[PATCH 3/33] KVM: MMU: Load the pae pdptrs on cr3 change like the processor does

Avi Kivity
2007-01-04T15:52:05Z

In pae mode, a load of cr3 loads the four third-level page table entries
in addition to cr3 itself.

Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>

Index: linux-2.6/drivers/kvm/kvm_main.c
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm_main.c
+++ linux-2.6/drivers/kvm/kvm_main.c
@@ -298,14 +298,17 @@ static void inject_gp(struct kvm_vcpu *v
kvm_arch_ops->inject_gp(vcpu, 0);
}

-static int pdptrs_have_reserved_bits_set(struct kvm_vcpu *vcpu,
- unsigned long cr3)
+/*
+ * Load the pae pdptrs. Return true is they are all valid.
+ */
+static int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
{
gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT;
- unsigned offset = (cr3 & (PAGE_SIZE-1)) >> 5;
+ unsigned offset = ((cr3 & (PAGE_SIZE-1)) >> 5) << 2;
int i;
u64 pdpte;
u64 *pdpt;
+ int ret;
struct kvm_memory_slot *memslot;

spin_lock(&vcpu->kvm->lock);
@@ -313,16 +316,23 @@ static int pdptrs_have_reserved_bits_set
/* FIXME: !memslot - emulate? 0xff? */
pdpt = kmap_atomic(gfn_to_page(memslot, pdpt_gfn), KM_USER0);

+ ret = 1;
for (i = 0; i < 4; ++i) {
pdpte = pdpt[offset + i];
- if ((pdpte & 1) && (pdpte & 0xfffffff0000001e6ull))
- break;
+ if ((pdpte & 1) && (pdpte & 0xfffffff0000001e6ull)) {
+ ret = 0;
+ goto out;
+ }
}

+ for (i = 0; i < 4; ++i)
+ vcpu->pdptrs[i] = pdpt[offset + i];
+
+out:
kunmap_atomic(pdpt, KM_USER0);
spin_unlock(&vcpu->kvm->lock);

- return i != 4;
+ return ret;
}

void set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
@@ -368,8 +378,7 @@ void set_cr0(struct kvm_vcpu *vcpu, unsi
}
} else
#endif
- if (is_pae(vcpu) &&
- pdptrs_have_reserved_bits_set(vcpu, vcpu->cr3)) {
+ if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->cr3)) {
printk(KERN_DEBUG "set_cr0: #GP, pdptrs "
"reserved bits\n");
inject_gp(vcpu);
@@ -411,7 +420,7 @@ void set_cr4(struct kvm_vcpu *vcpu, unsi
return;
}
} else if (is_paging(vcpu) && !is_pae(vcpu) && (cr4 & CR4_PAE_MASK)
- && pdptrs_have_reserved_bits_set(vcpu, vcpu->cr3)) {
+ && !load_pdptrs(vcpu, vcpu->cr3)) {
printk(KERN_DEBUG "set_cr4: #GP, pdptrs reserved bits\n");
inject_gp(vcpu);
}
@@ -443,7 +452,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsi
return;
}
if (is_paging(vcpu) && is_pae(vcpu) &&
- pdptrs_have_reserved_bits_set(vcpu, cr3)) {
+ !load_pdptrs(vcpu, cr3)) {
printk(KERN_DEBUG "set_cr3: #GP, pdptrs "
"reserved bits\n");
inject_gp(vcpu);
Index: linux-2.6/drivers/kvm/kvm.h
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm.h
+++ linux-2.6/drivers/kvm/kvm.h
@@ -185,6 +185,7 @@ struct kvm_vcpu {
unsigned long cr3;
unsigned long cr4;
unsigned long cr8;
+ u64 pdptrs[4]; /* pae */
u64 shadow_efer;
u64 apic_base;
int nmsrs;