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| author | Ben Hutchings <ben@decadent.org.uk> | 2010-11-29 13:00:15 -0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-12-09 13:26:48 -0800 |
| commit | fda45f0be5c9d1671b6bc5b35b6143360f2b10bd (patch) | |
| tree | 77c18fad57a70651c7ec6e7b43c88e648523107d /arch | |
| parent | 91445a8f6fee2f78680bae847cabe237a6e57eb9 (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>
[bwh: Backport to 2.6.32]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d00c64344ee6..d9c4fb6f0ff3 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -654,10 +654,7 @@ 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); - + save_msrs(vmx->host_msrs + vmx->msr_offset_kernel_gs_base, 1); #endif load_msrs(vmx->guest_msrs, vmx->save_nmsrs); load_transition_efer(vmx); @@ -672,17 +669,26 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) vmx->host_state.loaded = 0; if (vmx->host_state.fs_reload_needed) loadsegment(fs, vmx->host_state.fs_sel); +#ifdef CONFIG_X86_64 + if (is_long_mode(&vmx->vcpu)) + save_msrs(vmx->guest_msrs + vmx->msr_offset_kernel_gs_base, 1); +#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 } reload_tss(); +#ifdef CONFIG_X86_64 + save_msrs(vmx->guest_msrs, vmx->msr_offset_kernel_gs_base); + save_msrs(vmx->guest_msrs + vmx->msr_offset_kernel_gs_base + 1, + vmx->save_nmsrs - vmx->msr_offset_kernel_gs_base - 1); +#else save_msrs(vmx->guest_msrs, vmx->save_nmsrs); +#endif load_msrs(vmx->host_msrs, vmx->save_nmsrs); reload_host_efer(vmx); load_gdt(&__get_cpu_var(host_gdt)); |