Commit ffb128c8 authored by Bandan Das's avatar Bandan Das Committed by Paolo Bonzini

kvm: mmu: don't set the present bit unconditionally

To support execute only mappings on behalf of L1
hypervisors, we need to teach set_spte() to honor all three of
L1's XWR bits.  As a start, add a new variable "shadow_present_mask"
that will be set for non-EPT shadow paging and clear for EPT.
Signed-off-by: default avatarBandan Das <bsd@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 812f30b2
...@@ -1031,7 +1031,7 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu); ...@@ -1031,7 +1031,7 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu);
void kvm_mmu_init_vm(struct kvm *kvm); void kvm_mmu_init_vm(struct kvm *kvm);
void kvm_mmu_uninit_vm(struct kvm *kvm); void kvm_mmu_uninit_vm(struct kvm *kvm);
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask, void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
u64 dirty_mask, u64 nx_mask, u64 x_mask); u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask);
void kvm_mmu_reset_context(struct kvm_vcpu *vcpu); void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
......
...@@ -175,6 +175,7 @@ static u64 __read_mostly shadow_user_mask; ...@@ -175,6 +175,7 @@ static u64 __read_mostly shadow_user_mask;
static u64 __read_mostly shadow_accessed_mask; static u64 __read_mostly shadow_accessed_mask;
static u64 __read_mostly shadow_dirty_mask; static u64 __read_mostly shadow_dirty_mask;
static u64 __read_mostly shadow_mmio_mask; static u64 __read_mostly shadow_mmio_mask;
static u64 __read_mostly shadow_present_mask;
static void mmu_spte_set(u64 *sptep, u64 spte); static void mmu_spte_set(u64 *sptep, u64 spte);
static void mmu_free_roots(struct kvm_vcpu *vcpu); static void mmu_free_roots(struct kvm_vcpu *vcpu);
...@@ -282,13 +283,14 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte) ...@@ -282,13 +283,14 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
} }
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask, void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
u64 dirty_mask, u64 nx_mask, u64 x_mask) u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask)
{ {
shadow_user_mask = user_mask; shadow_user_mask = user_mask;
shadow_accessed_mask = accessed_mask; shadow_accessed_mask = accessed_mask;
shadow_dirty_mask = dirty_mask; shadow_dirty_mask = dirty_mask;
shadow_nx_mask = nx_mask; shadow_nx_mask = nx_mask;
shadow_x_mask = x_mask; shadow_x_mask = x_mask;
shadow_present_mask = p_mask;
} }
EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes); EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
...@@ -2245,10 +2247,9 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, ...@@ -2245,10 +2247,9 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep,
{ {
u64 spte; u64 spte;
BUILD_BUG_ON(VMX_EPT_READABLE_MASK != PT_PRESENT_MASK || BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | spte = __pa(sp->spt) | shadow_present_mask | PT_WRITABLE_MASK |
shadow_user_mask | shadow_x_mask | shadow_accessed_mask; shadow_user_mask | shadow_x_mask | shadow_accessed_mask;
mmu_spte_set(sptep, spte); mmu_spte_set(sptep, spte);
...@@ -2515,13 +2516,13 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, ...@@ -2515,13 +2516,13 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
gfn_t gfn, kvm_pfn_t pfn, bool speculative, gfn_t gfn, kvm_pfn_t pfn, bool speculative,
bool can_unsync, bool host_writable) bool can_unsync, bool host_writable)
{ {
u64 spte; u64 spte = 0;
int ret = 0; int ret = 0;
if (set_mmio_spte(vcpu, sptep, gfn, pfn, pte_access)) if (set_mmio_spte(vcpu, sptep, gfn, pfn, pte_access))
return 0; return 0;
spte = PT_PRESENT_MASK; spte |= shadow_present_mask;
if (!speculative) if (!speculative)
spte |= shadow_accessed_mask; spte |= shadow_accessed_mask;
......
...@@ -6473,6 +6473,7 @@ static __init int hardware_setup(void) ...@@ -6473,6 +6473,7 @@ static __init int hardware_setup(void)
(enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull, (enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull, (enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
0ull, VMX_EPT_EXECUTABLE_MASK); 0ull, VMX_EPT_EXECUTABLE_MASK);
0ull, VMX_EPT_EXECUTABLE_MASK, VMX_EPT_READABLE_MASK);
ept_set_mmio_spte_mask(); ept_set_mmio_spte_mask();
kvm_enable_tdp(); kvm_enable_tdp();
} else } else
......
...@@ -5878,8 +5878,8 @@ int kvm_arch_init(void *opaque) ...@@ -5878,8 +5878,8 @@ int kvm_arch_init(void *opaque)
kvm_x86_ops = ops; kvm_x86_ops = ops;
kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK, kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
PT_DIRTY_MASK, PT64_NX_MASK, 0); PT_DIRTY_MASK, PT64_NX_MASK, 0,
PT_PRESENT_MASK);
kvm_timer_init(); kvm_timer_init();
perf_register_guest_info_callbacks(&kvm_guest_cbs); perf_register_guest_info_callbacks(&kvm_guest_cbs);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment