kvm: replace __KVM_HAVE_READONLY_MEM with Kconfig symbol

KVM uses __KVM_HAVE_* symbols in the architecture-dependent uapi/asm/kvm.h to mask
unused definitions in include/uapi/linux/kvm.h.  __KVM_HAVE_READONLY_MEM however
was nothing but a misguided attempt to define KVM_CAP_READONLY_MEM only on
architectures where KVM_CHECK_EXTENSION(KVM_CAP_READONLY_MEM) could possibly
return nonzero.  This however does not make sense, and it prevented userspace
from supporting this architecture-independent feature without recompilation.

Therefore, these days __KVM_HAVE_READONLY_MEM does not mask anything and
is only used in virt/kvm/kvm_main.c.  Userspace does not need to test it
and there should be no need for it to exist.  Remove it and replace it
with a Kconfig symbol within Linux source code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

12 files changed, 9 insertions, 8 deletions

diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 75809c8dc2f0..9c1040dad4eb 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -39,7 +39,6 @@
 
 #define __KVM_HAVE_GUEST_DEBUG
 #define __KVM_HAVE_IRQ_LINE
-#define __KVM_HAVE_READONLY_MEM
 #define __KVM_HAVE_VCPU_EVENTS
 
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 6c3c8ca73e7f..114626b816f7 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -36,6 +36,7 @@ menuconfig KVM
 	select HAVE_KVM_IRQ_ROUTING
 	select IRQ_BYPASS_MANAGER
 	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
diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
index 923d0bd38294..109785922cf9 100644
--- a/arch/loongarch/include/uapi/asm/kvm.h
+++ b/arch/loongarch/include/uapi/asm/kvm.h
@@ -14,8 +14,6 @@
  * Some parts derived from the x86 version of this file.
  */
 
-#define __KVM_HAVE_READONLY_MEM
-
 #define KVM_COALESCED_MMIO_PAGE_OFFSET	1
 #define KVM_DIRTY_LOG_PAGE_OFFSET	64
 
diff --git a/arch/loongarch/kvm/Kconfig b/arch/loongarch/kvm/Kconfig
index 61f7e33b1f95..0768b45422a3 100644
--- a/arch/loongarch/kvm/Kconfig
+++ b/arch/loongarch/kvm/Kconfig
@@ -28,6 +28,7 @@ config KVM
 	select KVM_GENERIC_HARDWARE_ENABLING
 	select KVM_GENERIC_MMU_NOTIFIER
 	select KVM_MMIO
+	select HAVE_KVM_READONLY_MEM
 	select KVM_XFER_TO_GUEST_WORK
 	help
 	  Support hosting virtualized guest machines using
diff --git a/arch/mips/include/uapi/asm/kvm.h b/arch/mips/include/uapi/asm/kvm.h
index edcf717c4327..9673dc9cb315 100644
--- a/arch/mips/include/uapi/asm/kvm.h
+++ b/arch/mips/include/uapi/asm/kvm.h
@@ -20,8 +20,6 @@
  * Some parts derived from the x86 version of this file.
  */
 
-#define __KVM_HAVE_READONLY_MEM
-
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
 /*
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 18e7a17d5115..8474bf9c689e 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -26,6 +26,7 @@ config KVM
 	select KVM_MMIO
 	select KVM_GENERIC_MMU_NOTIFIER
 	select KVM_GENERIC_HARDWARE_ENABLING
+	select HAVE_KVM_READONLY_MEM
 	help
 	  Support for hosting Guest kernels.
 
diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 7499e88a947c..fdf4ba066131 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -16,7 +16,6 @@
 #include <asm/ptrace.h>
 
 #define __KVM_HAVE_IRQ_LINE
-#define __KVM_HAVE_READONLY_MEM
 
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index d490db943858..26d1727f0550 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 HAVE_KVM_READONLY_MEM
 	select KVM_COMMON
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_GENERIC_HARDWARE_ENABLING
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index bf68e56fd484..c5e682ee7726 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -51,7 +51,6 @@
 #define __KVM_HAVE_DEBUGREGS
 #define __KVM_HAVE_XSAVE
 #define __KVM_HAVE_XCRS
-#define __KVM_HAVE_READONLY_MEM
 
 /* Architectural interrupt line count. */
 #define KVM_NR_INTERRUPTS 256
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 87e3da7b0439..5895aee5dfef 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -32,6 +32,7 @@ config KVM
 	select IRQ_BYPASS_MANAGER
 	select HAVE_KVM_IRQ_BYPASS
 	select HAVE_KVM_IRQ_ROUTING
+	select HAVE_KVM_READONLY_MEM
 	select KVM_ASYNC_PF
 	select USER_RETURN_NOTIFIER
 	select KVM_MMIO
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 184dab4ee871..a11e9c80fac9 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -55,6 +55,9 @@ config KVM_ASYNC_PF_SYNC
 config HAVE_KVM_MSI
        bool
 
+config HAVE_KVM_READONLY_MEM
+       bool
+
 config HAVE_KVM_CPU_RELAX_INTERCEPT
        bool
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 10bfc88a69f7..ff588677beb7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1614,7 +1614,7 @@ static int check_memory_region_flags(struct kvm *kvm,
 	if (mem->flags & KVM_MEM_GUEST_MEMFD)
 		valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
 
-#ifdef __KVM_HAVE_READONLY_MEM
+#ifdef CONFIG_HAVE_KVM_READONLY_MEM
 	valid_flags |= KVM_MEM_READONLY;
 #endif