From 3444d7da1839b851eefedd372978d8a982316c36 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Mon, 26 Jul 2010 18:32:38 +0300 Subject: [PATCH] KVM: VMX: Fix host GDT.LIMIT corruption 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 Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/vmx.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 2fdcc9819f3..27a0222c294 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -185,6 +185,7 @@ static void kvm_cpu_vmxoff(void); 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; @@ -871,6 +872,7 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) #endif if (current_thread_info()->status & TS_USEDFPU) clts(); + load_gdt(&__get_cpu_var(host_gdt)); } static void vmx_load_host_state(struct vcpu_vmx *vmx) @@ -1379,6 +1381,8 @@ static int hardware_enable(void *garbage) ept_sync_global(); } + store_gdt(&__get_cpu_var(host_gdt)); + return 0; }