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

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@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index b65511e..8323f40 100644 (file)
--- a/drivers/kvm/kvm.h
+++ b/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;

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index f2a6b6f..4512d8c 100644 (file)
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -298,14 +298,17 @@ static void inject_gp(struct kvm_vcpu *vcpu)
        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(struct kvm_vcpu *vcpu,
        /* 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, unsigned long cr0)
                        }
                } 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, unsigned long cr4)
                        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, unsigned long cr3)
                        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);