[PATCH 42/54] KVM: x86/mmu: Don't update nested guest's paging bitmasks if CR0.PG=0

From: Sean Christopherson
Date: Tue Jun 22 2021 - 14:03:22 EST


Don't bother updating the bitmasks and last-leaf information if paging is
disabled as the metadata will never be used.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 52311c2efd5d..30eb1364fc20 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4646,12 +4646,12 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
context->gva_to_gpa = paging32_gva_to_gpa;
}

- if (is_cr0_pg(context))
+ if (is_cr0_pg(context)) {
reset_rsvds_bits_mask(vcpu, context);
-
- update_permission_bitmask(context, false);
- update_pkru_bitmask(context);
- update_last_nonleaf_level(context);
+ update_permission_bitmask(context, false);
+ update_pkru_bitmask(context);
+ update_last_nonleaf_level(context);
+ }
reset_tdp_shadow_zero_bits_mask(vcpu, context);
}

@@ -4899,12 +4899,12 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
else
g_context->gva_to_gpa = paging32_gva_to_gpa_nested;

- if (is_cr0_pg(g_context))
+ if (is_cr0_pg(g_context)) {
reset_rsvds_bits_mask(vcpu, g_context);
-
- update_permission_bitmask(g_context, false);
- update_pkru_bitmask(g_context);
- update_last_nonleaf_level(g_context);
+ update_permission_bitmask(g_context, false);
+ update_pkru_bitmask(g_context);
+ update_last_nonleaf_level(g_context);
+ }
}

void kvm_init_mmu(struct kvm_vcpu *vcpu)
--
2.32.0.288.g62a8d224e6-goog