[lkml]   [2021]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH v2 16/46] KVM: VMX: Stuff vcpu->arch.apic_base directly at vCPU RESET
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 <>
Signed-off-by: Sean Christopherson <>
arch/x86/kvm/vmx/vmx.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 26c0e776827c..e6cc389ec697 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4387,7 +4387,6 @@ 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;

@@ -4408,12 +4407,10 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
kvm_set_cr8(vcpu, 0);

if (!init_event) {
+ vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE |
if (kvm_vcpu_is_reset_bsp(vcpu))
- apic_base_msr.host_initiated = true;
- kvm_set_apic_base(vcpu, &apic_base_msr);
+ vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;

 \ /
  Last update: 2021-07-13 18:35    [W:0.285 / U:1.632 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site