Commit 66119f8c authored by Sean Christopherson's avatar Sean Christopherson Committed by Claudio Imbrenda
Browse files

KVM: Do not restrict the size of KVM-internal memory regions 

Exempt KVM-internal memslots from the KVM_MEM_MAX_NR_PAGES restriction, as
the limit on the number of pages exists purely to play nice with dirty
bitmap operations, which use 32-bit values to index the bitmaps, and dirty
logging isn't supported for KVM-internal memslots.

Link: https://lore.kernel.org/all/20240802205003.353672-6-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarChristoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20250123144627.312456-2-imbrenda@linux.ibm.com


Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20250123144627.312456-2-imbrenda@linux.ibm.com>
parent 4514eda4

virt/kvm/kvm_main.c

+9 −1
Original line number Diff line number Diff line
@@ -1971,7 +1971,15 @@ static int kvm_set_memory_region(struct kvm *kvm, 
		return -EINVAL;

	if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)

		return -EINVAL;

	if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)



	/*

	 * The size of userspace-defined memory regions is restricted in order

	 * to play nice with dirty bitmap operations, which are indexed with an

	 * "unsigned int".  KVM's internal memory regions don't support dirty

	 * logging, and so are exempt.

	 */

	if (id < KVM_USER_MEM_SLOTS &&

	    (mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)

		return -EINVAL;



	slots = __kvm_memslots(kvm, as_id);