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Commit 3da0dd43 authored by Izik Eidus's avatar Izik Eidus Committed by Avi Kivity
Browse files

KVM: add support for change_pte mmu notifiers 



this is needed for kvm if it want ksm to directly map pages into its
shadow page tables.

[marcelo: cast pfn assignment to u64]

Signed-off-by: default avatarIzik Eidus <ieidus@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 1403283a

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -796,6 +796,7 @@ asmlinkage void kvm_handle_fault_on_reboot(void); 
#define KVM_ARCH_WANT_MMU_NOTIFIER

int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);

int kvm_age_hva(struct kvm *kvm, unsigned long hva);

void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);

int cpuid_maxphyaddr(struct kvm_vcpu *vcpu);

int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);

int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu);

arch/x86/kvm/mmu.c

+53 −9
Original line number Diff line number Diff line
@@ -748,7 +748,7 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn) 
	return write_protected;

}



static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)

static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 data)

{

	u64 *spte;

	int need_tlb_flush = 0;
@@ -763,8 +763,45 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp) 
	return need_tlb_flush;

}



static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,

			  int (*handler)(struct kvm *kvm, unsigned long *rmapp))

static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 data)

{

	int need_flush = 0;

	u64 *spte, new_spte;

	pte_t *ptep = (pte_t *)data;

	pfn_t new_pfn;



	WARN_ON(pte_huge(*ptep));

	new_pfn = pte_pfn(*ptep);

	spte = rmap_next(kvm, rmapp, NULL);

	while (spte) {

		BUG_ON(!is_shadow_present_pte(*spte));

		rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);

		need_flush = 1;

		if (pte_write(*ptep)) {

			rmap_remove(kvm, spte);

			__set_spte(spte, shadow_trap_nonpresent_pte);

			spte = rmap_next(kvm, rmapp, NULL);

		} else {

			new_spte = *spte &~ (PT64_BASE_ADDR_MASK);

			new_spte |= (u64)new_pfn << PAGE_SHIFT;



			new_spte &= ~PT_WRITABLE_MASK;

			new_spte &= ~SPTE_HOST_WRITEABLE;

			if (is_writeble_pte(*spte))

				kvm_set_pfn_dirty(spte_to_pfn(*spte));

			__set_spte(spte, new_spte);

			spte = rmap_next(kvm, rmapp, spte);

		}

	}

	if (need_flush)

		kvm_flush_remote_tlbs(kvm);



	return 0;

}



static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, u64 data,

			  int (*handler)(struct kvm *kvm, unsigned long *rmapp,

					 u64 data))

{

	int i, j;

	int retval = 0;
@@ -786,13 +823,15 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, 
		if (hva >= start && hva < end) {

			gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;



			retval |= handler(kvm, &memslot->rmap[gfn_offset]);

			retval |= handler(kvm, &memslot->rmap[gfn_offset],

					  data);



			for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) {

				int idx = gfn_offset;

				idx /= KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL + j);

				retval |= handler(kvm,

					&memslot->lpage_info[j][idx].rmap_pde);

					&memslot->lpage_info[j][idx].rmap_pde,

					data);

			}

		}

	}
@@ -802,10 +841,15 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, 


int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)

{

	return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);

	return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);

}



void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)

{

	kvm_handle_hva(kvm, hva, (u64)&pte, kvm_set_pte_rmapp);

}



static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)

static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 data)

{

	u64 *spte;

	int young = 0;
@@ -841,13 +885,13 @@ static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) 
	gfn = unalias_gfn(vcpu->kvm, gfn);

	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);



	kvm_unmap_rmapp(vcpu->kvm, rmapp);

	kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);

	kvm_flush_remote_tlbs(vcpu->kvm);

}



int kvm_age_hva(struct kvm *kvm, unsigned long hva)

{

	return kvm_handle_hva(kvm, hva, kvm_age_rmapp);

	return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);

}



#ifdef MMU_DEBUG

virt/kvm/kvm_main.c

+14 −0
Original line number Diff line number Diff line
@@ -850,6 +850,19 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn, 


}



static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,

					struct mm_struct *mm,

					unsigned long address,

					pte_t pte)

{

	struct kvm *kvm = mmu_notifier_to_kvm(mn);



	spin_lock(&kvm->mmu_lock);

	kvm->mmu_notifier_seq++;

	kvm_set_spte_hva(kvm, address, pte);

	spin_unlock(&kvm->mmu_lock);

}



static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,

						    struct mm_struct *mm,

						    unsigned long start,
@@ -929,6 +942,7 @@ static const struct mmu_notifier_ops kvm_mmu_notifier_ops = { 
	.invalidate_range_start	= kvm_mmu_notifier_invalidate_range_start,

	.invalidate_range_end	= kvm_mmu_notifier_invalidate_range_end,

	.clear_flush_young	= kvm_mmu_notifier_clear_flush_young,

	.change_pte		= kvm_mmu_notifier_change_pte,

	.release		= kvm_mmu_notifier_release,

};

#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */