KVM: Fix load_guest_segment_descriptor() to inject page fault
This patch injects page fault when reading descriptor in
load_guest_segment_descriptor() fails with FAULT.
Effects of this injection: This function is used by
kvm_load_segment_descriptor() which is necessary for the
following instructions:
- mov seg,r/m16
- jmp far
- pop ?s
This patch makes it possible to emulate the page faults
generated by these instructions. But be sure that unless
we change the kvm_load_segment_descriptor()'s ret value
propagation this patch has no effect.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f6ae487..203ee7d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4713,6 +4713,9 @@
{
struct descriptor_table dtable;
u16 index = selector >> 3;
+ int ret;
+ u32 err;
+ gva_t addr;
get_segment_descriptor_dtable(vcpu, selector, &dtable);
@@ -4720,9 +4723,13 @@
kvm_queue_exception_e(vcpu, GP_VECTOR, selector & 0xfffc);
return X86EMUL_PROPAGATE_FAULT;
}
- return kvm_read_guest_virt_system(dtable.base + index*8,
- seg_desc, sizeof(*seg_desc),
- vcpu, NULL);
+ addr = dtable.base + index * 8;
+ ret = kvm_read_guest_virt_system(addr, seg_desc, sizeof(*seg_desc),
+ vcpu, &err);
+ if (ret == X86EMUL_PROPAGATE_FAULT)
+ kvm_inject_page_fault(vcpu, addr, err);
+
+ return ret;
}
/* allowed just for 8 bytes segments */