diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-10-03 16:25:58 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2025-10-10 14:25:25 -0700 |
| commit | 44c6cb9fe9888b371e31165b2854bd0f4e2787d4 (patch) | |
| tree | 25333a75f2f488f76c79a1c4967cb724e0b2102a /include/linux | |
| parent | 9aef71c892a55e004419923ba7129abe3e58d9f1 (diff) | |
KVM: guest_memfd: Allow mmap() on guest_memfd for x86 VMs with private memory
Allow mmap() on guest_memfd instances for x86 VMs with private memory as
the need to track private vs. shared state in the guest_memfd instance is
only pertinent to INIT_SHARED. Doing mmap() on private memory isn't
terrible useful (yet!), but it's now possible, and will be desirable when
guest_memfd gains support for other VMA-based syscalls, e.g. mbind() to
set NUMA policy.
Lift the restriction now, before MMAP support is officially released, so
that KVM doesn't need to add another capability to enumerate support for
mmap() on private memory.
Fixes: 3d3a04fad25a ("KVM: Allow and advertise support for host mmap() on guest_memfd files")
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/kvm_host.h | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 19b8c4bebb9c..680ca838f018 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -729,7 +729,17 @@ static inline bool kvm_arch_has_private_mem(struct kvm *kvm) #endif #ifdef CONFIG_KVM_GUEST_MEMFD -bool kvm_arch_supports_gmem_mmap(struct kvm *kvm); +bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm); + +static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm) +{ + u64 flags = GUEST_MEMFD_FLAG_MMAP; + + if (!kvm || kvm_arch_supports_gmem_init_shared(kvm)) + flags |= GUEST_MEMFD_FLAG_INIT_SHARED; + + return flags; +} #endif #ifndef kvm_arch_has_readonly_mem |