From c125c607326928001983f51109c3d0c190f0a8bb Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Mon, 1 Feb 2010 22:11:04 +0900 Subject: KVM: fix load_guest_segment_descriptor() to return X86EMUL_* This patch fixes load_guest_segment_descriptor() to return X86EMUL_PROPAGATE_FAULT when it tries to access the descriptor table beyond the limit of it: suggested by Marcelo. I have checked current callers of this helper function, - kvm_load_segment_descriptor() - kvm_task_switch() and confirmed that this patch will change nothing in the upper layers if we do not change the handling of this return value from load_guest_segment_descriptor(). Next step: Although fixing the kvm_task_switch() to handle the propagated faults properly seems difficult, and maybe not worth it because TSS is not used commonly these days, we can fix kvm_load_segment_descriptor(). By doing so, the injected #GP becomes possible to be handled by the guest. The only problem for this is how to differentiate this fault from the page faults generated by kvm_read_guest_virt(). We may have to split this function to achive this goal. Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0bf3df527af..01f0b037092 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4663,7 +4663,7 @@ static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, if (dtable.limit < index * 8 + 7) { kvm_queue_exception_e(vcpu, GP_VECTOR, selector & 0xfffc); - return 1; + return X86EMUL_PROPAGATE_FAULT; } return kvm_read_guest_virt(dtable.base + index*8, seg_desc, sizeof(*seg_desc), vcpu); } -- cgit v1.2.3