From: Avi Kivity <avi@redhat.com>
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 <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
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
--
