[PATCH 06/26] KVM: Drop CONFIG_KVM_VFIO and just look at KVM+VFIO

Sean Christopherson
2023-09-16T00:35:25Z

Drop KVM's KVM_VFIO Kconfig, and instead compile in VFIO support if
and only if VFIO itself is enabled. Similar to the recent change to have
VFIO stop looking at HAVE_KVM, compiling in support for talking to VFIO
just because the architecture supports VFIO is nonsensical.

This fixes a bug where RISC-V doesn't select KVM_VFIO, i.e. would silently
fail to do connect KVM and VFIO, even though RISC-V supports VFIO. The
bug is benign as the only driver in all of Linux that actually uses the
KVM reference provided by VFIO is KVM-GT, which is x86/Intel specific.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/arm64/kvm/Kconfig | 1 -
arch/powerpc/kvm/Kconfig | 1 -
arch/s390/kvm/Kconfig | 1 -
arch/x86/kvm/Kconfig | 1 -
virt/kvm/Kconfig | 3 ---
virt/kvm/Makefile.kvm | 4 +++-
virt/kvm/vfio.h | 2 +-
7 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 83c1e09be42e..2b5c332f157d 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -28,7 +28,6 @@ menuconfig KVM
select KVM_MMIO
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_XFER_TO_GUEST_WORK
- select KVM_VFIO
select HAVE_KVM_EVENTFD
select HAVE_KVM_IRQFD
select HAVE_KVM_DIRTY_RING_ACQ_REL
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 902611954200..c4beb49c0eb2 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -22,7 +22,6 @@ config KVM
select PREEMPT_NOTIFIERS
select HAVE_KVM_EVENTFD
select HAVE_KVM_VCPU_ASYNC_IOCTL
- select KVM_VFIO
select IRQ_BYPASS_MANAGER
select HAVE_KVM_IRQ_BYPASS
select INTERVAL_TREE
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 45fdf2a9b2e3..459d536116a6 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -31,7 +31,6 @@ config KVM
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_INVALID_WAKEUPS
select HAVE_KVM_NO_POLL
- select KVM_VFIO
select INTERVAL_TREE
select MMU_NOTIFIER
help
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index ed90f148140d..0f01e5600b5f 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -45,7 +45,6 @@ config KVM
select HAVE_KVM_NO_POLL
select KVM_XFER_TO_GUEST_WORK
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
- select KVM_VFIO
select INTERVAL_TREE
select HAVE_KVM_PM_NOTIFIER if PM
select KVM_GENERIC_HARDWARE_ENABLING
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 484d0873061c..f0be3b55cea6 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -59,9 +59,6 @@ config HAVE_KVM_MSI
config HAVE_KVM_CPU_RELAX_INTERCEPT
bool

-config KVM_VFIO
- bool
-
config HAVE_KVM_INVALID_WAKEUPS
bool

diff --git a/virt/kvm/Makefile.kvm b/virt/kvm/Makefile.kvm
index 2c27d5d0c367..29373b59d89a 100644
--- a/virt/kvm/Makefile.kvm
+++ b/virt/kvm/Makefile.kvm
@@ -6,7 +6,9 @@
KVM ?= ../../../virt/kvm

kvm-y := $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/binary_stats.o
-kvm-$(CONFIG_KVM_VFIO) += $(KVM)/vfio.o
+ifdef CONFIG_VFIO
+kvm-y += $(KVM)/vfio.o
+endif
kvm-$(CONFIG_KVM_MMIO) += $(KVM)/coalesced_mmio.o
kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
kvm-$(CONFIG_HAVE_KVM_IRQ_ROUTING) += $(KVM)/irqchip.o
diff --git a/virt/kvm/vfio.h b/virt/kvm/vfio.h
index e130a4a03530..af475a323965 100644
--- a/virt/kvm/vfio.h
+++ b/virt/kvm/vfio.h
@@ -2,7 +2,7 @@
#ifndef __KVM_VFIO_H
#define __KVM_VFIO_H

-#ifdef CONFIG_KVM_VFIO
+#if IS_ENABLED(CONFIG_KVM) && IS_ENABLED(CONFIG_VFIO)
int kvm_vfio_ops_init(void);
void kvm_vfio_ops_exit(void);
#else
--
2.42.0.459.ge4e396fd5e-goog