From 44ea2b1758d88ad822e65b1c4c21ca6164494e27 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 6 Sep 2009 15:55:37 +0300 Subject: [PATCH] KVM: VMX: Move MSR_KERNEL_GS_BASE out of the vmx autoload msr area Currently MSR_KERNEL_GS_BASE is saved and restored as part of the guest/host msr reloading. Since we wish to lazy-restore all the other msrs, save and reload MSR_KERNEL_GS_BASE explicitly instead of using the common code. Signed-off-by: Avi Kivity --- arch/x86/kvm/vmx.c | 39 ++++++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 1773017..3251251 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -99,7 +99,8 @@ struct vcpu_vmx { int save_nmsrs; int msr_offset_efer; #ifdef CONFIG_X86_64 - int msr_offset_kernel_gs_base; + u64 msr_host_kernel_gs_base; + u64 msr_guest_kernel_gs_base; #endif struct vmcs *vmcs; struct { @@ -202,7 +203,7 @@ static void ept_save_pdptrs(struct kvm_vcpu *vcpu); */ static const u32 vmx_msr_index[] = { #ifdef CONFIG_X86_64 - MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR, MSR_KERNEL_GS_BASE, + MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR, #endif MSR_EFER, MSR_K6_STAR, }; @@ -674,10 +675,10 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu) #endif #ifdef CONFIG_X86_64 - if (is_long_mode(&vmx->vcpu)) - save_msrs(vmx->host_msrs + - vmx->msr_offset_kernel_gs_base, 1); - + if (is_long_mode(&vmx->vcpu)) { + rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); + wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base); + } #endif load_msrs(vmx->guest_msrs, vmx->save_nmsrs); load_transition_efer(vmx); @@ -711,6 +712,12 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) save_msrs(vmx->guest_msrs, vmx->save_nmsrs); load_msrs(vmx->host_msrs, vmx->save_nmsrs); reload_host_efer(vmx); +#ifdef CONFIG_X86_64 + if (is_long_mode(&vmx->vcpu)) { + rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base); + wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); + } +#endif } static void vmx_load_host_state(struct vcpu_vmx *vmx) @@ -940,9 +947,6 @@ static void setup_msrs(struct vcpu_vmx *vmx) index = __find_msr_index(vmx, MSR_CSTAR); if (index >= 0) move_msr_up(vmx, index, save_nmsrs++); - index = __find_msr_index(vmx, MSR_KERNEL_GS_BASE); - if (index >= 0) - move_msr_up(vmx, index, save_nmsrs++); /* * MSR_K6_STAR is only needed on long mode guests, and only * if efer.sce is enabled. @@ -954,10 +958,6 @@ static void setup_msrs(struct vcpu_vmx *vmx) #endif vmx->save_nmsrs = save_nmsrs; -#ifdef CONFIG_X86_64 - vmx->msr_offset_kernel_gs_base = - __find_msr_index(vmx, MSR_KERNEL_GS_BASE); -#endif vmx->msr_offset_efer = __find_msr_index(vmx, MSR_EFER); if (cpu_has_vmx_msr_bitmap()) { @@ -1015,6 +1015,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) case MSR_GS_BASE: data = vmcs_readl(GUEST_GS_BASE); break; + case MSR_KERNEL_GS_BASE: + vmx_load_host_state(to_vmx(vcpu)); + data = to_vmx(vcpu)->msr_guest_kernel_gs_base; + break; case MSR_EFER: return kvm_get_msr_common(vcpu, msr_index, pdata); #endif @@ -1068,6 +1072,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) case MSR_GS_BASE: vmcs_writel(GUEST_GS_BASE, data); break; + case MSR_KERNEL_GS_BASE: + vmx_load_host_state(vmx); + vmx->msr_guest_kernel_gs_base = data; + break; #endif case MSR_IA32_SYSENTER_CS: vmcs_write32(GUEST_SYSENTER_CS, data); @@ -1559,6 +1567,11 @@ static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer) struct vcpu_vmx *vmx = to_vmx(vcpu); struct kvm_msr_entry *msr = find_msr_entry(vmx, MSR_EFER); + /* + * Force kernel_gs_base reloading before EFER changes, as control + * of this msr depends on is_long_mode(). + */ + vmx_load_host_state(to_vmx(vcpu)); vcpu->arch.shadow_efer = efer; if (!msr) return; -- 1.8.2.3