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KVM: MMU: Switch to mmu spinlock

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Convert the synchronization of the shadow handling to a separate mmu_lock
spinlock.

Also guard fetch() by mmap_sem in read-mode to protect against alias
and memslot changes.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Marcelo Tosatti
2007-12-20 19:18:26 -05:00
committed by Avi Kivity
parent d7824fff89
commit aaee2c94f7
5 changed files with 35 additions and 31 deletions
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10
arch/x86/kvm/paging_tmpl.h
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@@ -387,7 +387,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
*/
r = FNAME(walk_addr)(&walker, vcpu, addr, write_fault, user_fault,
fetch_fault);
up_read(&current->mm->mmap_sem);
/*
* The page is not mapped by the guest. Let the guest handle it.
@@ -396,12 +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);
return 0;
}
page = gfn_to_page(vcpu->kvm, walker.gfn);
mutex_lock(&vcpu->kvm->lock);
spin_lock(&vcpu->kvm->mmu_lock);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
&write_pt, page);
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,
@@ -414,13 +414,15 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
* mmio: emulate if accessible, otherwise its a guest fault.
*/
if (shadow_pte && is_io_pte(*shadow_pte)) {
mutex_unlock(&vcpu->kvm->lock);
spin_unlock(&vcpu->kvm->mmu_lock);
up_read(&current->mm->mmap_sem);
return 1;
}
++vcpu->stat.pf_fixed;
kvm_mmu_audit(vcpu, "post page fault (fixed)");
mutex_unlock(&vcpu->kvm->lock);
spin_unlock(&vcpu->kvm->mmu_lock);
up_read(&current->mm->mmap_sem);
return write_pt;
}