Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 905fa4b9 authored by Hollis Blanchard's avatar Hollis Blanchard Committed by Avi Kivity
Browse files

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



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

Signed-off-by: default avatarHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 52435b7c

arch/powerpc/kvm/44x_tlb.c

+3 −2
Original line number Diff line number Diff line
@@ -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;