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Commit e8bc217a authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
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KVM: MMU: mode specific sync_page 



Examine guest pagetable and bring the shadow back in sync. Caller is responsible
for local TLB flush before re-entering guest mode.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 38187c83

arch/x86/kvm/mmu.c

+10 −0
Original line number Diff line number Diff line
@@ -871,6 +871,12 @@ static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu, 
		sp->spt[i] = shadow_trap_nonpresent_pte;

}



static int nonpaging_sync_page(struct kvm_vcpu *vcpu,

			       struct kvm_mmu_page *sp)

{

	return 1;

}



static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)

{

	unsigned index;
@@ -1547,6 +1553,7 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu) 
	context->gva_to_gpa = nonpaging_gva_to_gpa;

	context->free = nonpaging_free;

	context->prefetch_page = nonpaging_prefetch_page;

	context->sync_page = nonpaging_sync_page;

	context->root_level = 0;

	context->shadow_root_level = PT32E_ROOT_LEVEL;

	context->root_hpa = INVALID_PAGE;
@@ -1594,6 +1601,7 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level) 
	context->page_fault = paging64_page_fault;

	context->gva_to_gpa = paging64_gva_to_gpa;

	context->prefetch_page = paging64_prefetch_page;

	context->sync_page = paging64_sync_page;

	context->free = paging_free;

	context->root_level = level;

	context->shadow_root_level = level;
@@ -1615,6 +1623,7 @@ static int paging32_init_context(struct kvm_vcpu *vcpu) 
	context->gva_to_gpa = paging32_gva_to_gpa;

	context->free = paging_free;

	context->prefetch_page = paging32_prefetch_page;

	context->sync_page = paging32_sync_page;

	context->root_level = PT32_ROOT_LEVEL;

	context->shadow_root_level = PT32E_ROOT_LEVEL;

	context->root_hpa = INVALID_PAGE;
@@ -1634,6 +1643,7 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) 
	context->page_fault = tdp_page_fault;

	context->free = nonpaging_free;

	context->prefetch_page = nonpaging_prefetch_page;

	context->sync_page = nonpaging_sync_page;

	context->shadow_root_level = kvm_x86_ops->get_tdp_level();

	context->root_hpa = INVALID_PAGE;

arch/x86/kvm/paging_tmpl.h

+54 −0
Original line number Diff line number Diff line
@@ -507,6 +507,60 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, 
	}

}



/*

 * Using the cached information from sp->gfns is safe because:

 * - The spte has a reference to the struct page, so the pfn for a given gfn

 *   can't change unless all sptes pointing to it are nuked first.

 * - Alias changes zap the entire shadow cache.

 */

static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)

{

	int i, offset, nr_present;



	offset = nr_present = 0;



	if (PTTYPE == 32)

		offset = sp->role.quadrant << PT64_LEVEL_BITS;



	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {

		unsigned pte_access;

		pt_element_t gpte;

		gpa_t pte_gpa;

		gfn_t gfn = sp->gfns[i];



		if (!is_shadow_present_pte(sp->spt[i]))

			continue;



		pte_gpa = gfn_to_gpa(sp->gfn);

		pte_gpa += (i+offset) * sizeof(pt_element_t);



		if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,

					  sizeof(pt_element_t)))

			return -EINVAL;



		if (gpte_to_gfn(gpte) != gfn || !is_present_pte(gpte) ||

		    !(gpte & PT_ACCESSED_MASK)) {

			u64 nonpresent;



			rmap_remove(vcpu->kvm, &sp->spt[i]);

			if (is_present_pte(gpte))

				nonpresent = shadow_trap_nonpresent_pte;

			else

				nonpresent = shadow_notrap_nonpresent_pte;

			set_shadow_pte(&sp->spt[i], nonpresent);

			continue;

		}



		nr_present++;

		pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);

		set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,

			 is_dirty_pte(gpte), 0, gfn,

			 spte_to_pfn(sp->spt[i]), true);

	}



	return !nr_present;

}



#undef pt_element_t

#undef guest_walker

#undef shadow_walker

include/asm-x86/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -220,6 +220,8 @@ struct kvm_mmu { 
	gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva);

	void (*prefetch_page)(struct kvm_vcpu *vcpu,

			      struct kvm_mmu_page *page);

	int (*sync_page)(struct kvm_vcpu *vcpu,

			 struct kvm_mmu_page *sp);

	hpa_t root_hpa;

	int root_level;

	int shadow_root_level;