KVM: MMU: Replace role.glevels with role.cr4_pae

There is no real distinction between glevels=3 and glevels=4; both have
exactly the same format and the code is treated exactly the same way.  Drop
role.glevels and replace is with role.cr4_pae (which is meaningful).  This
simplifies the code a bit.

As a side effect, it allows sharing shadow page tables between pae and
longmode guest page tables at the same guest page.

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

3 files changed, 10 insertions, 9 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3602728d54de..707d272ae4a1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -171,8 +171,8 @@ struct kvm_pte_chain {
 union kvm_mmu_page_role {
         unsigned word;
         struct {
-                unsigned glevels:4;
                 unsigned level:4;
+                unsigned cr4_pae:1;
                 unsigned quadrant:2;
                 unsigned pad_for_nice_hex_output:6;
                 unsigned direct:1;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ec8900b6692a..51aa580d0aa5 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1206,7 +1206,7 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
 
 static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 {
-        if (sp->role.glevels != vcpu->arch.mmu.root_level) {
+        if (sp->role.cr4_pae != !!is_pae(vcpu)) {
                 kvm_mmu_zap_page(vcpu->kvm, sp);
                 return 1;
         }
@@ -1329,7 +1329,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
         role.level = level;
         role.direct = direct;
         if (role.direct)
-                role.glevels = 0;
+                role.cr4_pae = 0;
         role.access = access;
         if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
@@ -2443,7 +2443,7 @@ static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
         else
                 r = paging32_init_context(vcpu);
 
-        vcpu->arch.mmu.base_role.glevels = vcpu->arch.mmu.root_level;
+        vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
 
         return r;
 }
@@ -2532,7 +2532,7 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
         }
 
         ++vcpu->kvm->stat.mmu_pte_updated;
-        if (sp->role.glevels == PT32_ROOT_LEVEL)
+        if (!sp->role.cr4_pae)
                 paging32_update_pte(vcpu, sp, spte, new);
         else
                 paging64_update_pte(vcpu, sp, spte, new);
@@ -2681,7 +2681,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
                 if (sp->gfn != gfn || sp->role.direct || sp->role.invalid)
                         continue;
-                pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
+                pte_size = sp->role.cr4_pae ? 8 : 4;
                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
                 misaligned |= bytes < 4;
                 if (misaligned || flooded) {
@@ -2705,7 +2705,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                 page_offset = offset;
                 level = sp->role.level;
                 npte = 1;
-                if (sp->role.glevels == PT32_ROOT_LEVEL) {
+                if (!sp->role.cr4_pae) {
                         page_offset <<= 1;      /* 32->64 */
                         /*
                          * A 32-bit pde maps 4MB while the shadow pdes map
diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index 1fe956ab7617..3851f1f3030c 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -28,9 +28,10 @@
                                                                         \
         role.word = __entry->role;                                      \
                                                                         \
-        trace_seq_printf(p, "sp gfn %llx %u/%u q%u%s %s%s %spge"        \
+        trace_seq_printf(p, "sp gfn %llx %u%s q%u%s %s%s %spge"         \
                          " %snxe root %u %s%c",                         \
-                         __entry->gfn, role.level, role.glevels,        \
+                         __entry->gfn, role.level,                      \
+                         role.cr4_pae ? " pae" : "",                    \
                          role.quadrant,                                 \
                          role.direct ? " direct" : "",                  \
                          access_str[role.access],                       \