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Commit 1b0973bd authored by Avi Kivity's avatar Avi Kivity Committed by Linus Torvalds
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[PATCH] KVM: MMU: Use the guest pdptrs instead of mapping cr3 in pae mode 



This lets us not write protect a partial page, and is anyway what a real
processor does.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 17ac10ad

drivers/kvm/kvm_main.c

+2 −0
Original line number Diff line number Diff line
@@ -1491,6 +1491,8 @@ static int kvm_dev_ioctl_set_sregs(struct kvm *kvm, struct kvm_sregs *sregs) 


	mmu_reset_needed |= vcpu->cr4 != sregs->cr4;

	kvm_arch_ops->set_cr4(vcpu, sregs->cr4);

	if (!is_long_mode(vcpu) && is_pae(vcpu))

		load_pdptrs(vcpu, vcpu->cr3);



	if (mmu_reset_needed)

		kvm_mmu_reset_context(vcpu);

drivers/kvm/paging_tmpl.h

+18 −10
Original line number Diff line number Diff line
@@ -67,18 +67,28 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 
	hpa_t hpa;

	struct kvm_memory_slot *slot;

	pt_element_t *ptep;

	pt_element_t root;



	walker->level = vcpu->mmu.root_level;

	walker->table_gfn = (vcpu->cr3 & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

	walker->table = NULL;

	root = vcpu->cr3;

#if PTTYPE == 64

	if (!is_long_mode(vcpu)) {

		walker->ptep = &vcpu->pdptrs[(addr >> 30) & 3];

		root = *walker->ptep;

		if (!(root & PT_PRESENT_MASK))

			return;

		--walker->level;

	}

#endif

	walker->table_gfn = (root & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

	slot = gfn_to_memslot(vcpu->kvm, walker->table_gfn);

	hpa = safe_gpa_to_hpa(vcpu, vcpu->cr3 & PT64_BASE_ADDR_MASK);

	hpa = safe_gpa_to_hpa(vcpu, root & PT64_BASE_ADDR_MASK);

	walker->table = kmap_atomic(pfn_to_page(hpa >> PAGE_SHIFT), KM_USER0);



	ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||

	       (vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) == 0);



	walker->table = (pt_element_t *)( (unsigned long)walker->table |

		(unsigned long)(vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) );

	walker->inherited_ar = PT_USER_MASK | PT_WRITABLE_MASK;



	for (;;) {
@@ -89,10 +99,7 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 
		ASSERT(((unsigned long)walker->table & PAGE_MASK) ==

		       ((unsigned long)ptep & PAGE_MASK));



		/* Don't set accessed bit on PAE PDPTRs */

		if (vcpu->mmu.root_level != 3 || walker->level != 3)

			if ((*ptep & (PT_PRESENT_MASK | PT_ACCESSED_MASK))

			    == PT_PRESENT_MASK)

		if (is_present_pte(*ptep) && !(*ptep &  PT_ACCESSED_MASK))

			*ptep |= PT_ACCESSED_MASK;



		if (!is_present_pte(*ptep) ||
@@ -116,6 +123,7 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 


static void FNAME(release_walker)(struct guest_walker *walker)

{

	if (walker->table)

		kunmap_atomic(walker->table, KM_USER0);

}