commit 3200f405a1e8e06c8634f11d33614455baa4e6be
author Marcelo Tosatti <marcelo@kvack.org> Sat Mar 29 20:17:59 2008 -0300
committer Avi Kivity <avi@qumranet.com> Sun Apr 27 12:00:52 2008 +0300
tree 806116d2495dd7fd93b5c0db98a72fe4fa854787
parent 25c5f225beda4fbea878ed8b6203ab4ecc7de2d1

KVM: MMU: unify slots_lock usage

Unify slots_lock acquision around vcpu_run(). This is simpler and less
error-prone.

Also fix some callsites that were not grabbing the lock properly.

[avi: drop slots_lock while in guest mode to avoid holding the lock
      for indefinite periods]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/mmu.c

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 6fc3421..c563283 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1204,8 +1204,6 @@
 
 	struct page *page;
 
-	down_read(&vcpu->kvm->slots_lock);
-
 	down_read(&current->mm->mmap_sem);
 	if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
 		gfn &= ~(KVM_PAGES_PER_HPAGE-1);
@@ -1218,7 +1216,6 @@
 	/* mmio */
 	if (is_error_page(page)) {
 		kvm_release_page_clean(page);
-		up_read(&vcpu->kvm->slots_lock);
 		return 1;
 	}
 
@@ -1228,7 +1225,6 @@
 			 PT32E_ROOT_LEVEL);
 	spin_unlock(&vcpu->kvm->mmu_lock);
 
-	up_read(&vcpu->kvm->slots_lock);
 
 	return r;
 }
@@ -1376,9 +1372,9 @@
 		largepage = 1;
 	}
 	page = gfn_to_page(vcpu->kvm, gfn);
+	up_read(&current->mm->mmap_sem);
 	if (is_error_page(page)) {
 		kvm_release_page_clean(page);
-		up_read(&current->mm->mmap_sem);
 		return 1;
 	}
 	spin_lock(&vcpu->kvm->mmu_lock);
@@ -1386,7 +1382,6 @@
 	r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
 			 largepage, gfn, page, TDP_ROOT_LEVEL);
 	spin_unlock(&vcpu->kvm->mmu_lock);
-	up_read(&current->mm->mmap_sem);
 
 	return r;
 }
@@ -1808,9 +1803,7 @@
 	gpa_t gpa;
 	int r;
 
-	down_read(&vcpu->kvm->slots_lock);
 	gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
-	up_read(&vcpu->kvm->slots_lock);
 
 	spin_lock(&vcpu->kvm->mmu_lock);
 	r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
@@ -2063,7 +2056,7 @@
 	if (r)
 		return r;
 
-	if (!__emulator_write_phys(vcpu, addr, &value, bytes))
+	if (!emulator_write_phys(vcpu, addr, &value, bytes))
 		return -EFAULT;
 
 	return 1;
@@ -2127,7 +2120,6 @@
 	int r;
 	struct kvm_pv_mmu_op_buffer buffer;
 
-	down_read(&vcpu->kvm->slots_lock);
 	down_read(&current->mm->mmap_sem);
 
 	buffer.ptr = buffer.buf;
@@ -2150,7 +2142,6 @@
 out:
 	*ret = buffer.processed;
 	up_read(&current->mm->mmap_sem);
-	up_read(&vcpu->kvm->slots_lock);
 	return r;
 }