KVM: Simply gfn_to_page()

Mapping a guest page to a host page is a common operation.  Currently,
one has first to find the memory slot where the page belongs (gfn_to_memslot),
then locate the page itself (gfn_to_page()).

This is clumsy, and also won't work well with memory aliases.  So simplify
gfn_to_page() not to require memory slot translation first, and instead do it
internally.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 376800a..8bdb9ca 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -390,13 +390,11 @@ static void rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
 {
 	struct kvm *kvm = vcpu->kvm;
 	struct page *page;
-	struct kvm_memory_slot *slot;
 	struct kvm_rmap_desc *desc;
 	u64 *spte;
 
-	slot = gfn_to_memslot(kvm, gfn);
-	BUG_ON(!slot);
-	page = gfn_to_page(slot, gfn);
+	page = gfn_to_page(kvm, gfn);
+	BUG_ON(!page);
 
 	while (page_private(page)) {
 		if (!(page_private(page) & 1))
@@ -711,14 +709,12 @@ hpa_t safe_gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa)
 
 hpa_t gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa)
 {
-	struct kvm_memory_slot *slot;
 	struct page *page;
 
 	ASSERT((gpa & HPA_ERR_MASK) == 0);
-	slot = gfn_to_memslot(vcpu->kvm, gpa >> PAGE_SHIFT);
-	if (!slot)
+	page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+	if (!page)
 		return gpa | HPA_ERR_MASK;
-	page = gfn_to_page(slot, gpa >> PAGE_SHIFT);
 	return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT)
 		| (gpa & (PAGE_SIZE-1));
 }