kconfig symbol that is in turn selected by the > architecture-specific "config KVM". > > Start by introducing such a new Kconfig symbol, CONFIG_KVM_COMMON. > Unlike CONFIG_HAVE_KVM, it is selected by CONFIG_KVM, not by > architecture code. Why? I don't get it, just have code that cares do IS_ENABLED(CONFIG_KVM). Except for the MIPS usage of HAVE_KVM that you solved by adding CPU_SUPPORTS_VZ, I got all the way there using just CONFIG_KVM[*]. Ah, and so does this series for the most part, the only usage of CONFIG_KVM_COMMON is in scripts/gdb/linux/constants.py.in. Honestly, adding a Kconfig just so that VMX's posted interrupts that arrive in the host can be printed when KVM is built as a module is a waste of a Kconfig. [*] https://lore.kernel.org/all/20230916003118.2540661-12-seanjc@google.com
On Fri, Jan 5, 2024 at 8:13 PM Sean Christopherson <seanjc@google.com> wrote: > > Start by introducing such a new Kconfig symbol, CONFIG_KVM_COMMON. > > Unlike CONFIG_HAVE_KVM, it is selected by CONFIG_KVM, not by > > architecture code. > > Why? I don't get it, just have code that cares do IS_ENABLED(CONFIG_KVM). Except > for the MIPS usage of HAVE_KVM that you solved by adding CPU_SUPPORTS_VZ, I got > all the way there using just CONFIG_KVM[*]. > > Ah, and so does this series for the most part, the only usage of CONFIG_KVM_COMMON > is in scripts/gdb/linux/constants.py.in. Honestly, adding a Kconfig just so that > VMX's posted interrupts that arrive in the host can be printed when KVM is built > as a module is a waste of a Kconfig. There is one extra thing that CONFIG_KVM_COMMON does, which is to avoid having to select common requirements in all architectures. I jotted this to solve the reported randconfig failure, which is why CONFIG_KVM_COMMON only requires "select EVENTFD", but looking more closely it should also select PREEMPT_NOTIFIERS and INTERVAL_TREE. Both are used by virt/kvm/kvm_main.c, and loongarch + riscv both lack INTERVAL_TREE so I do think it's a good idea to introduce this symbol (though it requires a v2). > [*] https://lore.kernel.org/all/20230916003118.2540661-12-seanjc@google.com I guess you mean https://lore.kernel.org/all/20230916003118.2540661-8-seanjc@google.com/. Paolo
On Fri, Jan 05, 2024, Paolo Bonzini wrote: > On Fri, Jan 5, 2024 at 8:13 PM Sean Christopherson <seanjc@google.com> wrote: > > > Start by introducing such a new Kconfig symbol, CONFIG_KVM_COMMON. > > > Unlike CONFIG_HAVE_KVM, it is selected by CONFIG_KVM, not by > > > architecture code. > > > > Why? I don't get it, just have code that cares do IS_ENABLED(CONFIG_KVM). Except > > for the MIPS usage of HAVE_KVM that you solved by adding CPU_SUPPORTS_VZ, I got > > all the way there using just CONFIG_KVM[*]. > > > > Ah, and so does this series for the most part, the only usage of CONFIG_KVM_COMMON > > is in scripts/gdb/linux/constants.py.in. Honestly, adding a Kconfig just so that > > VMX's posted interrupts that arrive in the host can be printed when KVM is built > > as a module is a waste of a Kconfig. > > There is one extra thing that CONFIG_KVM_COMMON does, which is to > avoid having to select common requirements in all architectures. Oooh, gotcha. FWIW, I would love to unify the "menuconfig VIRTUALIZATION" and "config KVM" entries, but I can't think of a sane way to do that without ending up with something like KVM_COMMON. :-/ > I jotted this to solve the reported randconfig failure, which is why > CONFIG_KVM_COMMON only requires "select EVENTFD", but looking more > closely it should also select PREEMPT_NOTIFIERS and INTERVAL_TREE. > Both are used by virt/kvm/kvm_main.c, and loongarch + riscv both lack > INTERVAL_TREE so I do think it's a good idea to introduce this symbol > (though it requires a v2). > > > [*] https://lore.kernel.org/all/20230916003118.2540661-12-seanjc@google.com > > I guess you mean > https://lore.kernel.org/all/20230916003118.2540661-8-seanjc@google.com/. Doh, yes.
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index b07c60c9737d..ad5ce0454f17 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -21,6 +21,7 @@ if VIRTUALIZATION menuconfig KVM bool "Kernel-based Virtual Machine (KVM) support" depends on HAVE_KVM + select KVM_COMMON select KVM_GENERIC_HARDWARE_ENABLING select KVM_GENERIC_MMU_NOTIFIER select PREEMPT_NOTIFIERS diff --git a/arch/loongarch/kvm/Kconfig b/arch/loongarch/kvm/Kconfig index daba4cd5e87d..3b284b7e63ad 100644 --- a/arch/loongarch/kvm/Kconfig +++ b/arch/loongarch/kvm/Kconfig @@ -23,6 +23,7 @@ config KVM depends on HAVE_KVM select HAVE_KVM_DIRTY_RING_ACQ_REL select HAVE_KVM_VCPU_ASYNC_IOCTL + select KVM_COMMON select KVM_GENERIC_DIRTYLOG_READ_PROTECT select KVM_GENERIC_HARDWARE_ENABLING select KVM_GENERIC_MMU_NOTIFIER diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig index 428141b0b48f..2eb119e78b6e 100644 --- a/arch/mips/kvm/Kconfig +++ b/arch/mips/kvm/Kconfig @@ -21,6 +21,7 @@ config KVM depends on MIPS_FP_SUPPORT select EXPORT_UASM select PREEMPT_NOTIFIERS + select KVM_COMMON select KVM_GENERIC_DIRTYLOG_READ_PROTECT select HAVE_KVM_VCPU_ASYNC_IOCTL select KVM_MMIO diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index b47196085a42..5da535e20b6a 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -20,6 +20,7 @@ if VIRTUALIZATION config KVM bool select PREEMPT_NOTIFIERS + select KVM_COMMON select HAVE_KVM_VCPU_ASYNC_IOCTL select KVM_VFIO select IRQ_BYPASS_MANAGER diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig index 1fd76aee3b71..55f81377d260 100644 --- a/arch/riscv/kvm/Kconfig +++ b/arch/riscv/kvm/Kconfig @@ -24,6 +24,7 @@ config KVM select HAVE_KVM_IRQ_ROUTING select HAVE_KVM_MSI select HAVE_KVM_VCPU_ASYNC_IOCTL + select KVM_COMMON select KVM_GENERIC_DIRTYLOG_READ_PROTECT select KVM_GENERIC_HARDWARE_ENABLING select KVM_MMIO diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index bb6d90351119..f89bedbe63bd 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -25,6 +25,7 @@ config KVM select HAVE_KVM_VCPU_ASYNC_IOCTL select KVM_ASYNC_PF select KVM_ASYNC_PF_SYNC + select KVM_COMMON select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQ_ROUTING select HAVE_KVM_INVALID_WAKEUPS diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index b07247b0b958..c8e62a371d24 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -24,6 +24,7 @@ config KVM depends on HIGH_RES_TIMERS depends on X86_LOCAL_APIC select PREEMPT_NOTIFIERS + select KVM_COMMON select KVM_GENERIC_MMU_NOTIFIER select HAVE_KVM_IRQCHIP select HAVE_KVM_PFNCACHE diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 6793211a0b64..cce5c03ecc92 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -3,6 +3,9 @@ config HAVE_KVM bool + +config KVM_COMMON + bool select EVENTFD config HAVE_KVM_PFNCACHE
CONFIG_HAVE_KVM is currently used by some architectures to either enabled the KVM config proper, or to enable host-side code that is not part of the KVM module. However, the "select" statement in virt/kvm/Kconfig corresponds to a third meaning, namely to enable common Kconfigs required by all architectures that support KVM. These three meanings can be replaced respectively by an architecture-specific Kconfig, by IS_ENABLED(CONFIG_KVM), or by a new Kconfig symbol that is in turn selected by the architecture-specific "config KVM". Start by introducing such a new Kconfig symbol, CONFIG_KVM_COMMON. Unlike CONFIG_HAVE_KVM, it is selected by CONFIG_KVM, not by architecture code. Fixes: 8132d887a702 ("KVM: remove CONFIG_HAVE_KVM_EVENTFD", 2023-12-08) Cc: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/arm64/kvm/Kconfig | 1 + arch/loongarch/kvm/Kconfig | 1 + arch/mips/kvm/Kconfig | 1 + arch/powerpc/kvm/Kconfig | 1 + arch/riscv/kvm/Kconfig | 1 + arch/s390/kvm/Kconfig | 1 + arch/x86/kvm/Kconfig | 1 + virt/kvm/Kconfig | 3 +++ 8 files changed, 10 insertions(+)