linux-kernel - [PATCH 17/22] KVM: x86/mmu: remove valid from extended role

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Message-Id: <20220414074000.31438-18-pbonzini@redhat.com>
Date:   Thu, 14 Apr 2022 03:39:55 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH 17/22] KVM: x86/mmu: remove valid from extended role

The level and direct field of the CPU role can act as a marker for validity
instead: exactly one of them is guaranteed to be nonzero, so a zero value
for both means that the role is invalid and the MMU properties will be
computed again.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/include/asm/kvm_host.h | 4 +---
 arch/x86/kvm/mmu/mmu.c          | 8 +++-----
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 52ceeadbed28..1356959a2fe1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -347,8 +347,7 @@ union kvm_mmu_page_role {
  * kvm_mmu_extended_role complements kvm_mmu_page_role, tracking properties
  * relevant to the current MMU configuration.   When loading CR0, CR4, or EFER,
  * including on nested transitions, if nothing in the full role changes then
- * MMU re-configuration can be skipped. @valid bit is set on first usage so we
- * don't treat all-zero structure as valid data.
+ * MMU re-configuration can be skipped.
  *
  * The properties that are tracked in the extended role but not the page role
  * are for things that either (a) do not affect the validity of the shadow page
@@ -365,7 +364,6 @@ union kvm_mmu_page_role {
 union kvm_mmu_extended_role {
 	u32 word;
 	struct {
-		unsigned int valid:1;
 		unsigned int execonly:1;
 		unsigned int cr4_pse:1;
 		unsigned int cr4_pke:1;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index cf8a41675a79..33827d1e3d5a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4699,7 +4699,6 @@ kvm_calc_cpu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
 	role.base.access = ACC_ALL;
 	role.base.smm = is_smm(vcpu);
 	role.base.guest_mode = is_guest_mode(vcpu);
-	role.ext.valid = 1;
 
 	if (!____is_cr0_pg(regs)) {
 		role.base.direct = 1;
@@ -4909,7 +4908,6 @@ kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,
 
 	role.ext.word = 0;
 	role.ext.execonly = execonly;
-	role.ext.valid = 1;
 
 	return role;
 }
@@ -5030,9 +5028,9 @@ void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	vcpu->arch.root_mmu.root_role.word = 0;
 	vcpu->arch.guest_mmu.root_role.word = 0;
 	vcpu->arch.nested_mmu.root_role.word = 0;
-	vcpu->arch.root_mmu.cpu_role.ext.valid = 0;
-	vcpu->arch.guest_mmu.cpu_role.ext.valid = 0;
-	vcpu->arch.nested_mmu.cpu_role.ext.valid = 0;
+	vcpu->arch.root_mmu.cpu_role.as_u64 = 0;
+	vcpu->arch.guest_mmu.cpu_role.as_u64 = 0;
+	vcpu->arch.nested_mmu.cpu_role.as_u64 = 0;
 	kvm_mmu_reset_context(vcpu);
 
 	/*
-- 
2.31.1