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[PATCH v3 10/15] KVM: Add kvm_map_gfn_range
From: |
Chao Peng |
Subject: |
[PATCH v3 10/15] KVM: Add kvm_map_gfn_range |
Date: |
Tue, 21 Dec 2021 23:11:20 +0800 |
This new function establishes the mapping in KVM page tables for a
given gfn range. It can be used in the memory fallocate callback for
memfd based memory to establish the mapping for KVM secondary MMU when
the pages are allocated in the memory backend.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
arch/x86/kvm/mmu/mmu.c | 47 ++++++++++++++++++++++++++++++++++++++++
include/linux/kvm_host.h | 2 ++
virt/kvm/kvm_main.c | 5 +++++
3 files changed, 54 insertions(+)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2da19356679d..a7006e1ac2d2 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1781,6 +1781,53 @@ static __always_inline bool kvm_handle_gfn_range(struct
kvm *kvm,
return ret;
}
+bool kvm_map_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+ struct kvm_vcpu *vcpu;
+ kvm_pfn_t pfn;
+ gfn_t gfn;
+ int idx;
+ bool ret = true;
+
+ /* Need vcpu context for kvm_mmu_do_page_fault. */
+ vcpu = kvm_get_vcpu(kvm, 0);
+ if (mutex_lock_killable(&vcpu->mutex))
+ return false;
+
+ vcpu_load(vcpu);
+ idx = srcu_read_lock(&kvm->srcu);
+
+ kvm_mmu_reload(vcpu);
+
+ gfn = range->start;
+ while (gfn < range->end) {
+ if (signal_pending(current)) {
+ ret = false;
+ break;
+ }
+
+ if (need_resched())
+ cond_resched();
+
+ pfn = kvm_mmu_do_page_fault(vcpu, gfn << PAGE_SHIFT,
+ PFERR_WRITE_MASK | PFERR_USER_MASK,
+ false);
+ if (is_error_noslot_pfn(pfn) || kvm->vm_bugged) {
+ ret = false;
+ break;
+ }
+
+ gfn++;
+ }
+
+ srcu_read_unlock(&kvm->srcu, idx);
+ vcpu_put(vcpu);
+
+ mutex_unlock(&vcpu->mutex);
+
+ return ret;
+}
+
bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
{
bool flush = false;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d9573305e273..9c02fb53b8ab 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -237,6 +237,8 @@ struct kvm_gfn_range {
pte_t pte;
bool may_block;
};
+
+bool kvm_map_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d84cb867b686..b9855b2fdaae 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -456,6 +456,11 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);
#if defined(CONFIG_MEMFD_OPS) ||\
(defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER))
+bool __weak kvm_map_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+ return false;
+}
+
typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
--
2.17.1
- [PATCH v3 03/15] mm/memfd: Introduce MEMFD_OPS, (continued)
- [PATCH v3 03/15] mm/memfd: Introduce MEMFD_OPS, Chao Peng, 2021/12/21
- [PATCH v3 04/15] KVM: Extend the memslot to support fd-based private memory, Chao Peng, 2021/12/21
- [PATCH v3 05/15] KVM: Implement fd-based memory using MEMFD_OPS interfaces, Chao Peng, 2021/12/21
- [PATCH v3 06/15] KVM: Refactor hva based memory invalidation code, Chao Peng, 2021/12/21
- [PATCH v3 07/15] KVM: Special handling for fd-based memory invalidation, Chao Peng, 2021/12/21
- [PATCH v3 08/15] KVM: Split out common memory invalidation code, Chao Peng, 2021/12/21
- [PATCH v3 09/15] KVM: Implement fd-based memory invalidation, Chao Peng, 2021/12/21
- [PATCH v3 12/15] KVM: Add KVM_EXIT_MEMORY_ERROR exit, Chao Peng, 2021/12/21
- [PATCH v3 13/15] KVM: Handle page fault for private memory, Chao Peng, 2021/12/21
- [PATCH v3 14/15] KVM: Use kvm_userspace_memory_region_ext, Chao Peng, 2021/12/21
- [PATCH v3 10/15] KVM: Add kvm_map_gfn_range,
Chao Peng <=
- [PATCH v3 15/15] KVM: Register/unregister private memory slot to memfd, Chao Peng, 2021/12/21
- [PATCH v3 11/15] KVM: Implement fd-based memory fallocation, Chao Peng, 2021/12/21
- Re: [PATCH v3 00/15] KVM: mm: fd-based approach for supporting KVM guest private memory, Sean Christopherson, 2021/12/21