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Commit 64d83126 authored by Christoffer Dall's avatar Christoffer Dall
Browse files

KVM: Introduce gfn_to_hva_memslot_prot 



To support read-only memory regions on arm and arm64, we have a need to
resolve a gfn to an hva given a pointer to a memslot to avoid looping
through the memslots twice and to reuse the hva error checking of
gfn_to_hva_prot(), add a new gfn_to_hva_memslot_prot() function and
refactor gfn_to_hva_prot() to use this function.

Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 7b46268d

include/linux/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -528,6 +528,8 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn); 
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);

unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable);

unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot, gfn_t gfn);

unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot, gfn_t gfn,

				      bool *writable);

void kvm_release_page_clean(struct page *page);

void kvm_release_page_dirty(struct page *page);

void kvm_set_page_accessed(struct page *page);

virt/kvm/kvm_main.c

+9 −2
Original line number Diff line number Diff line
@@ -1076,9 +1076,9 @@ EXPORT_SYMBOL_GPL(gfn_to_hva); 
 * If writable is set to false, the hva returned by this function is only

 * allowed to be read.

 */

unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)

unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,

				      gfn_t gfn, bool *writable)

{

	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);

	unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);



	if (!kvm_is_error_hva(hva) && writable)
@@ -1087,6 +1087,13 @@ unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable) 
	return hva;

}



unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)

{

	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);



	return gfn_to_hva_memslot_prot(slot, gfn, writable);

}



static int kvm_read_hva(void *data, void __user *hva, int len)

{

	return __copy_from_user(data, hva, len);