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>

1 files changed, 2 insertions, 11 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 6fc342194dda..c563283cb982 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1204,8 +1204,6 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
 
         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 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
         /* mmio */
         if (is_error_page(page)) {
                 kvm_release_page_clean(page);
-                up_read(&vcpu->kvm->slots_lock);
                 return 1;
         }
 
@@ -1228,7 +1225,6 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
                          PT32E_ROOT_LEVEL);
         spin_unlock(&vcpu->kvm->mmu_lock);
 
-        up_read(&vcpu->kvm->slots_lock);
 
         return r;
 }
@@ -1376,9 +1372,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
                 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 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
         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 @@ int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
         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 @@ static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
         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 kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
         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 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
 out:
         *ret = buffer.processed;
         up_read(&current->mm->mmap_sem);
-        up_read(&vcpu->kvm->slots_lock);
         return r;
 }