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authorSean Christopherson <sean.j.christopherson@intel.com>2018-07-23 21:32:48 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2018-08-06 17:59:16 +0200
commitf3bbc0dcedf50d29d2d6fdfb16c5ec3e2368837f (patch)
tree2d2d58a649b9db40b605e2c1a72015611f21127e /arch/x86/kvm
parentKVM: vmx: move struct host_state usage to struct loaded_vmcs (diff)
downloadlinux-f3bbc0dcedf50d29d2d6fdfb16c5ec3e2368837f.tar.xz
linux-f3bbc0dcedf50d29d2d6fdfb16c5ec3e2368837f.zip
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 <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/vmx.c10
1 files changed, 0 insertions, 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);