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KVM: VMX: Stuff vcpu->arch.apic_base directly at vCPU RESET

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Write vcpu->arch.apic_base directly instead of bouncing through
kvm_set_apic_base().  This is a glorified nop, and is a step towards
cleaning up the mess that is local APIC creation.

When using an in-kernel APIC, kvm_create_lapic() explicitly sets
vcpu->arch.apic_base to MSR_IA32_APICBASE_ENABLE to avoid its own
kvm_lapic_set_base() call in kvm_lapic_reset() from triggering state
changes.  That call during RESET exists purely to set apic->base_address
to the default base value.  As a result, by the time VMX gets control,
the only missing piece is the BSP bit being set for the reset BSP.

For a userspace APIC, there are no side effects to process (for the APIC).

In both cases, the call to kvm_update_cpuid_runtime() is a nop because
the vCPU hasn't yet been exposed to userspace, i.e. there can't be any
CPUID entries.

No functional change intended.

Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-17-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-07-13 09:32:54 -07:00 committed by Paolo Bonzini
parent 503bc49424
commit f0428b3dcb
1 changed files with 3 additions and 6 deletions

9
arch/x86/kvm/vmx/vmx.c
View File

@ -4391,7 +4391,6 @@ static void init_vmcs(struct vcpu_vmx *vmx)
static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct msr_data apic_base_msr;
u32 eax, dummy;
u64 cr0;
@ -4409,12 +4408,10 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
kvm_set_cr8(vcpu, 0);
if (!init_event) {
apic_base_msr.data = APIC_DEFAULT_PHYS_BASE |
MSR_IA32_APICBASE_ENABLE;
vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE |
MSR_IA32_APICBASE_ENABLE;
if (kvm_vcpu_is_reset_bsp(vcpu))
apic_base_msr.data |= MSR_IA32_APICBASE_BSP;
apic_base_msr.host_initiated = true;
kvm_set_apic_base(vcpu, &apic_base_msr);
vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;
}
vmx_segment_cache_clear(vmx);