KVM: x86/mmu: propagate access mask from root pages down

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.

Tested-by: David Riley <d.riley@proxmox.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 935c5f9..f2b162a 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3446,12 +3446,13 @@ 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
@@ -3464,7 +3465,7 @@ 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;
 
@@ -3477,7 +3478,7 @@ 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 3429c14..fa01719 100644 (file)
--- 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 f741f7d..047400a 100644 (file)
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -734,7 +734,7 @@ 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 7b1102d..5a2f8ce 100644 (file)
--- 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();