linux-kernel - [PATCH v2 10/49] KVM: x86: Drop now-redundant MAXPHYADDR and GPA rsvd bits from vCPU creation

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Date: Fri, 17 May 2024 10:38:47 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Hou Wenlong <houwenlong.hwl@...group.com>, Kechen Lu <kechenl@...dia.com>, 
	Oliver Upton <oliver.upton@...ux.dev>, Maxim Levitsky <mlevitsk@...hat.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Yang Weijiang <weijiang.yang@...el.com>, 
	Robert Hoo <robert.hoo.linux@...il.com>
Subject: [PATCH v2 10/49] KVM: x86: Drop now-redundant MAXPHYADDR and GPA rsvd
 bits from vCPU creation

Drop the manual initialization of maxphyaddr and reserved_gpa_bits during
vCPU creation now that kvm_arch_vcpu_create() unconditionally invokes
kvm_vcpu_after_set_cpuid(), which handles all such CPUID caching.

None of the helpers between the existing code in kvm_arch_vcpu_create()
and the call to kvm_vcpu_after_set_cpuid() consume maxphyaddr or
reserved_gpa_bits (though auditing vmx_vcpu_create() and svm_vcpu_create()
isn't exactly easy).  And even if that weren't the case, KVM _must_
refresh any affected state during kvm_vcpu_after_set_cpuid(), e.g. to
correctly handle KVM_SET_CPUID2.  In other words, this can't introduce a
new bug, only expose an existing bug (of which there don't appear to be
any).

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/x86.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2f6dda723005..bb34891d2f0a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12190,9 +12190,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 		goto free_emulate_ctxt;
 	}

-	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
-	vcpu->arch.reserved_gpa_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
-
 	vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;

 	kvm_async_pf_hash_reset(vcpu);
-- 
2.45.0.215.g3402c0e53f-goog