Commit 3ff8df14 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

powerpc/kvm/book3s: Avoid using rmap to protect parallel page table update. 



We now depend on kvm->mmu_lock

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-17-aneesh.kumar@linux.ibm.com
parent 7769a339

arch/powerpc/kvm/book3s_64_vio_hv.c

+9 −29
Original line number Diff line number Diff line
@@ -74,8 +74,8 @@ struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm, 
EXPORT_SYMBOL_GPL(kvmppc_find_table);



#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

static long kvmppc_rm_tce_to_ua(struct kvm *kvm, unsigned long tce,

		unsigned long *ua, unsigned long **prmap)

static long kvmppc_rm_tce_to_ua(struct kvm *kvm,

				unsigned long tce, unsigned long *ua)

{

	unsigned long gfn = tce >> PAGE_SHIFT;

	struct kvm_memory_slot *memslot;
@@ -87,9 +87,6 @@ static long kvmppc_rm_tce_to_ua(struct kvm *kvm, unsigned long tce, 
	*ua = __gfn_to_hva_memslot(memslot, gfn) |

		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));



	if (prmap)

		*prmap = &memslot->arch.rmap[gfn - memslot->base_gfn];



	return 0;

}
@@ -116,7 +113,7 @@ static long kvmppc_rm_tce_validate(struct kvmppc_spapr_tce_table *stt, 
	if (iommu_tce_check_gpa(stt->page_shift, gpa))

		return H_PARAMETER;



	if (kvmppc_rm_tce_to_ua(stt->kvm, tce, &ua, NULL))

	if (kvmppc_rm_tce_to_ua(stt->kvm, tce, &ua))

		return H_TOO_HARD;



	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
@@ -411,7 +408,7 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, 
		return ret;



	dir = iommu_tce_direction(tce);

	if ((dir != DMA_NONE) && kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL))

	if ((dir != DMA_NONE) && kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua))

		return H_PARAMETER;



	entry = ioba >> stt->page_shift;
@@ -488,7 +485,6 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
	struct kvmppc_spapr_tce_table *stt;

	long i, ret = H_SUCCESS;

	unsigned long tces, entry, ua = 0;

	unsigned long *rmap = NULL;

	unsigned long mmu_seq;

	bool prereg = false;

	struct kvmppc_spapr_tce_iommu_table *stit;
@@ -530,7 +526,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		 */

		struct mm_iommu_table_group_mem_t *mem;



		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce_list, &ua, NULL))

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce_list, &ua))

			return H_TOO_HARD;



		mem = mm_iommu_lookup_rm(vcpu->kvm->mm, ua, IOMMU_PAGE_SIZE_4K);
@@ -546,23 +542,9 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		 * We do not require memory to be preregistered in this case

		 * so lock rmap and do __find_linux_pte_or_hugepte().

		 */

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce_list, &ua, &rmap))

			return H_TOO_HARD;



		rmap = (void *) vmalloc_to_phys(rmap);

		if (WARN_ON_ONCE_RM(!rmap))

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce_list, &ua))

			return H_TOO_HARD;



		/*

		 * Synchronize with the MMU notifier callbacks in

		 * book3s_64_mmu_hv.c (kvm_unmap_hva_range_hv etc.).

		 * While we have the rmap lock, code running on other CPUs

		 * cannot finish unmapping the host real page that backs

		 * this guest real page, so we are OK to access the host

		 * real page.

		 */

		lock_rmap(rmap);



		arch_spin_lock(&kvm->mmu_lock.rlock.raw_lock);

		if (kvmppc_rm_ua_to_hpa(vcpu, mmu_seq, ua, &tces)) {

			ret = H_TOO_HARD;
@@ -582,7 +564,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);



		ua = 0;

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL)) {

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua)) {

			ret = H_PARAMETER;

			goto invalidate_exit;

		}
@@ -607,9 +589,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		iommu_tce_kill_rm(stit->tbl, entry, npages);



unlock_exit:

	if (rmap)

		unlock_rmap(rmap);



	if (!prereg)

		arch_spin_unlock(&kvm->mmu_lock.rlock.raw_lock);

	return ret;

}