KVM: MMU: Don't read pdptrs with mmu spinlock held in mmu_alloc_roots
On svm, kvm_read_pdptr() may require reading guest memory, which can sleep.
Push the spinlock into mmu_alloc_roots(), and only take it after we've read
the pdptr.
Tested-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 51eb6d6..de99638 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2065,11 +2065,13 @@
direct = 1;
root_gfn = 0;
}
+ spin_lock(&vcpu->kvm->mmu_lock);
sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
PT64_ROOT_LEVEL, direct,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
+ spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = root;
return 0;
}
@@ -2093,11 +2095,14 @@
direct = 1;
root_gfn = i << 30;
}
+ spin_lock(&vcpu->kvm->mmu_lock);
sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
PT32_ROOT_LEVEL, direct,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
+ spin_unlock(&vcpu->kvm->mmu_lock);
+
vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
}
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
@@ -2466,7 +2471,9 @@
goto out;
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
+ spin_unlock(&vcpu->kvm->mmu_lock);
r = mmu_alloc_roots(vcpu);
+ spin_lock(&vcpu->kvm->mmu_lock);
mmu_sync_roots(vcpu);
spin_unlock(&vcpu->kvm->mmu_lock);
if (r)