Messages in this thread Patch in this message | | | Date | Fri, 24 Sep 2010 09:24:47 -0700 | From | Greg KH <> | Subject | [59/80] KVM: VMX: Fix host GDT.LIMIT corruption |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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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: Greg Kroah-Hartman <gregkh@suse.de> --- arch/x86/kvm/vmx.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -177,6 +177,7 @@ static u64 construct_eptp(unsigned long 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; @@ -812,6 +813,7 @@ static void __vmx_load_host_state(struct 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) @@ -1314,6 +1316,8 @@ static int hardware_enable(void *garbage ept_sync_global(); + store_gdt(&__get_cpu_var(host_gdt)); + return 0; }
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