KVM: introduce CONFIG_KVM_COMMON

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, CONFIG_KVM's "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, and it brings in all dependencies of common
KVM code.  In particular, INTERVAL_TREE was missing in loongarch
and riscv, so that is another thing that is fixed.

Fixes: 8132d887a702 ("KVM: remove CONFIG_HAVE_KVM_EVENTFD", 2023-12-08)
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/44907c6b-c5bd-4e4a-a921-e4d3825539d8@infradead.org/
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 6793211a0b64..ace72be98fb2 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -3,7 +3,12 @@
 
 config HAVE_KVM
        bool
+
+config KVM_COMMON
+       bool
        select EVENTFD
+       select INTERVAL_TREE
+       select PREEMPT_NOTIFIERS
 
 config HAVE_KVM_PFNCACHE
        bool