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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	npiggin@gmail.com, Alexey Kardashevskiy <aik@ozlabs.ru>
Subject: [PATCH v4 16/22] powerpc/kvm/book3s: Avoid using rmap to protect parallel page table update.
Date: Tue,  5 May 2020 12:47:23 +0530	[thread overview]
Message-ID: <20200505071729.54912-17-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20200505071729.54912-1-aneesh.kumar@linux.ibm.com>

We now depend on kvm->mmu_lock

Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/kvm/book3s_64_vio_hv.c | 38 +++++++----------------------
 1 file changed, 9 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index acc3ce570be7..167029e57c8f 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -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;
 		}
@@ -607,10 +589,8 @@ 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);
-
-	arch_spin_unlock(&kvm->mmu_lock.rlock.raw_lock);
+	if (!prereg)
+		arch_spin_unlock(&kvm->mmu_lock.rlock.raw_lock);
 	return ret;
 }
 
-- 
2.26.2


  parent reply	other threads:[~2020-05-05  7:59 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05  7:17 [PATCH v4 00/22] Avoid IPI while updating page table entries Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 01/22] powerpc/pkeys: Avoid using lockless page table walk Aneesh Kumar K.V
2020-05-13  8:49   ` Michael Ellerman
2020-05-05  7:17 ` [PATCH v4 02/22] powerpc/pkeys: Check vma before returning key fault error to the user Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 03/22] powerpc/mm/hash64: use _PAGE_PTE when checking for pte_present Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 04/22] powerpc/hash64: Restrict page table lookup using init_mm with __flush_hash_table_range Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 05/22] powerpc/book3s64/hash: Use the pte_t address from the caller Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 06/22] powerpc/mce: Don't reload pte val in addr_to_pfn Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 07/22] powerpc/perf/callchain: Use __get_user_pages_fast in read_user_stack_slow Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 08/22] powerpc/kvm/book3s: switch from raw_spin_*lock to arch_spin_lock Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 09/22] powerpc/kvm/book3s: Add helper to walk partition scoped linux page table Aneesh Kumar K.V
2020-05-28  1:43   ` Paul Mackerras
2020-05-28  6:01     ` Aneesh Kumar K.V
2020-05-28  7:25       ` Paul Mackerras
2020-05-05  7:17 ` [PATCH v4 10/22] powerpc/kvm/nested: Add helper to walk nested shadow " Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 11/22] powerpc/kvm/book3s: Use kvm helpers to walk shadow or secondary table Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 12/22] powerpc/kvm/book3s: Add helper for host page table walk Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 13/22] powerpc/kvm/book3s: Use find_kvm_host_pte in page fault handler Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 14/22] powerpc/kvm/book3s: Use find_kvm_host_pte in h_enter Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 15/22] powerpc/kvm/book3s: use find_kvm_host_pte in pute_tce functions Aneesh Kumar K.V
2020-05-05  7:17 ` Aneesh Kumar K.V [this message]
2020-05-05  7:17 ` [PATCH v4 17/22] powerpc/kvm/book3s: use find_kvm_host_pte in kvmppc_book3s_instantiate_page Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 18/22] powerpc/kvm/book3s: Use find_kvm_host_pte in kvmppc_get_hpa Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 19/22] powerpc/kvm/book3s: Use pte_present instead of opencoding _PAGE_PRESENT check Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 20/22] powerpc/mm/book3s64: Avoid sending IPI on clearing PMD Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 21/22] mm: change pmdp_huge_get_and_clear_full take vm_area_struct as arg Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 22/22] powerpc/mm/book3s64: Fix MADV_DONTNEED and parallel page fault race Aneesh Kumar K.V

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