KVM: x86/mmu: Add a helper to consolidate root sp allocation

Add a helper, mmu_alloc_root(), to consolidate the allocation of a root
shadow page, which has the same basic mechanics for all flavors of TDP
and shadow paging.

Note, __pa(sp->spt) doesn't need to be protected by mmu_lock, sp->spt
points at a kernel page.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200428023714.31923-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index fd94668c0f0f48a851f20d0af2de5369f82415ab..907625fea7b3cf8829bfa27235beffa28426f646 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3678,37 +3678,43 @@ static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
        return ret;
 }
 
-static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
+static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva,
+                           u8 level, bool direct)
 {
        struct kvm_mmu_page *sp;
+
+       spin_lock(&vcpu->kvm->mmu_lock);
+
+       if (make_mmu_pages_available(vcpu)) {
+               spin_unlock(&vcpu->kvm->mmu_lock);
+               return INVALID_PAGE;
+       }
+       sp = kvm_mmu_get_page(vcpu, gfn, gva, level, direct, ACC_ALL);
+       ++sp->root_count;
+
+       spin_unlock(&vcpu->kvm->mmu_lock);
+       return __pa(sp->spt);
+}
+
+static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
+{
+       u8 shadow_root_level = vcpu->arch.mmu->shadow_root_level;
+       hpa_t root;
        unsigned i;
 
-       if (vcpu->arch.mmu->shadow_root_level >= PT64_ROOT_4LEVEL) {
-               spin_lock(&vcpu->kvm->mmu_lock);
-               if(make_mmu_pages_available(vcpu) < 0) {
-                       spin_unlock(&vcpu->kvm->mmu_lock);
+       if (shadow_root_level >= PT64_ROOT_4LEVEL) {
+               root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level, true);
+               if (!VALID_PAGE(root))
                        return -ENOSPC;
-               }
-               sp = kvm_mmu_get_page(vcpu, 0, 0,
-                               vcpu->arch.mmu->shadow_root_level, 1, ACC_ALL);
-               ++sp->root_count;
-               spin_unlock(&vcpu->kvm->mmu_lock);
-               vcpu->arch.mmu->root_hpa = __pa(sp->spt);
-       } else if (vcpu->arch.mmu->shadow_root_level == PT32E_ROOT_LEVEL) {
+               vcpu->arch.mmu->root_hpa = root;
+       } else if (shadow_root_level == PT32E_ROOT_LEVEL) {
                for (i = 0; i < 4; ++i) {
-                       hpa_t root = vcpu->arch.mmu->pae_root[i];
+                       MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i]));
 
-                       MMU_WARN_ON(VALID_PAGE(root));
-                       spin_lock(&vcpu->kvm->mmu_lock);
-                       if (make_mmu_pages_available(vcpu) < 0) {
-                               spin_unlock(&vcpu->kvm->mmu_lock);
+                       root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT),
+                                             i << 30, PT32_ROOT_LEVEL, true);
+                       if (!VALID_PAGE(root))
                                return -ENOSPC;
-                       }
-                       sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
-                                       i << 30, PT32_ROOT_LEVEL, 1, ACC_ALL);
-                       root = __pa(sp->spt);
-                       ++sp->root_count;
-                       spin_unlock(&vcpu->kvm->mmu_lock);
                        vcpu->arch.mmu->pae_root[i] = root | PT_PRESENT_MASK;
                }
                vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root);
@@ -3723,9 +3729,9 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
 
 static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 {
-       struct kvm_mmu_page *sp;
        u64 pdptr, pm_mask;
        gfn_t root_gfn, root_pgd;
+       hpa_t root;
        int i;
 
        root_pgd = vcpu->arch.mmu->get_guest_pgd(vcpu);
@@ -3739,20 +3745,12 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
         * write-protect the guests page table root.
         */
        if (vcpu->arch.mmu->root_level >= PT64_ROOT_4LEVEL) {
-               hpa_t root = vcpu->arch.mmu->root_hpa;
+               MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->root_hpa));
 
-               MMU_WARN_ON(VALID_PAGE(root));
-
-               spin_lock(&vcpu->kvm->mmu_lock);
-               if (make_mmu_pages_available(vcpu) < 0) {
-                       spin_unlock(&vcpu->kvm->mmu_lock);
+               root = mmu_alloc_root(vcpu, root_gfn, 0,
+                                     vcpu->arch.mmu->shadow_root_level, false);
+               if (!VALID_PAGE(root))
                        return -ENOSPC;
-               }
-               sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
-                               vcpu->arch.mmu->shadow_root_level, 0, ACC_ALL);
-               root = __pa(sp->spt);
-               ++sp->root_count;
-               spin_unlock(&vcpu->kvm->mmu_lock);
                vcpu->arch.mmu->root_hpa = root;
                goto set_root_pgd;
        }
@@ -3767,9 +3765,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
                pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
 
        for (i = 0; i < 4; ++i) {
-               hpa_t root = vcpu->arch.mmu->pae_root[i];
-
-               MMU_WARN_ON(VALID_PAGE(root));
+               MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i]));
                if (vcpu->arch.mmu->root_level == PT32E_ROOT_LEVEL) {
                        pdptr = vcpu->arch.mmu->get_pdptr(vcpu, i);
                        if (!(pdptr & PT_PRESENT_MASK)) {
@@ -3780,17 +3776,11 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
                        if (mmu_check_root(vcpu, root_gfn))
                                return 1;
                }
-               spin_lock(&vcpu->kvm->mmu_lock);
-               if (make_mmu_pages_available(vcpu) < 0) {
-                       spin_unlock(&vcpu->kvm->mmu_lock);
-                       return -ENOSPC;
-               }
-               sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30, PT32_ROOT_LEVEL,
-                                     0, ACC_ALL);
-               root = __pa(sp->spt);
-               ++sp->root_count;
-               spin_unlock(&vcpu->kvm->mmu_lock);
 
+               root = mmu_alloc_root(vcpu, root_gfn, i << 30,
+                                     PT32_ROOT_LEVEL, false);
+               if (!VALID_PAGE(root))
+                       return -ENOSPC;
                vcpu->arch.mmu->pae_root[i] = root | pm_mask;
        }
        vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root);