Re: [RFC 6/8]KVM: introduce kvm_mmu_zap_pagetbl

From: Avi Kivity
Date: Mon Jul 23 2007 - 07:16:37 EST


Shaohua Li wrote:
add a routine to zap all shadow pgtble for a gfn. If kvm supports SMP,
the API should zap pgtble for all vcpus, but kvm shadow page table
really should be per-vm, instead of per-vcpu.


kvm shadow page tables _are_ per-vm. Current kvm.git even makes that more explicit where functions that remove stuff (like rmap_remove()) don't require a vcpu.


Index: linux/drivers/kvm/kvm.h
===================================================================
--- linux.orig/drivers/kvm/kvm.h 2007-07-20 14:19:15.000000000 +0800
+++ linux/drivers/kvm/kvm.h 2007-07-20 14:26:10.000000000 +0800
@@ -621,6 +621,7 @@ int kvm_mmu_unprotect_page_virt(struct k
void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);
void kvm_mmu_unload(struct kvm_vcpu *vcpu);
+void kvm_mmu_zap_pagetbl(struct kvm_vcpu *vcpu, u64 gfn);
int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run);
Index: linux/drivers/kvm/mmu.c
===================================================================
--- linux.orig/drivers/kvm/mmu.c 2007-07-20 14:25:25.000000000 +0800
+++ linux/drivers/kvm/mmu.c 2007-07-20 14:26:10.000000000 +0800
@@ -1324,6 +1324,34 @@ void kvm_mmu_zap_all(struct kvm_vcpu *vc
init_kvm_mmu(vcpu);
}
+/* FIXME: this should zap all vcpu's shadow pgtbl for gfn */
+void kvm_mmu_zap_pagetbl(struct kvm_vcpu *vcpu, u64 gfn)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_rmap_desc *desc;
+ struct page *page;
+ u64 *spte;
+
+ page = gfn_to_page(kvm, gfn);
+ BUG_ON(!page);
+
+ while (page_private(page)) {
+ if (!(page_private(page) & 1))
+ spte = (u64 *)page_private(page);
+ else {
+ desc = (struct kvm_rmap_desc *)(page_private(page) & ~1ul);
+ spte = desc->shadow_ptes[0];
+ }
+ BUG_ON(!spte);
+ BUG_ON((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT
+ != page_to_pfn(page));
+ BUG_ON(!(*spte & PT_PRESENT_MASK));
+ rmap_remove(vcpu, spte);
+ *spte = 0;
+ }
+ kvm_flush_remote_tlbs(vcpu->kvm);
+}
+

Suggest kvm_mmu_unmap_page() as a name for this.


--
error compiling committee.c: too many arguments to function

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