[PATCH 18/24] KVM: x86/mmu: propagate access mask from root pages down

[Paolo Bonzini]

Until now, all SPTEs have had all kinds of access allowed; however,
for GMET to be enabled all the pages have to have ACC_USER_MASK
disabled.  By marking them as supervisor pages, the processor
allows execution from either user or supervisor mode (unlike
for normal paging, NPT ignores the U bit for reads and writes).
That will mean that the root page's role has ACC_USER_MASK
cleared and that has to be propagated down through the kvm_mmu_page
tree.

Do that, and pass the required access to the
kvm_mmu_spte_requested tracepoint since it's not ACC_ALL
anymore.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu.c         |  9 +++++----
 arch/x86/kvm/mmu/mmutrace.h    | 10 ++++++----
 arch/x86/kvm/mmu/paging_tmpl.h |  2 +-
 arch/x86/kvm/mmu/tdp_mmu.c     |  6 +++---
 4 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 442cbaeaf547..834ba9c0c809 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3434,12 +3434,13 @@ static int direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 {
 	struct kvm_shadow_walk_iterator it;
 	struct kvm_mmu_page *sp;
-	int ret;
+	int ret, access;
 	gfn_t base_gfn = fault->gfn;
 
 	kvm_mmu_hugepage_adjust(vcpu, fault);
 
-	trace_kvm_mmu_spte_requested(fault);
+	access = vcpu->arch.mmu->root_role.access;
+	trace_kvm_mmu_spte_requested(fault, access);
 	for_each_shadow_entry(vcpu, fault->addr, it) {
 		/*
 		 * We cannot overwrite existing page tables with an NX
@@ -3452,7 +3453,7 @@ static int direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 		if (it.level == fault->goal_level)
 			break;
 
-		sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, true, ACC_ALL);
+		sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, true, access);
 		if (sp == ERR_PTR(-EEXIST))
 			continue;
 
@@ -3465,7 +3466,7 @@ static int direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	if (WARN_ON_ONCE(it.level != fault->goal_level))
 		return -EFAULT;
 
-	ret = mmu_set_spte(vcpu, fault->slot, it.sptep, ACC_ALL,
+	ret = mmu_set_spte(vcpu, fault->slot, it.sptep, access,
 			   base_gfn, fault->pfn, fault);
 	if (ret == RET_PF_SPURIOUS)
 		return ret;
diff --git a/arch/x86/kvm/mmu/mmutrace.h b/arch/x86/kvm/mmu/mmutrace.h
index 3429c1413f42..fa01719baf8d 100644
--- a/arch/x86/kvm/mmu/mmutrace.h
+++ b/arch/x86/kvm/mmu/mmutrace.h
@@ -373,23 +373,25 @@ TRACE_EVENT(
 
 TRACE_EVENT(
 	kvm_mmu_spte_requested,
-	TP_PROTO(struct kvm_page_fault *fault),
-	TP_ARGS(fault),
+	TP_PROTO(struct kvm_page_fault *fault, u8 access),
+	TP_ARGS(fault, access),
 
 	TP_STRUCT__entry(
 		__field(u64, gfn)
 		__field(u64, pfn)
 		__field(u8, level)
+		__field(u8, access)
 	),
 
 	TP_fast_assign(
 		__entry->gfn = fault->gfn;
 		__entry->pfn = fault->pfn | (fault->gfn & (KVM_PAGES_PER_HPAGE(fault->goal_level) - 1));
 		__entry->level = fault->goal_level;
+		__entry->access = access;
 	),
 
-	TP_printk("gfn %llx pfn %llx level %d",
-		  __entry->gfn, __entry->pfn, __entry->level
+	TP_printk("gfn %llx pfn %llx level %d access %x",
+		  __entry->gfn, __entry->pfn, __entry->level, __entry->access
 	)
 );
 
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 95aa1b4fc327..31331fe10723 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -731,7 +731,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
 	 */
 	kvm_mmu_hugepage_adjust(vcpu, fault);
 
-	trace_kvm_mmu_spte_requested(fault);
+	trace_kvm_mmu_spte_requested(fault, gw->pte_access);
 
 	for (; shadow_walk_okay(&it); shadow_walk_next(&it)) {
 		/*
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 9c26038f6b77..25e557de99d6 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1185,9 +1185,9 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
 	}
 
 	if (unlikely(!fault->slot))
-		new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
+		new_spte = make_mmio_spte(vcpu, iter->gfn, sp->role.access);
 	else
-		wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn,
+		wrprot = make_spte(vcpu, sp, fault->slot, sp->role.access, iter->gfn,
 				   fault->pfn, iter->old_spte, fault->prefetch,
 				   false, fault->map_writable, &new_spte);
 
@@ -1272,7 +1272,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 
 	kvm_mmu_hugepage_adjust(vcpu, fault);
 
-	trace_kvm_mmu_spte_requested(fault);
+	trace_kvm_mmu_spte_requested(fault, root->role.access);
 
 	rcu_read_lock();
 
-- 
2.53.0