Re: [PATCH v9 02/24] KVM: Move architecture capability Kconfigs to header defines
From: Paolo Bonzini
Date: Mon Oct 12 2026 - 13:54:13 EST
On 9/30/26 19:34, Steffen Eiden wrote:
Historically, KVM feature opt-ins and callbacks were configured globally
via Kconfig symbols (CONFIG_HAVE_KVM_* and CONFIG_KVM_*).
Not all of them - there are many __KVM_HAVE_* symbols already. In particular now there's both KVM_MSI and __KVM_HAVE_MSI/__KVM_HAVE_MSIX (but the latter is dead, so I have sent a patch to remove it).
There are several remaining CONFIG_HAVE_KVM_ARCH_* Kconfig symbols as well. That's okay, but it should be noted in the changelog that not all symbols were fixed.
Can you at least quickly provide a v2, that changes all symbols to __KVM_HAVE_<function-name> (and when not applicable __KVM_*, for example __KVM_HAVE_READONLY_MEM)? I have already changed KVM_NO_MMIO to __KVM_NO_MMIO in kvm/queue.
Thanks,
Paolo
Replace these global Kconfig options with architecture-specific opt-in
defines in <asm/kvm_host.h> and standardize their naming by dropping the
HAVE_ prefix:
- KVM_INVALID_WAKEUPS
- KVM_MSI (formerly HAVE_KVM_MSI)
- KVM_NO_POLL (formerly HAVE_KVM_NO_POLL)
- KVM_READONLY_MEM (formerly HAVE_KVM_READONLY_MEM)
- KVM_VCPU_RUN_PID_CHANGE (formerly HAVE_KVM_VCPU_RUN_PID_CHANGE)
This allows each architecture and guest implementation to configure its
supported capabilities independently in its kvm_host header and eliminates
unnecessary fallback stubs across different KVM targets.
Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 3 +++
arch/arm64/kvm/Kconfig | 3 ---
arch/loongarch/include/asm/kvm_host.h | 2 ++
arch/loongarch/kvm/Kconfig | 2 --
arch/mips/include/asm/kvm_host.h | 1 +
arch/mips/kvm/Kconfig | 1 -
arch/powerpc/include/asm/kvm_host.h | 3 +++
arch/powerpc/kvm/Kconfig | 1 -
arch/riscv/include/asm/kvm_host.h | 2 ++
arch/riscv/kvm/Kconfig | 2 --
arch/s390/include/asm/kvm_host_s390.h | 3 +++
arch/s390/kvm/Kconfig | 2 --
arch/x86/include/asm/kvm_host.h | 3 +++
arch/x86/kvm/Kconfig | 3 ---
include/linux/kvm_host.h | 18 +++++++++++-------
virt/kvm/Kconfig | 15 ---------------
virt/kvm/kvm_main.c | 4 ++--
17 files changed, 30 insertions(+), 38 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index cd9b9d2462f9..db002e5ac9d4 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -30,6 +30,9 @@
#include <asm/vncr_mapping.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#define KVM_MSI
+#define KVM_READONLY_MEM
+#define KVM_VCPU_RUN_PID_CHANGE
#define KVM_HALT_POLL_NS_DEFAULT 500000
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 449154f9a485..7329124deb2f 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -28,12 +28,9 @@ menuconfig KVM
select KVM_VFIO
select HAVE_KVM_DIRTY_RING_ACQ_REL
select NEED_KVM_DIRTY_RING_WITH_BITMAP
- select HAVE_KVM_MSI
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_IRQ_BYPASS
- select HAVE_KVM_READONLY_MEM
- select HAVE_KVM_VCPU_RUN_PID_CHANGE
select SCHED_INFO
select GUEST_PERF_EVENTS if PERF_EVENTS
select KVM_GUEST_MEMFD
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 65d91c3ce313..4cb370a8d09b 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -26,6 +26,8 @@
#include <asm/loongarch.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#define KVM_MSI
+#define KVM_READONLY_MEM
/* Loongarch KVM register ids */
#define KVM_GET_IOC_CSR_IDX(id) ((id & KVM_CSR_IDX_MASK) >> LOONGARCH_REG_SHIFT)
diff --git a/arch/loongarch/kvm/Kconfig b/arch/loongarch/kvm/Kconfig
index 15da2d88c0c1..a427429a2b05 100644
--- a/arch/loongarch/kvm/Kconfig
+++ b/arch/loongarch/kvm/Kconfig
@@ -23,8 +23,6 @@ config KVM
select HAVE_KVM_DIRTY_RING_ACQ_REL
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_IRQCHIP
- select HAVE_KVM_MSI
- select HAVE_KVM_READONLY_MEM
select KVM_COMMON
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_GENERIC_HARDWARE_ENABLING
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index c14b10821817..8e484bb482ba 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -893,5 +893,6 @@ static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+#define KVM_READONLY_MEM
#endif /* __MIPS_KVM_HOST_H__ */
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index b1b9a1d67758..c24b872afbcb 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -24,7 +24,6 @@ config KVM
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_MMIO
select KVM_GENERIC_HARDWARE_ENABLING
- select HAVE_KVM_READONLY_MEM
help
Support for hosting Guest kernels.
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 2d139c807577..ad7c34e9b227 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -49,6 +49,9 @@
#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#ifdef CONFIG_KVM_MPIC
+#define KVM_MSI
+#endif
#define KVM_HALT_POLL_NS_DEFAULT 10000 /* 10 us */
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index b6bc2fc86dca..1fae2de8fa68 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -232,7 +232,6 @@ config KVM_MPIC
depends on KVM && PPC_E500
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQ_ROUTING
- select HAVE_KVM_MSI
help
Enable support for emulating MPIC devices inside the
host kernel, rather than relying on userspace to emulate.
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index a30600579231..23b5560e97ba 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -47,6 +47,8 @@
#define KVM_REQ_STEAL_UPDATE KVM_ARCH_REQ(6)
#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
+#define KVM_MSI
+#define KVM_READONLY_MEM
#define KVM_HAVE_MMU_RWLOCK
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index ec2cee0a39e0..3cb4f8037300 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -22,8 +22,6 @@ config KVM
depends on RISCV_SBI && MMU
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQ_ROUTING
- select HAVE_KVM_MSI
- select HAVE_KVM_READONLY_MEM
select HAVE_KVM_DIRTY_RING_ACQ_REL
select KVM_COMMON
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
diff --git a/arch/s390/include/asm/kvm_host_s390.h b/arch/s390/include/asm/kvm_host_s390.h
index 9519b8028b10..bd42c84b8b16 100644
--- a/arch/s390/include/asm/kvm_host_s390.h
+++ b/arch/s390/include/asm/kvm_host_s390.h
@@ -34,6 +34,9 @@
#define KVM_INTERNAL_MEM_SLOTS 1
+#define KVM_INVALID_WAKEUPS
+#define KVM_NO_POLL
+
#define KVM_S390_MANAGES_S390_GUEST 1
/*
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 8d3ee17a1bcb..9045ae20fd89 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -25,8 +25,6 @@ config KVM
select KVM_COMMON
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQ_ROUTING
- select HAVE_KVM_INVALID_WAKEUPS
- select HAVE_KVM_NO_POLL
select KVM_VFIO
select VIRT_XFER_TO_GUEST_WORK
select KVM_MMU_LOCKLESS_AGING
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e460073ff176..d8f6333de323 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -47,6 +47,9 @@
#define kvm_file_to_kvm_arch x86
#define __KVM_HAVE_ARCH_VCPU_DEBUGFS
+#define KVM_MSI
+#define KVM_NO_POLL
+#define KVM_READONLY_MEM
/*
* CONFIG_KVM_MAX_NR_VCPUS is defined iff CONFIG_KVM!=n, provide a dummy max if
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 538ed1e80332..294684b217bb 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -28,7 +28,6 @@ config KVM_X86
select HAVE_KVM_DIRTY_RING_ACQ_REL
select HAVE_KVM_IRQ_BYPASS
select HAVE_KVM_IRQ_ROUTING
- select HAVE_KVM_READONLY_MEM
select VHOST_TASK
select KVM_ASYNC_PF
select USER_RETURN_NOTIFIER
@@ -37,9 +36,7 @@ config KVM_X86
select PERF_EVENTS
select GUEST_PERF_EVENTS
select PERF_GUEST_MEDIATED_PMU
- select HAVE_KVM_MSI
select HAVE_KVM_CPU_RELAX_INTERCEPT
- select HAVE_KVM_NO_POLL
select VIRT_XFER_TO_GUEST_WORK
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_VFIO
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 160e3e64ec6d..a0e9cc55a6a4 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -750,7 +750,11 @@ static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
#ifndef kvm_arch_has_readonly_mem
static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm)
{
- return IS_ENABLED(CONFIG_HAVE_KVM_READONLY_MEM);
+#ifdef KVM_READONLY_MEM
+ return true;
+#else
+ return false;
+#endif
}
#endif
@@ -2486,7 +2490,7 @@ void kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
struct kvm_kernel_irq_routing_entry *new);
#endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */
-#ifdef CONFIG_HAVE_KVM_INVALID_WAKEUPS
+#ifdef KVM_INVALID_WAKEUPS
/* If we wakeup during the poll time, was it a sucessful poll? */
static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu)
{
@@ -2498,9 +2502,9 @@ static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu)
{
return true;
}
-#endif /* CONFIG_HAVE_KVM_INVALID_WAKEUPS */
+#endif /* KVM_INVALID_WAKEUPS */
-#ifdef CONFIG_HAVE_KVM_NO_POLL
+#ifdef KVM_NO_POLL
/* Callback that tells if we must not poll */
bool kvm_arch_no_poll(struct kvm_vcpu *vcpu);
#else
@@ -2508,18 +2512,18 @@ static inline bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
{
return false;
}
-#endif /* CONFIG_HAVE_KVM_NO_POLL */
+#endif /* KVM_NO_POLL */
void kvm_arch_guest_memory_reclaimed(struct kvm *kvm);
-#ifdef CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE
+#ifdef KVM_VCPU_RUN_PID_CHANGE
int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu);
#else
static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
{
return 0;
}
-#endif /* CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE */
+#endif /* KVM_VCPU_RUN_PID_CHANGE */
#ifdef CONFIG_VIRT_XFER_TO_GUEST_WORK
static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index c3c0ee253fc7..f3d7f66746c8 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -50,21 +50,12 @@ config KVM_ASYNC_PF
config KVM_ASYNC_PF_SYNC
bool
-config HAVE_KVM_MSI
- bool
-
-config HAVE_KVM_READONLY_MEM
- bool
-
config HAVE_KVM_CPU_RELAX_INTERCEPT
bool
config KVM_VFIO
bool
-config HAVE_KVM_INVALID_WAKEUPS
- bool
-
config KVM_GENERIC_DIRTYLOG_READ_PROTECT
bool
@@ -79,12 +70,6 @@ config HAVE_KVM_IRQ_BYPASS
tristate
select IRQ_BYPASS_MANAGER
-config HAVE_KVM_VCPU_RUN_PID_CHANGE
- bool
-
-config HAVE_KVM_NO_POLL
- bool
-
config VIRT_XFER_TO_GUEST_WORK
bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f62901b7e23d..cd2d752816ab 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4916,7 +4916,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
case KVM_CAP_INTERNAL_ERROR_DATA:
-#ifdef CONFIG_HAVE_KVM_MSI
+#ifdef KVM_MSI
case KVM_CAP_SIGNAL_MSI:
#endif
#ifdef CONFIG_HAVE_KVM_IRQCHIP
@@ -5306,7 +5306,7 @@ static long kvm_vm_ioctl(struct file *filp,
r = kvm_ioeventfd(kvm, &data);
break;
}
-#ifdef CONFIG_HAVE_KVM_MSI
+#ifdef KVM_MSI
case KVM_SIGNAL_MSI: {
struct kvm_msi msi;