From f3bbc0dcedf50d29d2d6fdfb16c5ec3e2368837f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 23 Jul 2018 12:32:48 -0700 Subject: [PATCH] KVM: vmx: always initialize HOST_{FS,GS}_BASE to zero during setup The HOST_{FS,GS}_BASE fields are guaranteed to be written prior to VMENTER, by way of vmx_prepare_switch_to_guest(). Initialize the fields to zero for 64-bit kernels instead of pulling the base values from their respective MSRs. In addition to eliminating two RDMSRs, vmx_prepare_switch_to_guest() can safely assume the initial value of the fields is zero in all cases. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d0d2374a3170..60bf9a95219f 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6361,9 +6361,6 @@ static void ept_set_mmio_spte_mask(void) */ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) { -#ifdef CONFIG_X86_64 - unsigned long a; -#endif int i; if (enable_shadow_vmcs) { @@ -6418,15 +6415,8 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) vmcs_write16(HOST_FS_SELECTOR, 0); /* 22.2.4 */ vmcs_write16(HOST_GS_SELECTOR, 0); /* 22.2.4 */ vmx_set_constant_host_state(vmx); -#ifdef CONFIG_X86_64 - rdmsrl(MSR_FS_BASE, a); - vmcs_writel(HOST_FS_BASE, a); /* 22.2.4 */ - rdmsrl(MSR_GS_BASE, a); - vmcs_writel(HOST_GS_BASE, a); /* 22.2.4 */ -#else vmcs_writel(HOST_FS_BASE, 0); /* 22.2.4 */ vmcs_writel(HOST_GS_BASE, 0); /* 22.2.4 */ -#endif if (cpu_has_vmx_vmfunc()) vmcs_write64(VM_FUNCTION_CONTROL, 0); -- 2.11.0