linux-kernel - [PATCH 33/54] KVM: x86/mmu: Use MMU's role to compute PKRU bitmask

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Message-Id: <20210622175739.3610207-34-seanjc@google.com>
Date:   Tue, 22 Jun 2021 10:57:18 -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 33/54] KVM: x86/mmu: Use MMU's role to compute PKRU bitmask

Use the MMU's role to calculate the Protection Keys (Restrict Userspace)
bitmask instead of pulling bits from current vCPU state.  For some flows,
the vCPU state may not be correct (or relevant), e.g. EPT doesn't
interact with PKRU.  Case in point, the "ept" param simply disappears.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index bd412e082356..dcde7514358b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4460,24 +4460,17 @@ static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
 * away both AD and WD.  For all reads or if the last condition holds, WD
 * only will be masked away.
 */
-static void update_pkru_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
-				bool ept)
+static void update_pkru_bitmask(struct kvm_mmu *mmu)
 {
 	unsigned bit;
 	bool wp;
 
-	if (ept) {
+	if (!is_cr4_pke(mmu)) {
 		mmu->pkru_mask = 0;
 		return;
 	}
 
-	/* PKEY is enabled only if CR4.PKE and EFER.LMA are both set. */
-	if (!kvm_read_cr4_bits(vcpu, X86_CR4_PKE) || !is_long_mode(vcpu)) {
-		mmu->pkru_mask = 0;
-		return;
-	}
-
-	wp = is_write_protection(vcpu);
+	wp = is_cr0_wp(mmu);
 
 	for (bit = 0; bit < ARRAY_SIZE(mmu->permissions); ++bit) {
 		unsigned pfec, pkey_bits;
@@ -4672,7 +4665,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 	}
 
 	update_permission_bitmask(context, false);
-	update_pkru_bitmask(vcpu, context, false);
+	update_pkru_bitmask(context);
 	update_last_nonleaf_level(vcpu, context);
 	reset_tdp_shadow_zero_bits_mask(vcpu, context);
 }
@@ -4730,7 +4723,7 @@ static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *conte
 	if (____is_cr0_pg(regs)) {
 		reset_rsvds_bits_mask(vcpu, context);
 		update_permission_bitmask(context, false);
-		update_pkru_bitmask(vcpu, context, false);
+		update_pkru_bitmask(context);
 		update_last_nonleaf_level(vcpu, context);
 	}
 	context->shadow_root_level = new_role.base.level;
@@ -4838,8 +4831,8 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 	context->direct_map = false;
 
 	update_permission_bitmask(context, true);
-	update_pkru_bitmask(vcpu, context, true);
 	update_last_nonleaf_level(vcpu, context);
+	update_pkru_bitmask(context);
 	reset_rsvds_bits_mask_ept(vcpu, context, execonly);
 	reset_ept_shadow_zero_bits_mask(vcpu, context, execonly);
 }
@@ -4935,7 +4928,7 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 	}
 
 	update_permission_bitmask(g_context, false);
-	update_pkru_bitmask(vcpu, g_context, false);
+	update_pkru_bitmask(g_context);
 	update_last_nonleaf_level(vcpu, g_context);
 }
 
-- 
2.32.0.288.g62a8d224e6-goog