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

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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: Sean Christopherson <seanjc@google.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20250123144627.312456-2-imbrenda@linux.ibm.com
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20250123144627.312456-2-imbrenda@linux.ibm.com>
This commit is contained in:
Sean Christopherson 2025-01-23 15:46:13 +01:00 • committed by Claudio Imbrenda
parent 4514eda4c1
commit 66119f8ce1
1 changed files with 9 additions and 1 deletions
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10
virt/kvm/kvm_main.c
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@ -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);