Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 04bae9d5 authored by Suraj Jitindar Singh's avatar Suraj Jitindar Singh Committed by Michael Ellerman
Browse files

KVM: PPC: Book3S HV: Refactor radix page fault handler 



The radix page fault handler accounts for all cases, including just
needing to insert a pte.  This breaks it up into separate functions for
the two main cases; setting rc and inserting a pte.

This allows us to make the setting of rc and inserting of a pte
generic for any pgtable, not specific to the one for this guest.

[paulus@ozlabs.org - reduced diffs from previous code]

Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 9811c78e

arch/powerpc/kvm/book3s_64_mmu_radix.c

+123 −87
Original line number Diff line number Diff line
@@ -400,8 +400,9 @@ static void kvmppc_unmap_free_pud_entry_table(struct kvm *kvm, pud_t *pud, 
 */

#define PTE_BITS_MUST_MATCH (~(_PAGE_WRITE | _PAGE_DIRTY | _PAGE_ACCESSED))



static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,

			     unsigned int level, unsigned long mmu_seq)

static int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte,

			     unsigned long gpa, unsigned int level,

			     unsigned long mmu_seq)

{

	pgd_t *pgd;

	pud_t *pud, *new_pud = NULL;
@@ -410,7 +411,7 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa, 
	int ret;



	/* Traverse the guest's 2nd-level tree, allocate new levels needed */

	pgd = kvm->arch.pgtable + pgd_index(gpa);

	pgd = pgtable + pgd_index(gpa);

	pud = NULL;

	if (pgd_present(*pgd))

		pud = pud_offset(pgd, gpa);
@@ -565,69 +566,13 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa, 
	return ret;

}



int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,

				   unsigned long ea, unsigned long dsisr)

static bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable,

				    bool writing, unsigned long gpa)

{

	struct kvm *kvm = vcpu->kvm;

	unsigned long mmu_seq;

	unsigned long gpa, gfn, hva;

	struct kvm_memory_slot *memslot;

	struct page *page = NULL;

	long ret;

	bool writing;

	bool upgrade_write = false;

	bool *upgrade_p = &upgrade_write;

	pte_t pte, *ptep;

	unsigned long pgflags;

	unsigned int shift, level;



	/* Check for unusual errors */

	if (dsisr & DSISR_UNSUPP_MMU) {

		pr_err("KVM: Got unsupported MMU fault\n");

		return -EFAULT;

	}

	if (dsisr & DSISR_BADACCESS) {

		/* Reflect to the guest as DSI */

		pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr);

		kvmppc_core_queue_data_storage(vcpu, ea, dsisr);

		return RESUME_GUEST;

	}



	/* Translate the logical address and get the page */

	gpa = vcpu->arch.fault_gpa & ~0xfffUL;

	gpa &= ~0xF000000000000000ul;

	gfn = gpa >> PAGE_SHIFT;

	if (!(dsisr & DSISR_PRTABLE_FAULT))

		gpa |= ea & 0xfff;

	memslot = gfn_to_memslot(kvm, gfn);



	/* No memslot means it's an emulated MMIO region */

	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {

		if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS |

			     DSISR_SET_RC)) {

			/*

			 * Bad address in guest page table tree, or other

			 * unusual error - reflect it to the guest as DSI.

			 */

			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);

			return RESUME_GUEST;

		}

		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,

					      dsisr & DSISR_ISSTORE);

	}



	writing = (dsisr & DSISR_ISSTORE) != 0;

	if (memslot->flags & KVM_MEM_READONLY) {

		if (writing) {

			/* give the guest a DSI */

			dsisr = DSISR_ISSTORE | DSISR_PROTFAULT;

			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);

			return RESUME_GUEST;

		}

		upgrade_p = NULL;

	}

	unsigned int shift;

	pte_t *ptep;



	if (dsisr & DSISR_SET_RC) {

	/*

	 * Need to set an R or C bit in the 2nd-level tables;

	 * since we are just helping out the hardware here,
@@ -637,24 +582,34 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, 
	if (writing)

		pgflags |= _PAGE_DIRTY;

	/*

		 * We are walking the secondary page table here. We can do this

		 * without disabling irq.

	 * We are walking the secondary (partition-scoped) page table here.

	 * We can do this without disabling irq because the Linux MM

	 * subsystem doesn't do THP splits and collapses on this tree.

	 */

		spin_lock(&kvm->mmu_lock);

		ptep = __find_linux_pte(kvm->arch.pgtable,

					gpa, NULL, &shift);

		if (ptep && pte_present(*ptep) &&

		    (!writing || pte_write(*ptep))) {

			kvmppc_radix_update_pte(kvm, ptep, 0, pgflags,

						gpa, shift);

			dsisr &= ~DSISR_SET_RC;

	ptep = __find_linux_pte(pgtable, gpa, NULL, &shift);

	if (ptep && pte_present(*ptep) && (!writing || pte_write(*ptep))) {

		kvmppc_radix_update_pte(kvm, ptep, 0, pgflags, gpa, shift);

		return true;

	}

		spin_unlock(&kvm->mmu_lock);

		if (!(dsisr & (DSISR_BAD_FAULT_64S | DSISR_NOHPTE |

			       DSISR_PROTFAULT | DSISR_SET_RC)))

			return RESUME_GUEST;

	return false;

}



static int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,

				unsigned long gpa,

				struct kvm_memory_slot *memslot,

				bool writing, bool kvm_ro,

				pte_t *inserted_pte, unsigned int *levelp)

{

	struct kvm *kvm = vcpu->kvm;

	struct page *page = NULL;

	unsigned long mmu_seq;

	unsigned long hva, gfn = gpa >> PAGE_SHIFT;

	bool upgrade_write = false;

	bool *upgrade_p = &upgrade_write;

	pte_t pte, *ptep;

	unsigned int shift, level;

	int ret;



	/* used to check for invalidations in progress */

	mmu_seq = kvm->mmu_notifier_seq;

	smp_rmb();
@@ -666,7 +621,7 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, 
	 * is that the page is writable.

	 */

	hva = gfn_to_hva_memslot(memslot, gfn);

	if (upgrade_p && __get_user_pages_fast(hva, 1, 1, &page) == 1) {

	if (!kvm_ro && __get_user_pages_fast(hva, 1, 1, &page) == 1) {

		upgrade_write = true;

	} else {

		unsigned long pfn;
@@ -724,7 +679,12 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, 
	}



	/* Allocate space in the tree and write the PTE */

	ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);

	ret = kvmppc_create_pte(kvm, kvm->arch.pgtable, pte, gpa, level,

				mmu_seq);

	if (inserted_pte)

		*inserted_pte = pte;

	if (levelp)

		*levelp = level;



	if (page) {

		if (!ret && (pte_val(pte) & _PAGE_WRITE))
@@ -732,6 +692,82 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, 
		put_page(page);

	}



	return ret;

}



int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,

				   unsigned long ea, unsigned long dsisr)

{

	struct kvm *kvm = vcpu->kvm;

	unsigned long gpa, gfn;

	struct kvm_memory_slot *memslot;

	long ret;

	bool writing = !!(dsisr & DSISR_ISSTORE);

	bool kvm_ro = false;



	/* Check for unusual errors */

	if (dsisr & DSISR_UNSUPP_MMU) {

		pr_err("KVM: Got unsupported MMU fault\n");

		return -EFAULT;

	}

	if (dsisr & DSISR_BADACCESS) {

		/* Reflect to the guest as DSI */

		pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr);

		kvmppc_core_queue_data_storage(vcpu, ea, dsisr);

		return RESUME_GUEST;

	}



	/* Translate the logical address */

	gpa = vcpu->arch.fault_gpa & ~0xfffUL;

	gpa &= ~0xF000000000000000ul;

	gfn = gpa >> PAGE_SHIFT;

	if (!(dsisr & DSISR_PRTABLE_FAULT))

		gpa |= ea & 0xfff;



	/* Get the corresponding memslot */

	memslot = gfn_to_memslot(kvm, gfn);



	/* No memslot means it's an emulated MMIO region */

	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {

		if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS |

			     DSISR_SET_RC)) {

			/*

			 * Bad address in guest page table tree, or other

			 * unusual error - reflect it to the guest as DSI.

			 */

			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);

			return RESUME_GUEST;

		}

		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea, writing);

	}



	if (memslot->flags & KVM_MEM_READONLY) {

		if (writing) {

			/* give the guest a DSI */

			kvmppc_core_queue_data_storage(vcpu, ea, DSISR_ISSTORE |

						       DSISR_PROTFAULT);

			return RESUME_GUEST;

		}

		kvm_ro = true;

	}



	/* Failed to set the reference/change bits */

	if (dsisr & DSISR_SET_RC) {

		spin_lock(&kvm->mmu_lock);

		if (kvmppc_hv_handle_set_rc(kvm, kvm->arch.pgtable,

					    writing, gpa))

			dsisr &= ~DSISR_SET_RC;

		spin_unlock(&kvm->mmu_lock);



		if (!(dsisr & (DSISR_BAD_FAULT_64S | DSISR_NOHPTE |

			       DSISR_PROTFAULT | DSISR_SET_RC)))

			return RESUME_GUEST;

	}



	/* Try to insert a pte */

	ret = kvmppc_book3s_instantiate_page(vcpu, gpa, memslot, writing,

					     kvm_ro, NULL, NULL);



	if (ret == 0 || ret == -EAGAIN)

		ret = RESUME_GUEST;

	return ret;