[PATCH 5.15 080/207] KVM: MMU: shadow nested paging does not have PKU

Greg Kroah-Hartman
2021-12-06T15:49:38Z

From: Paolo Bonzini <pbonzini@redhat.com>

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>
---
arch/x86/kvm/mmu/mmu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- 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_
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_
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);
}