[3/11] KVM: Add spte's point in the struct kvm_mmu_page

Message ID 20190104085405.40356-4-Tianyu.Lan@microsoft.com
State New
Headers show
Series
  • X86/KVM/Hyper-V: Add HV ept tlb range list flush support in KVM
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Commit Message

Tianyu Lan Jan. 4, 2019, 8:53 a.m.
From: Lan Tianyu <Tianyu.Lan@microsoft.com>

It's necessary to check whether mmu page is last or large page when add
mmu page into flush list. "spte" is needed for such check and so add
spte point in the struct kvm_mmu_page.

Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/mmu.c              | 5 +++++
 arch/x86/kvm/paging_tmpl.h      | 2 ++
 3 files changed, 8 insertions(+)

Comments

Paolo Bonzini Jan. 7, 2019, 4:34 p.m. | #1
On 04/01/19 09:53, lantianyu1986@gmail.com wrote:
> @@ -332,6 +332,7 @@ struct kvm_mmu_page {
>  	int root_count;          /* Currently serving as active root */
>  	unsigned int unsync_children;
>  	struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
> +	u64 *sptep;

Is this really needed?  Can we put the "last" flag in the struct instead
as a bool?  In fact, if you do

	u16 unsync_children;
	bool unsync;
	bool last_level;

the struct does not grow at all. :)

(I'm not sure where "large" is tested using the sptep field, even though
it is in the commit message).

Paolo

>  	/* The page is obsolete if mmu_valid_gen != kvm->arch.mmu_valid_gen.  */
>  	unsigned long mmu_valid_gen;

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4660ce90de7f..78d2a6714c3b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -332,6 +332,7 @@  struct kvm_mmu_page {
 	int root_count;          /* Currently serving as active root */
 	unsigned int unsync_children;
 	struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
+	u64 *sptep;
 
 	/* The page is obsolete if mmu_valid_gen != kvm->arch.mmu_valid_gen.  */
 	unsigned long mmu_valid_gen;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ce770b446238..068694fa2371 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3160,6 +3160,7 @@  static int __direct_map(struct kvm_vcpu *vcpu, int write, int map_writable,
 			pseudo_gfn = base_addr >> PAGE_SHIFT;
 			sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
 					      iterator.level - 1, 1, ACC_ALL);
+			sp->sptep = iterator.sptep;
 
 			link_shadow_page(vcpu, iterator.sptep, sp);
 		}
@@ -3588,6 +3589,7 @@  static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
 		sp = kvm_mmu_get_page(vcpu, 0, 0,
 				vcpu->arch.mmu->shadow_root_level, 1, ACC_ALL);
 		++sp->root_count;
+		sp->sptep = NULL;
 		spin_unlock(&vcpu->kvm->mmu_lock);
 		vcpu->arch.mmu->root_hpa = __pa(sp->spt);
 	} else if (vcpu->arch.mmu->shadow_root_level == PT32E_ROOT_LEVEL) {
@@ -3604,6 +3606,7 @@  static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
 					i << 30, PT32_ROOT_LEVEL, 1, ACC_ALL);
 			root = __pa(sp->spt);
 			++sp->root_count;
+			sp->sptep = NULL;
 			spin_unlock(&vcpu->kvm->mmu_lock);
 			vcpu->arch.mmu->pae_root[i] = root | PT_PRESENT_MASK;
 		}
@@ -3644,6 +3647,7 @@  static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 				vcpu->arch.mmu->shadow_root_level, 0, ACC_ALL);
 		root = __pa(sp->spt);
 		++sp->root_count;
+		sp->sptep = NULL;
 		spin_unlock(&vcpu->kvm->mmu_lock);
 		vcpu->arch.mmu->root_hpa = root;
 		return 0;
@@ -3681,6 +3685,7 @@  static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 				      0, ACC_ALL);
 		root = __pa(sp->spt);
 		++sp->root_count;
+		sp->sptep = NULL;
 		spin_unlock(&vcpu->kvm->mmu_lock);
 
 		vcpu->arch.mmu->pae_root[i] = root | pm_mask;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 6bdca39829bc..833e8855bbc9 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -633,6 +633,7 @@  static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 			table_gfn = gw->table_gfn[it.level - 2];
 			sp = kvm_mmu_get_page(vcpu, table_gfn, addr, it.level-1,
 					      false, access);
+			sp->sptep = it.sptep;
 		}
 
 		/*
@@ -663,6 +664,7 @@  static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 
 		sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
 				      true, direct_access);
+		sp->sptep = it.sptep;
 		link_shadow_page(vcpu, it.sptep, sp);
 	}