KVM: ppc: kvmppc_44x_shadow_release() does not require mmap_sem to be locked

And it gets in the way of get_user_pages_fast().

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 1 insertions, 7 deletions

diff --git a/arch/powerpc/kvm/44x_tlb.c b/arch/powerpc/kvm/44x_tlb.c
index 3594bbd1f618..7b11fd7be542 100644
--- a/arch/powerpc/kvm/44x_tlb.c
+++ b/arch/powerpc/kvm/44x_tlb.c
@@ -110,7 +110,6 @@ static int kvmppc_44x_tlbe_is_writable(struct tlbe *tlbe)
         return tlbe->word2 & (PPC44x_TLB_SW|PPC44x_TLB_UW);
 }
 
-/* Must be called with mmap_sem locked for writing. */
 static void kvmppc_44x_shadow_release(struct kvm_vcpu *vcpu,
                                       unsigned int index)
 {
@@ -150,17 +149,16 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid,
         /* Get reference to new page. */
         down_read(&current->mm->mmap_sem);
         new_page = gfn_to_page(vcpu->kvm, gfn);
+        up_read(&current->mm->mmap_sem);
         if (is_error_page(new_page)) {
                 printk(KERN_ERR "Couldn't get guest page for gfn %lx!\n", gfn);
                 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_read(&current->mm->mmap_sem);
 
         vcpu->arch.shadow_pages[victim] = new_page;
 
@@ -194,7 +192,6 @@ void kvmppc_mmu_invalidate(struct kvm_vcpu *vcpu, gva_t eaddr,
         int i;
 
         /* XXX Replace loop with fancy data structures. */
-        down_write(&current->mm->mmap_sem);
         for (i = 0; i <= tlb_44x_hwater; i++) {
                 struct tlbe *stlbe = &vcpu->arch.shadow_tlb[i];
                 unsigned int tid;
@@ -219,7 +216,6 @@ void kvmppc_mmu_invalidate(struct kvm_vcpu *vcpu, gva_t eaddr,
                                 stlbe->tid, stlbe->word0, stlbe->word1,
                                 stlbe->word2, handler);
         }
-        up_write(&current->mm->mmap_sem);
 }
 
 /* Invalidate all mappings on the privilege switch after PID has been changed.
@@ -231,7 +227,6 @@ void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode)
 
         if (vcpu->arch.swap_pid) {
                 /* XXX Replace loop with fancy data structures. */
-                down_write(&current->mm->mmap_sem);
                 for (i = 0; i <= tlb_44x_hwater; i++) {
                         struct tlbe *stlbe = &vcpu->arch.shadow_tlb[i];
 
@@ -243,7 +238,6 @@ void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode)
                                     stlbe->tid, stlbe->word0, stlbe->word1,
                                     stlbe->word2, handler);
                 }
-                up_write(&current->mm->mmap_sem);
                 vcpu->arch.swap_pid = 0;
         }