[PATCH 27/54] KVM: x86/mmu: Set CR4.PKE/LA57 in MMU role iff long mode is active

From: Sean Christopherson
Date: Tue Jun 22 2021 - 14:01:00 EST


Don't set cr4_pke or cr4_la57 in the MMU role if long mode isn't active,
which is required for protection keys and 5-level paging to be fully
enabled. Ignoring the bit avoids unnecessary reconfiguration on reuse,
and also means consumers of mmu_role don't need to manually check for
long mode.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0eb77a45f1ff..31662283dac7 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4574,8 +4574,10 @@ static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu,
ext.cr4_smep = ____is_cr4_smep(regs);
ext.cr4_smap = ____is_cr4_smap(regs);
ext.cr4_pse = ____is_cr4_pse(regs);
- ext.cr4_pke = ____is_cr4_pke(regs);
- ext.cr4_la57 = ____is_cr4_la57(regs);
+
+ /* PKEY and LA57 are active iff long mode is active. */
+ ext.cr4_pke = ____is_efer_lma(regs) && ____is_cr4_pke(regs);
+ ext.cr4_la57 = ____is_efer_lma(regs) && ____is_cr4_la57(regs);
}

ext.valid = 1;
--
2.32.0.288.g62a8d224e6-goog