diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a46c7bf1f902..a28479629488 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3142,7 +3142,7 @@ int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map, struct kvm_follow_pfn kfp = { .slot = gfn_to_memslot(vcpu->kvm, gfn), .gfn = gfn, - .flags = FOLL_WRITE, + .flags = writable ? FOLL_WRITE : 0, .refcounted_page = &map->pinned_page, .pin = true, };
When creating a memory map for read, don't request a writable pfn from the primary MMU. While creating read-only mappings can be theoretically slower, as they don't play nice with fast GUP due to the need to break CoW before mapping the underlying PFN, practically speaking, creating a mapping isn't a super hot path, and getting a writable mapping for reading is weird and confusing. Signed-off-by: Sean Christopherson <seanjc@google.com> --- virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)