diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2011-03-31 11:58:56 -0700 |
|---|---|---|
| committer | AK <andi@firstfloor.org> | 2011-03-31 11:58:56 -0700 |
| commit | c8149a61de28892d8d28fd2180d1f9bbba2c9551 (patch) | |
| tree | 21936b94612c21c0a2bb62c7842bac2c1e880620 | |
| parent | 8aeabadb7ba1c1310bb968950e5f3f1793a58b19 (diff) | |
KVM: VMX: Fix host userspace gsbase corruption
commit c8770e7ba63bb5dd8fe5f9d251275a8fa717fb78 upstream.
We now use load_gs_index() to load gs safely; unfortunately this also
changes MSR_KERNEL_GS_BASE, which we managed separately. This resulted
in confusion and breakage running 32-bit host userspace on a 64-bit kernel.
Fix by
- saving guest MSR_KERNEL_GS_BASE before we we reload the host's gs
- doing the host save/load unconditionally, instead of only when in guest
long mode
Things can be cleaned up further, but this is the minmal fix for now.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
| -rw-r--r-- | arch/x86/kvm/vmx.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 449060ea1450..f1abe23da5d3 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -771,10 +771,9 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu) #endif #ifdef CONFIG_X86_64 - if (is_long_mode(&vmx->vcpu)) { - rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); + rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); + if (is_long_mode(&vmx->vcpu)) wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base); - } #endif for (i = 0; i < vmx->save_nmsrs; ++i) kvm_set_shared_msr(vmx->guest_msrs[i].index, @@ -789,11 +788,14 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) ++vmx->vcpu.stat.host_state_reload; vmx->host_state.loaded = 0; +#ifdef CONFIG_X86_64 + if (is_long_mode(&vmx->vcpu)) + rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base); +#endif if (vmx->host_state.gs_ldt_reload_needed) { kvm_load_ldt(vmx->host_state.ldt_sel); #ifdef CONFIG_X86_64 load_gs_index(vmx->host_state.gs_sel); - wrmsrl(MSR_KERNEL_GS_BASE, current->thread.gs); #else loadsegment(gs, vmx->host_state.gs_sel); #endif @@ -802,10 +804,7 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) loadsegment(fs, vmx->host_state.fs_sel); reload_tss(); #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); - } + wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); #endif load_gdt(&__get_cpu_var(host_gdt)); } |