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KVM: ppc: Use a read lock around MMU operations, and release it on error

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gfn_to_page() and kvm_release_page_clean() are called from other contexts with
mmap_sem locked only for reading.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Hollis Blanchard 2008-05-21 18:22:54 -05:00 committed by Avi Kivity
parent 52435b7c7a
commit 905fa4b9d6
1 changed files with 3 additions and 2 deletions
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5
arch/powerpc/kvm/44x_tlb.c
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@ -142,18 +142,19 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid,
stlbe = &vcpu->arch.shadow_tlb[victim];
/* Get reference to new page. */
down_write(&current->mm->mmap_sem);
down_read(&current->mm->mmap_sem);
new_page = gfn_to_page(vcpu->kvm, gfn);
if (is_error_page(new_page)) {
printk(KERN_ERR "Couldn't get guest page!\n");
kvm_release_page_clean(new_page);
up_read(&current->mm->mmap_sem);
return;
}
hpaddr = page_to_phys(new_page);
/* Drop reference to old page. */
kvmppc_44x_shadow_release(vcpu, victim);
up_write(&current->mm->mmap_sem);
up_read(&current->mm->mmap_sem);
vcpu->arch.shadow_pages[victim] = new_page;