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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: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
hifive-unleashed-5.1
Christoffer Dall 2014-08-19 12:15:00 +02:00
parent 7b46268d29
commit 64d831269c
2 changed files with 11 additions and 2 deletions
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2
include/linux/kvm_host.h
View File

@ -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);

11
virt/kvm/kvm_main.c
View File

@ -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);