KVM: guest_memfd: MMAP and related fixes

[PATCH v2 04/13] KVM: Explicitly mark KVM_GUEST_MEMFD as depending on KVM_GENERIC_MMU_NOTIFIER

Posted by Sean Christopherson 2 months, 2 weeks ago

Add KVM_GENERIC_MMU_NOTIFIER as a dependency for selecting KVM_GUEST_MEMFD,
as guest_memfd relies on kvm_mmu_invalidate_{begin,end}(), which are
defined if and only if the generic mmu_notifier implementation is enabled.

The missing dependency is currently benign as s390 is the only KVM arch
that doesn't utilize the generic mmu_notifier infrastructure, and s390
doesn't currently support guest_memfd.

Fixes: a7800aa80ea4 ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/kvm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 1b7d5be0b6c4..a01cc5743137 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -113,6 +113,7 @@ config KVM_GENERIC_MEMORY_ATTRIBUTES
        bool
 
 config KVM_GUEST_MEMFD
+       depends on KVM_GENERIC_MMU_NOTIFIER
        select XARRAY_MULTI
        bool
 
-- 
2.51.0.618.g983fd99d29-goog

Re: [PATCH v2 04/13] KVM: Explicitly mark KVM_GUEST_MEMFD as depending on KVM_GENERIC_MMU_NOTIFIER

Posted by David Hildenbrand 2 months, 1 week ago

On 04.10.25 01:25, Sean Christopherson wrote:
> Add KVM_GENERIC_MMU_NOTIFIER as a dependency for selecting KVM_GUEST_MEMFD,
> as guest_memfd relies on kvm_mmu_invalidate_{begin,end}(), which are
> defined if and only if the generic mmu_notifier implementation is enabled.
> 
> The missing dependency is currently benign as s390 is the only KVM arch
> that doesn't utilize the generic mmu_notifier infrastructure, and s390
> doesn't currently support guest_memfd.
> 
> Fixes: a7800aa80ea4 ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory")
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Cheers

David / dhildenb