| Date | Thu, 01 Jul 2010 10:44:43 -0700 | From | Greg KH <> | Subject | [193/200] KVM: MMU: Dont read pdptrs with mmu spinlock held in mmu_alloc_roots |
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2.6.34-stable review patch. If anyone has any objections, please let me know.
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From: Avi Kivity <avi@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@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@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)
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