KVM: remove the usage of the mmap_sem for the protection of the memory slots.

[safe/jmp/linux-2.6] / arch / x86 / kvm / paging_tmpl.h

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 03ba860..2009c6e 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -91,7 +91,10 @@ static bool FNAME(cmpxchg_gpte)(struct kvm *kvm,
        pt_element_t *table;
        struct page *page;
 
+       down_read(&current->mm->mmap_sem);
        page = gfn_to_page(kvm, table_gfn);
+       up_read(&current->mm->mmap_sem);
+
        table = kmap_atomic(page, KM_USER0);
 
        ret = CMPXCHG(&table[index], orig_pte, new_pte);
@@ -378,7 +381,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
        if (r)
                return r;
 
-       down_read(&current->mm->mmap_sem);
+       down_read(&vcpu->kvm->slots_lock);
        /*
         * Look up the shadow pte for the faulting address.
         */
@@ -392,11 +395,13 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
                pgprintk("%s: guest page fault\n", __FUNCTION__);
                inject_page_fault(vcpu, addr, walker.error_code);
                vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
-               up_read(&current->mm->mmap_sem);
+               up_read(&vcpu->kvm->slots_lock);
                return 0;
        }
 
+       down_read(&current->mm->mmap_sem);
        page = gfn_to_page(vcpu->kvm, walker.gfn);
+       up_read(&current->mm->mmap_sem);
 
        spin_lock(&vcpu->kvm->mmu_lock);
        kvm_mmu_free_some_pages(vcpu);
@@ -413,14 +418,14 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
         */
        if (shadow_pte && is_io_pte(*shadow_pte)) {
                spin_unlock(&vcpu->kvm->mmu_lock);
-               up_read(&current->mm->mmap_sem);
+               up_read(&vcpu->kvm->slots_lock);
                return 1;
        }
 
        ++vcpu->stat.pf_fixed;
        kvm_mmu_audit(vcpu, "post page fault (fixed)");
        spin_unlock(&vcpu->kvm->mmu_lock);
-       up_read(&current->mm->mmap_sem);
+       up_read(&vcpu->kvm->slots_lock);
 
        return write_pt;
 }