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

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Message-Id: <20210622175739.3610207-28-seanjc@google.com>
Date:   Tue, 22 Jun 2021 10:57:12 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Yu Zhang <yu.c.zhang@...ux.intel.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 27/54] KVM: x86/mmu: Set CR4.PKE/LA57 in MMU role iff long
 mode is active

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@...gle.com>
---
 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