Prev: [198/200] KVM: SVM: Dont allow nested guest to VMMCALL into host
Next: [186/200] KVM: x86: Add callback to let modules decide over some supported cpuid bits
From: Greg KH on 1 Jul 2010 17:30
2.6.34-stable review patch. If anyone has any objections, please let me know.

------------------

From: Avi Kivity <avi(a)redhat.com>

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(a)amd.com>
Signed-off-by: Avi Kivity <avi(a)redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

(Cherry-picked from commit 8facbbff071ff2b19268d3732e31badc60471e21)
---
arch/x86/kvm/mmu.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2085,11 +2085,13 @@ static int mmu_alloc_roots(struct kvm_vc
direct = 1;
if (mmu_check_root(vcpu, root_gfn))
return 1;
+ 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;
}
@@ -2111,11 +2113,14 @@ static int mmu_alloc_roots(struct kvm_vc
root_gfn = 0;
if (mmu_check_root(vcpu, root_gfn))
return 1;
+ 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);
@@ -2479,7 +2484,9 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
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)


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: [198/200] KVM: SVM: Dont allow nested guest to VMMCALL into host
Next: [186/200] KVM: x86: Add callback to let modules decide over some supported cpuid bits