Commit 70295a479da6 for kernel
commit 70295a479da684905c18d96656d781823f418ec2
Author: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed Feb 11 19:06:31 2026 +0100
KVM: always define KVM_CAP_SYNC_MMU
KVM_CAP_SYNC_MMU is provided by KVM's MMU notifiers, which are now always
available. Move the definition from individual architectures to common
code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index fc5736839edd..6f85e1b321dd 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -1396,7 +1396,10 @@ or its flags may be modified, but it may not be resized.
Memory for the region is taken starting at the address denoted by the
field userspace_addr, which must point at user addressable memory for
the entire memory slot size. Any object may back this memory, including
-anonymous memory, ordinary files, and hugetlbfs.
+anonymous memory, ordinary files, and hugetlbfs. Changes in the backing
+of the memory region are automatically reflected into the guest.
+For example, an mmap() that affects the region will be made visible
+immediately. Another example is madvise(MADV_DROP).
On architectures that support a form of address tagging, userspace_addr must
be an untagged address.
@@ -1412,11 +1415,6 @@ use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it,
to make a new slot read-only. In this case, writes to this memory will be
posted to userspace as KVM_EXIT_MMIO exits.
-When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of
-the memory region are automatically reflected into the guest. For example, an
-mmap() that affects the region will be made visible immediately. Another
-example is madvise(MADV_DROP).
-
For TDX guest, deleting/moving memory region loses guest memory contents.
Read only region isn't supported. Only as-id 0 is supported.
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 29f0326f7e00..410ffd41fd73 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -358,7 +358,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
break;
case KVM_CAP_IOEVENTFD:
case KVM_CAP_USER_MEMORY:
- case KVM_CAP_SYNC_MMU:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
case KVM_CAP_ONE_REG:
case KVM_CAP_ARM_PSCI:
diff --git a/arch/loongarch/kvm/vm.c b/arch/loongarch/kvm/vm.c
index 63fd40530aa9..5282158b8122 100644
--- a/arch/loongarch/kvm/vm.c
+++ b/arch/loongarch/kvm/vm.c
@@ -118,7 +118,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_ONE_REG:
case KVM_CAP_ENABLE_CAP:
case KVM_CAP_READONLY_MEM:
- case KVM_CAP_SYNC_MMU:
case KVM_CAP_IMMEDIATE_EXIT:
case KVM_CAP_IOEVENTFD:
case KVM_CAP_MP_STATE:
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index b0fb92fda4d4..29d9f630edfb 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1035,7 +1035,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_ONE_REG:
case KVM_CAP_ENABLE_CAP:
case KVM_CAP_READONLY_MEM:
- case KVM_CAP_SYNC_MMU:
case KVM_CAP_IMMEDIATE_EXIT:
r = 1;
break;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 3da40ea8c562..00302399fc37 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -623,11 +623,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = !!(hv_enabled && kvmppc_hv_ops->enable_nested &&
!kvmppc_hv_ops->enable_nested(NULL));
break;
-#endif
- case KVM_CAP_SYNC_MMU:
- r = 1;
- break;
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
case KVM_CAP_PPC_HTAB_FD:
r = hv_enabled;
break;
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index 7cbd2340c190..58bce57dc55b 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -181,7 +181,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
break;
case KVM_CAP_IOEVENTFD:
case KVM_CAP_USER_MEMORY:
- case KVM_CAP_SYNC_MMU:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
case KVM_CAP_ONE_REG:
case KVM_CAP_READONLY_MEM:
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 7a175d86cef0..bc7d6fa66eaf 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -601,7 +601,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
switch (ext) {
case KVM_CAP_S390_PSW:
case KVM_CAP_S390_GMAP:
- case KVM_CAP_SYNC_MMU:
#ifdef CONFIG_KVM_S390_UCONTROL
case KVM_CAP_S390_UCONTROL:
#endif
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3fb64905d190..a03530795707 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4805,7 +4805,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
#endif
case KVM_CAP_NOP_IO_DELAY:
case KVM_CAP_MP_STATE:
- case KVM_CAP_SYNC_MMU:
case KVM_CAP_USER_NMI:
case KVM_CAP_IRQ_INJECT_STATUS:
case KVM_CAP_IOEVENTFD:
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 29ee01747347..1bc1da66b4b0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4870,6 +4870,7 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
{
switch (arg) {
+ case KVM_CAP_SYNC_MMU:
case KVM_CAP_USER_MEMORY:
case KVM_CAP_USER_MEMORY2:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: