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authorAndrea Arcangeli <andrea@qumranet.com>2008-07-25 16:24:52 +0200
committerAvi Kivity <avi@qumranet.com>2008-07-29 12:33:53 +0300
commite930bffe95e1e886a1ede80726ea38df5838d067 (patch)
treed39227c3de8e7d4a70737c78693f6d7f458066af /arch/x86
parent604b38ac0369bd50fcbb33344aa5553c071009f7 (diff)
KVM: Synchronize guest physical memory map to host virtual memory map
Synchronize changes to host virtual addresses which are part of a KVM memory slot to the KVM shadow mmu. This allows pte operations like swapping, page migration, and madvise() to transparently work with KVM. Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/mmu.c100
-rw-r--r--arch/x86/kvm/paging_tmpl.h12
2 files changed, 112 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2fa231923cf..0bfe2bd305e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -653,6 +653,84 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
account_shadowed(kvm, gfn);
}
+static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
+{
+ u64 *spte;
+ int need_tlb_flush = 0;
+
+ while ((spte = rmap_next(kvm, rmapp, NULL))) {
+ BUG_ON(!(*spte & PT_PRESENT_MASK));
+ rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
+ rmap_remove(kvm, spte);
+ set_shadow_pte(spte, shadow_trap_nonpresent_pte);
+ need_tlb_flush = 1;
+ }
+ return need_tlb_flush;
+}
+
+static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
+ int (*handler)(struct kvm *kvm, unsigned long *rmapp))
+{
+ int i;
+ int retval = 0;
+
+ /*
+ * If mmap_sem isn't taken, we can look the memslots with only
+ * the mmu_lock by skipping over the slots with userspace_addr == 0.
+ */
+ for (i = 0; i < kvm->nmemslots; i++) {
+ struct kvm_memory_slot *memslot = &kvm->memslots[i];
+ unsigned long start = memslot->userspace_addr;
+ unsigned long end;
+
+ /* mmu_lock protects userspace_addr */
+ if (!start)
+ continue;
+
+ end = start + (memslot->npages << PAGE_SHIFT);
+ if (hva >= start && hva < end) {
+ gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
+ retval |= handler(kvm, &memslot->rmap[gfn_offset]);
+ retval |= handler(kvm,
+ &memslot->lpage_info[
+ gfn_offset /
+ KVM_PAGES_PER_HPAGE].rmap_pde);
+ }
+ }
+
+ return retval;
+}
+
+int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
+{
+ return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
+}
+
+static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
+{
+ u64 *spte;
+ int young = 0;
+
+ spte = rmap_next(kvm, rmapp, NULL);
+ while (spte) {
+ int _young;
+ u64 _spte = *spte;
+ BUG_ON(!(_spte & PT_PRESENT_MASK));
+ _young = _spte & PT_ACCESSED_MASK;
+ if (_young) {
+ young = 1;
+ clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
+ }
+ spte = rmap_next(kvm, rmapp, spte);
+ }
+ return young;
+}
+
+int kvm_age_hva(struct kvm *kvm, unsigned long hva)
+{
+ return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
+}
+
#ifdef MMU_DEBUG
static int is_empty_shadow_page(u64 *spt)
{
@@ -1203,6 +1281,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
int r;
int largepage = 0;
pfn_t pfn;
+ unsigned long mmu_seq;
down_read(&current->mm->mmap_sem);
if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
@@ -1210,6 +1289,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
largepage = 1;
}
+ mmu_seq = vcpu->kvm->mmu_notifier_seq;
+ /* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);
@@ -1220,6 +1301,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
}
spin_lock(&vcpu->kvm->mmu_lock);
+ if (mmu_notifier_retry(vcpu, mmu_seq))
+ goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, v, write, largepage, gfn, pfn,
PT32E_ROOT_LEVEL);
@@ -1227,6 +1310,11 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
return r;
+
+out_unlock:
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ kvm_release_pfn_clean(pfn);
+ return 0;
}
@@ -1345,6 +1433,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
int r;
int largepage = 0;
gfn_t gfn = gpa >> PAGE_SHIFT;
+ unsigned long mmu_seq;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
@@ -1358,6 +1447,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
gfn &= ~(KVM_PAGES_PER_HPAGE-1);
largepage = 1;
}
+ mmu_seq = vcpu->kvm->mmu_notifier_seq;
+ /* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);
if (is_error_pfn(pfn)) {
@@ -1365,12 +1456,19 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
return 1;
}
spin_lock(&vcpu->kvm->mmu_lock);
+ if (mmu_notifier_retry(vcpu, mmu_seq))
+ goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
largepage, gfn, pfn, kvm_x86_ops->get_tdp_level());
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
+
+out_unlock:
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ kvm_release_pfn_clean(pfn);
+ return 0;
}
static void nonpaging_free(struct kvm_vcpu *vcpu)
@@ -1670,6 +1768,8 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
gfn &= ~(KVM_PAGES_PER_HPAGE-1);
vcpu->arch.update_pte.largepage = 1;
}
+ vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
+ /* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 4d918220bae..f72ac1fa35f 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -263,6 +263,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
pfn = vcpu->arch.update_pte.pfn;
if (is_error_pfn(pfn))
return;
+ if (mmu_notifier_retry(vcpu, vcpu->arch.update_pte.mmu_seq))
+ return;
kvm_get_pfn(pfn);
mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
gpte & PT_DIRTY_MASK, NULL, largepage, gpte_to_gfn(gpte),
@@ -380,6 +382,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
int r;
pfn_t pfn;
int largepage = 0;
+ unsigned long mmu_seq;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
kvm_mmu_audit(vcpu, "pre page fault");
@@ -413,6 +416,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
largepage = 1;
}
}
+ mmu_seq = vcpu->kvm->mmu_notifier_seq;
+ /* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
up_read(&current->mm->mmap_sem);
@@ -424,6 +429,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
}
spin_lock(&vcpu->kvm->mmu_lock);
+ if (mmu_notifier_retry(vcpu, mmu_seq))
+ goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
largepage, &write_pt, pfn);
@@ -439,6 +446,11 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
spin_unlock(&vcpu->kvm->mmu_lock);
return write_pt;
+
+out_unlock:
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ kvm_release_pfn_clean(pfn);
+ return 0;
}
static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)