[patch 01/10] KVM: MMU: split mmu_set_spte

Marcelo Tosatti
2008-09-18T21:49:40Z

[-- Attachment #1: mmu-set-spte --]
[-- Type: text/plain, Size: 4394 bytes --]

Split the spte entry creation code into a new set_spte function.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm/arch/x86/kvm/mmu.c
===================================================================
--- kvm.orig/arch/x86/kvm/mmu.c
+++ kvm/arch/x86/kvm/mmu.c
@@ -1148,44 +1148,13 @@ struct page *gva_to_page(struct kvm_vcpu
return page;
}

-static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
- unsigned pt_access, unsigned pte_access,
- int user_fault, int write_fault, int dirty,
- int *ptwrite, int largepage, gfn_t gfn,
- pfn_t pfn, bool speculative)
+static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
+ unsigned pte_access, int user_fault,
+ int write_fault, int dirty, int largepage,
+ gfn_t gfn, pfn_t pfn, bool speculative)
{
u64 spte;
- int was_rmapped = 0;
- int was_writeble = is_writeble_pte(*shadow_pte);
-
- pgprintk("%s: spte %llx access %x write_fault %d"
- " user_fault %d gfn %lx\n",
- __func__, *shadow_pte, pt_access,
- write_fault, user_fault, gfn);
-
- if (is_rmap_pte(*shadow_pte)) {
- /*
- * If we overwrite a PTE page pointer with a 2MB PMD, unlink
- * the parent of the now unreachable PTE.
- */
- if (largepage && !is_large_pte(*shadow_pte)) {
- struct kvm_mmu_page *child;
- u64 pte = *shadow_pte;
-
- child = page_header(pte & PT64_BASE_ADDR_MASK);
- mmu_page_remove_parent_pte(child, shadow_pte);
- } else if (pfn != spte_to_pfn(*shadow_pte)) {
- pgprintk("hfn old %lx new %lx\n",
- spte_to_pfn(*shadow_pte), pfn);
- rmap_remove(vcpu->kvm, shadow_pte);
- } else {
- if (largepage)
- was_rmapped = is_large_pte(*shadow_pte);
- else
- was_rmapped = 1;
- }
- }
-
+ int ret = 0;
/*
* We don't set the accessed bit, since we sometimes want to see
* whether the guest actually used the pte (in order to detect
@@ -1218,26 +1187,70 @@ static void mmu_set_spte(struct kvm_vcpu
(largepage && has_wrprotected_page(vcpu->kvm, gfn))) {
pgprintk("%s: found shadow page for %lx, marking ro\n",
__func__, gfn);
+ ret = 1;
pte_access &= ~ACC_WRITE_MASK;
if (is_writeble_pte(spte)) {
spte &= ~PT_WRITABLE_MASK;
kvm_x86_ops->tlb_flush(vcpu);
}
- if (write_fault)
- *ptwrite = 1;
}
}

if (pte_access & ACC_WRITE_MASK)
mark_page_dirty(vcpu->kvm, gfn);

- pgprintk("%s: setting spte %llx\n", __func__, spte);
- pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
- (spte&PT_PAGE_SIZE_MASK)? "2MB" : "4kB",
- (spte&PT_WRITABLE_MASK)?"RW":"R", gfn, spte, shadow_pte);
set_shadow_pte(shadow_pte, spte);
- if (!was_rmapped && (spte & PT_PAGE_SIZE_MASK)
- && (spte & PT_PRESENT_MASK))
+ return ret;
+}
+
+
+static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
+ unsigned pt_access, unsigned pte_access,
+ int user_fault, int write_fault, int dirty,
+ int *ptwrite, int largepage, gfn_t gfn,
+ pfn_t pfn, bool speculative)
+{
+ int was_rmapped = 0;
+ int was_writeble = is_writeble_pte(*shadow_pte);
+
+ pgprintk("%s: spte %llx access %x write_fault %d"
+ " user_fault %d gfn %lx\n",
+ __func__, *shadow_pte, pt_access,
+ write_fault, user_fault, gfn);
+
+ if (is_rmap_pte(*shadow_pte)) {
+ /*
+ * If we overwrite a PTE page pointer with a 2MB PMD, unlink
+ * the parent of the now unreachable PTE.
+ */
+ if (largepage && !is_large_pte(*shadow_pte)) {
+ struct kvm_mmu_page *child;
+ u64 pte = *shadow_pte;
+
+ child = page_header(pte & PT64_BASE_ADDR_MASK);
+ mmu_page_remove_parent_pte(child, shadow_pte);
+ } else if (pfn != spte_to_pfn(*shadow_pte)) {
+ pgprintk("hfn old %lx new %lx\n",
+ spte_to_pfn(*shadow_pte), pfn);
+ rmap_remove(vcpu->kvm, shadow_pte);
+ } else {
+ if (largepage)
+ was_rmapped = is_large_pte(*shadow_pte);
+ else
+ was_rmapped = 1;
+ }
+ }
+ if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
+ dirty, largepage, gfn, pfn, speculative))
+ if (write_fault)
+ *ptwrite = 1;
+
+ pgprintk("%s: setting spte %llx\n", __func__, *shadow_pte);
+ pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
+ is_large_pte(*shadow_pte)? "2MB" : "4kB",
+ is_present_pte(*shadow_pte)?"RW":"R", gfn,
+ *shadow_pte, shadow_pte);
+ if (!was_rmapped && is_large_pte(*shadow_pte))
++vcpu->kvm->stat.lpages;

page_header_update_slot(vcpu->kvm, shadow_pte, gfn);

--