From: Avi Kivity <[email protected]> commit 3444d7da1839b851eefedd372978d8a982316c36 upstream.
vmx does not restore GDT.LIMIT to the host value, instead it sets it to 64KB. This means host userspace can learn a few bits of host memory. Fix by reloading GDTR when we load other host state. Signed-off-by: Avi Kivity <[email protected]> Signed-off-by: Marcelo Tosatti <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> --- arch/x86/kvm/vmx.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3c86c42..11db911 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -170,6 +170,7 @@ static u64 construct_eptp(unsigned long root_hpa); static DEFINE_PER_CPU(struct vmcs *, vmxarea); static DEFINE_PER_CPU(struct vmcs *, current_vmcs); static DEFINE_PER_CPU(struct list_head, vcpus_on_cpu); +static DEFINE_PER_CPU(struct desc_ptr, host_gdt); static unsigned long *vmx_io_bitmap_a; static unsigned long *vmx_io_bitmap_b; @@ -717,6 +718,7 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); } #endif + load_gdt(&__get_cpu_var(host_gdt)); } static void vmx_load_host_state(struct vcpu_vmx *vmx) @@ -1218,6 +1220,8 @@ static int hardware_enable(void *garbage) ept_sync_global(); + store_gdt(&__get_cpu_var(host_gdt)); + return 0; } -- 1.7.3.3 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
