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Subject[PATCH 09/25] KVM: ppc: kvmppc_44x_shadow_release() does not require mmap_sem to be locked
Date
From: Hollis Blanchard <hollisb@us.ibm.com>

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>
---
arch/powerpc/kvm/44x_tlb.c | 8 +-------
1 files changed, 1 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/kvm/44x_tlb.c b/arch/powerpc/kvm/44x_tlb.c
index 3594bbd..7b11fd7 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;
}

--
1.6.0.1


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