KVM: MMU: shadow nested paging does not have PKU

BugLink: https://bugs.launchpad.net/bugs/1953731
commit 28f091bc2f8c23b7eac2402956b692621be7f9f4 upstream.

Initialize the mask for PKU permissions as if CR4.PKE=0, avoiding
incorrect interpretations of the nested hypervisor's page tables.

Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0e0f960a0bf8ef4d487b2b409363abcfbfb197de..b313fd3d3c383be7a821d6fbb844c8b0e9e64bf8 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4852,7 +4852,7 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
        struct kvm_mmu *context = &vcpu->arch.guest_mmu;
        struct kvm_mmu_role_regs regs = {
                .cr0 = cr0,
-               .cr4 = cr4,
+               .cr4 = cr4 & ~X86_CR4_PKE,
                .efer = efer,
        };
        union kvm_mmu_role new_role;
@@ -4916,7 +4916,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
        context->direct_map = false;
 
        update_permission_bitmask(context, true);
-       update_pkru_bitmask(context);
+       context->pkru_mask = 0;
        reset_rsvds_bits_mask_ept(vcpu, context, execonly);
        reset_ept_shadow_zero_bits_mask(vcpu, context, execonly);
 }